@article{routh_abdelhamid_colter_el-masry_bedair_2021, title={P-type InxGa1-xN semibulk templates (0.02 < x < 0.16) with room temperature hole concentration of mid-10(19) cm(-3) and device quality surface morphology}, volume={119}, ISSN={["1077-3118"]}, url={https://doi.org/10.1063/5.0065194}, DOI={10.1063/5.0065194}, abstractNote={Using the semibulk approach, p-InxGa1−xN semibulk (p-SB) templates were grown with an indium content ranging from 2.4% to 15.2% via metalorganic chemical vapor deposition. When compared to optimized bulk p-GaN, the hole concentration in p-SB with an In content of ∼15.2% increased by two orders of magnitude from 5.22 × 1017 to 5.28 × 1019 cm−3. The resistivity and mobility of the templates decreased gradually from 3.13 Ω · cm and 3.82 cm2/V s for p-GaN to 0.24 Ω · cm and 0.48 cm2/V s for p-SB with an In content of 15.2%. Temperature dependent Hall measurements were conducted to estimate the activation energy of the p-SB template. The p-SB with the In content of ∼15.2% is estimated to have an activation energy of 29 meV. These heavily doped p-SB templates have comparable material qualities to that of GaN. The atomic force microscopy height retraces of p-SB films show device quality surface morphology, with root mean square roughness ranging from 2.53 to 4.84 nm. The current results can impact the performances of several nitride-based devices, such as laser diodes, LEDs, solar cells, and photodetectors.}, number={12}, journal={APPLIED PHYSICS LETTERS}, author={Routh, Evyn L. and Abdelhamid, Mostafa and Colter, Peter and El-Masry, N. A. and Bedair, S. M.}, year={2021}, month={Sep} }
 @article{routh_abdelhamid_el-masry_bedair_2020, title={Device quality templates of InxGa1-xN (x < 0.1) with defect densities comparable to GaN}, volume={117}, ISSN={["1077-3118"]}, url={https://doi.org/10.1063/5.0015419}, DOI={10.1063/5.0015419}, abstractNote={InGaN/GaN multiple quantum well (MQW) structures currently used in optical devices are based on highly strained InGaN films. The presence of strain reduces quantum efficiency and indium incorporation, two critical parameters in addressing the green gap. We report on the growth of InGaN-relaxed templates on GaN as substrates to reduce the strain in the MQW structures. Relaxation in the InGaN templates, due to the lattice mismatch, is accommodated by the generation of V-pits rather than the formation of misfit dislocations. InxGa1−xN templates (x ∼ 0.1) are grown via a modified semibulk (SB) approach, with a gradually increasing GaN interlayer thickness to provide a mechanism for backfilling of V-pits. We used high-resolution x-ray diffraction rocking curves to quantify the edge-type and screw-type dislocation density present in the SB and compared the results with the etch pit density obtained via atomic force microscopy after treating the SB with a silane etch. Device-quality InGaN templates with defect density in the mid 108 cm−2 were investigated using the above two approaches, with a quality comparable to state-of-the-art GaN.}, number={5}, journal={APPLIED PHYSICS LETTERS}, publisher={AIP Publishing}, author={Routh, Evyn L. and Abdelhamid, Mostafa and El-Masry, N. A. and Bedair, S. M.}, year={2020}, month={Aug} }
 @article{eldred_abdelhamid_reynolds_el-masry_lebeau_bedair_2020, title={Observing relaxation in device quality InGaN templates by TEM techniques}, volume={116}, ISSN={["1077-3118"]}, DOI={10.1063/1.5139269}, abstractNote={Device quality InGaN templates are synthesized using the semibulk (SB) approach. The approach maintains the film's 2D growth and avoids the formation of indium-metal inclusions. The strain relaxation processes of the grown InxGa1−xN templates are accompanied by variations in the indium content (x) and lattice parameters (a and c) across the InGaN template's thickness as the residual strain is continuously decreasing. This strain and lattice parameters' variation creates difficulties in applying standard x-ray Diffraction (XRD) and Reciprocal Space mapping (RSM) techniques to estimate the residual strain and the degree of the elastic strain relaxation. We used high-resolution High-angle annular dark-field scanning transmission electron microscopy and Energy-dispersive x-ray spectroscopy (EDS) to monitor the variations of the indium content, lattice parameters, and strain relaxation across the growing InxGa1−xN templates. We show that strain relaxation takes place by V-pit defect formation. Some of these V-pits are refilled by the GaN interlayers in the InxGa1−xN SB templates, while others propagate to the template surface. We present an alternative approach combining photoluminescence (PL) and EDS for estimating the degree of strain relaxation in these InxGa1−xN templates. The values obtained for the degree of relaxation estimated from TEM studies and PL measurements are within reasonable agreement in this study. Device quality InxGa1−xN templates with x ∼ 0.08, with a degree of relaxation higher than 70%, are achieved.}, number={10}, journal={APPLIED PHYSICS LETTERS}, author={Eldred, Tim B. and Abdelhamid, Mostafa and Reynolds, J. G. and El-Masry, N. A. and LeBeau, James M. and Bedair, S. M.}, year={2020}, month={Mar} }
 @article{abdelhamid_reynolds_el-masry_bedair_2019, title={Growth and characterization of InxGa1-xN (0 < x < 0.16) templates for controlled emissions from MQW}, volume={520}, ISSN={["1873-5002"]}, DOI={10.1016/j.jcrysgro.2019.05.019}, abstractNote={InxGa1−xN (0 < x < 0.16) templates were grown by Metal Organic Chemical Vapor Deposition (MOCVD) using the semibulk (SB) growth approach. We have studied the impact of different SB design parameters such as the number of (InGaN/GaN) periods, InGaN layer thickness (T), and the GaN substrate quality on the SB-template properties, and its degree of relaxation. SIMS characterization measured the variation of indium content (x) in the template, while photoluminescence reflected the indium content at the topmost layers of the SB template. X-ray diffraction techniques measured the average lattice parameters and degree of strain relaxation through the entire InxGa1−xN SB-templates. The SB approach results in superior material quality relative to the bulk grown InGaN, mainly due to its ability to avoid the inclusion of indium-rich clusters and V-pits in the SB templates. The SB approach slows down the relaxation processes and templates as thick as 750 nm are not fully relaxed. We are reporting on methods to enhance the relaxation processes in InxGa1−xN SB-templates. Finally, when InxGa1−xN templates with 0 ≤ x ≤ 0.16 are used as substrates for InGaN/GaN multiple quantum wells, the emission wavelength is shifted from blue to green by changing the indium content in the InxGa1−xN SB-templates. To the best of our knowledge, the current results present the highest indium content reported in InxGa1−xN SB-templates.}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Abdelhamid, Mostafa and Reynolds, J. G. and El-Masry, N. A. and Bedair, S. M.}, year={2019}, month={Aug}, pages={18–26} }
 @article{jagannadham_das_reynolds_el-masry_2018, title={Nature of electrical conduction in MoS2 films deposited by laser physical vapor deposition}, volume={29}, ISSN={0957-4522 1573-482X}, url={http://dx.doi.org/10.1007/S10854-018-9551-9}, DOI={10.1007/S10854-018-9551-9}, number={16}, journal={Journal of Materials Science: Materials in Electronics}, publisher={Springer Science and Business Media LLC}, author={Jagannadham, K. and Das, K. and Reynolds, C. L. and El-Masry, N.}, year={2018}, month={Jun}, pages={14180–14191} }
 @article{el-masry_zavada_reynolds_reynolds_liu_bedair_2017, title={Electric field control of ferromagnetism at room temperature in GaCrN (p-i-n) device structures}, volume={111}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.4986431}, DOI={10.1063/1.4986431}, abstractNote={We have demonstrated a room temperature dilute magnetic semiconductor based on GaCrN epitaxial layers grown by metalorganic chemical vapor deposition. Saturation magnetization Ms increased when the GaCrN film is incorporated into a (p-GaN/i-GaCrN/n-GaN) device structure, due to the proximity of mediated holes present in the p-GaN layer. Zero field cooling and field cooling were measured to ascertain the absence of superparamagnetic behavior in the films. A (p-GaN/i-GaCrN/n-GaN) device structure with room temperature ferromagnetic (FM) properties that can be controlled by an external applied voltage has been fabricated. In this work, we show that the applied voltage controls the ferromagnetic properties, by biasing the (p-i-n) structure. With forward bias, ferromagnetism in the GaCrN layer was increased nearly 4 fold of the original value. Such an enhancement is due to carrier injection of holes into the Cr deep level present in the i-GaCrN layer. A “memory effect” for the FM behavior of the (p-i-n) GaCrN device structure persisted for 42 h after the voltage bias was turned off. These measurements also support that the observed ferromagnetism in the GaCrN film is not due to superparamagnetic clusters but instead is a hole-mediated phenomenon.}, number={8}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={El-Masry, N. A. and Zavada, J. M. and Reynolds, J. G. and Reynolds, C. L., Jr. and Liu, Z. and Bedair, S. M.}, year={2017}, month={Aug}, pages={082402} }
 @article{van den broeck_bharrat_liu_el-masry_bedair_2015, title={Growth and Characterization of High-Quality, Relaxed In (y) Ga1-y N Templates for Optoelectronic Applications}, volume={44}, ISSN={["1543-186X"]}, DOI={10.1007/s11664-015-3989-9}, number={11}, journal={JOURNAL OF ELECTRONIC MATERIALS}, author={Van Den Broeck, D. M. and Bharrat, D. and Liu, Z. and El-Masry, N. A. and Bedair, S. M.}, year={2015}, month={Nov}, pages={4161–4166} }
 @article{you_liu_jiang_wang_el-masry_hosalli_bedair_xu_2014, title={Enhanced radiative recombination and suppressed Auger process in semipolar and nonpolar InGaN/GaN quantum wells grown over GaN nanowires}, volume={39}, ISSN={["1539-4794"]}, DOI={10.1364/ol.39.001501}, abstractNote={The mechanism behind the improved light emission properties of semipolar and nonpolar InGaN/GaN multiple quantum wells (MQWs) conformally grown over n-GaN nanowires (NWs) was studied using variable-temperature photoluminescence and time-resolved photoluminescence (TRPL). A reduced internal polarization electric field was found to account for the observed enhancement in the radiative recombination rate and internal quantum efficiency of the MQWs on NWs. Additionally, the excitation-dependent TRPL results indicate a significantly depressed Auger recombination in MQWs grown on NWs that can be attributed to the feature of ultralow dislocation density of the MQWs grown over GaN nanostructures.}, number={6}, journal={OPTICS LETTERS}, author={You, Guanjun and Liu, Jie and Jiang, Zhenyu and Wang, Li and El-Masry, N. A. and Hosalli, A. M. and Bedair, Salah M. and Xu, Jian}, year={2014}, month={Mar}, pages={1501–1504} }
 @article{broeck_bharrat_hosalli_el-masry_bedair_2014, title={Strain-balanced InGaN/GaN multiple quantum wells}, volume={105}, ISSN={["1077-3118"]}, DOI={10.1063/1.4890738}, abstractNote={InGaN/GaN multiple quantum well (MQW) structures suffer from a high amount of compressive strain in the InGaN wells and the accompanied piezoelectric field resulting in both a blue shift in emission and a reduction of emission intensity. We report the growth of InxGa1−xN/GaN “strain-balanced” multiple quantum wells (SBMQWs) grown on thick InyGa1−yN templates for x > y by metal organic chemical vapor deposition. SBMQWs consist of alternating layers of InxGa1−xN wells and GaN barriers under compressive and tensile stress, respectively, which have been lattice matched to a thick InyGa1−yN template. Growth of the InyGa1−yN template is also detailed in order to achieve thick, relaxed InyGa1−yN grown on GaN without the presence of V-grooves. When compared to conventional InxGa1−xN/GaN MQWs grown on GaN, the SBMQW structures exhibit longer wavelength emission and higher emission intensity for the same InN mole fraction due to a reduction in the well strain and piezoelectric field. By matching the average lattice constant of the MQW active region to the lattice constant of the InyGa1−yN template, essentially an infinite number of periods can be grown using the SBMQW growth method without relaxation-related effects. SBMQWs can be utilized to achieve longer wavelength emission in light emitting diodes without the use of excess indium and can be advantageous in addressing the “green gap.”}, number={3}, journal={APPLIED PHYSICS LETTERS}, author={Broeck, D. M. and Bharrat, D. and Hosalli, A. M. and El-Masry, N. A. and Bedair, S. M.}, year={2014}, month={Jul} }
 @article{bradshaw_carlin_samberg_el-masry_colter_bedair_2013, title={Carrier Transport and Improved Collection in Thin-Barrier InGaAs/GaAsP Strained Quantum Well Solar Cells}, volume={3}, ISSN={["2156-3381"]}, DOI={10.1109/jphotov.2012.2216858}, abstractNote={Multiple quantum wells (MQW) lattice matched to GaAs consisting of In0.14Ga0.76As wells balanced with GaAs0.24P0.76 barriers have been used to extend the absorption of GaAs subcells to longer wavelengths for use in an InGaP/GaAs/Ge triple-junction photovoltaic cell. Thin barriers with high-phosphorus composition are capable of balancing the strain from the InGaAs wells; thus, creating conditions to allow for thicker wells and for carrier tunneling to dominate transport across the structure. As a result, a larger percentage of the depletion region is occupied by InGaAs quantum wells that absorb wavelengths beyond 875 nm and the indium composition is not limited by thermionic emission requirements. Measurements at elevated temperatures and reverse bias suggest that a thermally assisted tunneling mechanism is responsible for transport through the barriers.}, number={1}, journal={IEEE JOURNAL OF PHOTOVOLTAICS}, author={Bradshaw, Geoffrey K. and Carlin, C. Zachary and Samberg, Joshua P. and El-Masry, Nadia A. and Colter, Peter C. and Bedair, Salah M.}, year={2013}, month={Jan}, pages={278–283} }
 @article{bharrat_hosalli_van den broeck_samberg_bedair_el-masry_2013, title={Gallium nitride nanowires by maskless hot phosphoric wet etching}, volume={103}, ISSN={["1077-3118"]}, DOI={10.1063/1.4819272}, abstractNote={We demonstrate gallium nitride (GaN) nanowires formation by controlling the selective and anisotropic etching of N-polar GaN in hot phosphoric acid. Nanowires of ∼109/cm,2 total height of ∼400 nm, and diameters of 170–200 nm were obtained. These nanowires have both non-polar {11¯00}/ {112¯0} and semi-polar {1011¯} facets. X–Ray Diffraction characterization shows that screw dislocations are primarily responsible for preferential etching to create nanowires. Indium gallium nitride multi-quantum wells (MQWs) grown on these GaN nanowires showed a blue shift in peak emission wavelength of photoluminescence spectra, and full width at half maximum decreased relative to MQWs grown on planar N-polar GaN, respectively.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Bharrat, D. and Hosalli, A. M. and Van Den Broeck, D. M. and Samberg, J. P. and Bedair, S. M. and El-Masry, N. A.}, year={2013}, month={Aug} }
 @article{samberg_alipour_bradshaw_carlin_colter_lebeau_el-masry_bedair_2013, title={Interface properties of Ga(As,P)/(In,Ga)As strained multiple quantum well structures}, volume={103}, ISSN={["0003-6951"]}, DOI={10.1063/1.4818548}, abstractNote={(In,Ga)As/Ga(As,P) multiple quantum wells (MQWs) with GaAs interface layers have been characterized with photoluminescence (PL) and high resolution scanning transmission electron microscopy (STEM). By growing (In,Ga)As/Ga(As,P) MQWs with asymmetric GaAs interfacial layers, we found that phosphorus carry-over had a profound effect on the absorption edge of the (In,Ga)As wells. Evidence for this phosphorus was initially determined via PL and then definitively proven through STEM and energy dispersive x-ray spectroscopy. We show that the phosphorus carry-over can be prevented with sufficiently thick GaAs transition layers. Preliminary results for GaAs p-i-n solar cells utilizing the improved MQWs are presented.}, number={7}, journal={APPLIED PHYSICS LETTERS}, author={Samberg, Joshua P. and Alipour, Hamideh M. and Bradshaw, Geoffrey K. and Carlin, C. Zachary and Colter, Peter C. and LeBeau, James M. and El-Masry, N. A. and Bedair, Salah M.}, year={2013}, month={Aug} }
 @article{hosalli_van den broeck_bharrat_el-masry_bedair_2013, title={Inversion by metalorganic chemical vapor deposition from N- to Ga-polar gallium nitride and its application to multiple quantum well light-emitting diodes}, volume={103}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.4841755}, DOI={10.1063/1.4841755}, abstractNote={We demonstrate a metalorganic chemical vapor deposition growth approach for inverting N-polar to Ga-polar GaN by using a thin inversion layer grown with high Mg flux. The introduction of this inversion layer allowed us to grow p-GaN films on N-polar GaN thin film. We have studied the dependence of hole concentration, surface morphology, and degree of polarity inversion for the inverted Ga-polar surface on the thickness of the inversion layer. We then use this approach to grow a light emitting diode structure which has the MQW active region grown on the advantageous N-polar surface and the p-layer grown on the inverted Ga-polar surface.}, number={23}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Hosalli, A. M. and Van Den Broeck, D. M. and Bharrat, D. and El-Masry, N. A. and Bedair, S. M.}, year={2013}, month={Dec}, pages={231108} }
 @article{frajtag_nepal_paskova_bedair_el-masry_2013, title={Multifacet semipolar formation by controlling the groove depth via lateral sidewall epitaxy}, volume={367}, ISSN={["1873-5002"]}, DOI={10.1016/j.jcrysgro.2012.12.039}, abstractNote={We demonstrate InxGa1−xN/GaN light emitting diode structures with different sets of multifacet semipolar formation grown laterally on m-plane sidewalls formed by stripe patterning on preliminary grown c-plane GaN template. It was found that regrowth on shallow side walls within the GaN template resulted in a single semipolar (11¯01) facet, while deeper side walls led to multifacet semipolar formation. Very deep etching through the entire GaN template reaching the underlying sapphire substrates resulted in a combination of semipolar (11¯01) and nonpolar (11¯00) facets. The results indicate that the depth of the groove patterning can be used as a tool for controlling the set of semipolar facet formation. In addition, the growth rate in different crystallographic directions was studied and possible factors affecting the growth rates are discussed.}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Frajtag, P. and Nepal, N. and Paskova, T. and Bedair, S. M. and El-Masry, N. A.}, year={2013}, month={Mar}, pages={88–93} }
 @inproceedings{samberg_bradshaw_carlin_colter_edmondson_hong_fetzer_karam_el-masry_bedair_2013, title={Tandem InGaP/GaAs-quantum well solar cells and their potential improvement through phosphorus carry-over management in multiple quantum well structures}, DOI={10.1109/pvsc.2013.6744479}, abstractNote={InGaP/GaAs/Ge multijunction solar cell (MJSC) efficiency can be increased through improved current matching among the subcells with multiple quantum wells (MQWs) being promising for this purpose. In this study we show that InGaAs/GaAsP QWs utilizing high phosphorus composition barriers can be successfully incorporated into the GaAs subcell of an InGaP/GaAs tandem solar cell. This InGaP/GaAs-MQW device has an enhanced short circuit current density when compared to that of a standard InGaP/GaAs tandem device with minimal impact on either GaAs or InGaP subcell open circuit voltage. Additionally, phosphorus carry-over in the MQW structure is investigated through the use of photoluminescence (PL). It is demonstrated that the phosphorus carry-over can be overcome through the utilization of thick GaAs transition layers at the GaAsP→InGaAs interfaces, resulting in a MQW with an extended absorption edge.}, booktitle={2013 ieee 39th photovoltaic specialists conference (pvsc)}, author={Samberg, J. P. and Bradshaw, G. K. and Carlin, C. Z. and Colter, P. C. and Edmondson, K. and Hong, W. and Fetzer, C. and Karam, N. and El-Masry, N. A. and Bedair, S. M.}, year={2013}, pages={1737–1740} }
 @article{frajtag_hosalli_samberg_colter_paskova_el-masry_bedair_2012, title={Overgrowth of GaN on GaN nanowires produced by mask-less etching}, volume={352}, ISSN={["0022-0248"]}, DOI={10.1016/j.jcrysgro.2011.12.055}, abstractNote={We report on the generation of GaN nanowires (NWs) using mask-less reactive ion etching (RIE). The NWs are believed to be the result of a high etching rate in regions where a high dislocation density is present in the GaN films grown on sapphire substrates. We have studied the effect of defect densities in the original GaN films and its relation to the generation of these NWs. We show that defect reduction in the overgrown GaN is related to the presence of a network of embedded voids generated between these nanowires during the regrowth on the etched nanowires. We show that further reduction in dislocation density can be achieved by repeating the process of nanowire generation and overgrowth. Also we report on the residual strain and curvature in GaN after the first and second embedded voids approach (EVA).}, number={1}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Frajtag, P. and Hosalli, A. M. and Samberg, J. P. and Colter, P. C. and Paskova, T. and El-Masry, N. A. and Bedair, S. M.}, year={2012}, month={Aug}, pages={203–208} }
 @article{frajtag_el-masry_nepal_bedair_2011, title={Embedded voids approach for low defect density in epitaxial GaN films}, volume={98}, ISSN={["1077-3118"]}, DOI={10.1063/1.3540680}, abstractNote={We have developed a technique for defect reduction in GaN epitaxial films grown on sapphire substrates. This technique relies on the generation of high densities of embedded microvoids (∼108/cm2), a few microns long and less than a micron in diameter. These voids are located near the sapphire substrate, where high densities of dislocations are present. Network of embedded voids offer free surfaces that act as dislocation sinks or termination sites for the dislocations generated at the GaN/sapphire interface. Both transmission electron and atomic force microscopy results confirm the uniform reduction of the dislocation density by two orders of magnitude.}, number={2}, journal={APPLIED PHYSICS LETTERS}, author={Frajtag, P. and El-Masry, N. A. and Nepal, N. and Bedair, S. M.}, year={2011}, month={Jan} }
 @article{frajtag_samberg_el-masry_nepal_bedair_2011, title={Embedded voids formation by overgrowth on GaN nanowires for high-quality GaN films}, volume={322}, ISSN={["0022-0248"]}, DOI={10.1016/j.jcrysgro.2011.02.032}, abstractNote={We report on the epitaxial growth of GaN films on GaN nanowires. GaN nanowires were prepared by the mask-less dry etching technique. The etched, then annealed nanowires form semi-polar and non-polar plane facets with hexagonal symmetry. The different growth rates on the different plane facets result in the formation of void networks. These networks of embedded voids are located near the sapphire substrate, where a high density of dislocations is present. The voids, a few microns in length and a fraction of a micron in diameter, offer free surfaces for dislocation termination, enabling the embedded void approach (EVA) to reduce dislocations. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) studies show uniform reduction of the dislocation density over large area substrates by about three orders of magnitude and lower surface roughness than the GaN starting material.}, number={1}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Frajtag, P. and Samberg, J. P. and El-Masry, N. A. and Nepal, N. and Bedair, S. M.}, year={2011}, month={May}, pages={27–32} }
 @article{frajtag_hosalli_bradshaw_nepal_el-masry_bedair_2011, title={Improved light-emitting diode performance by conformal overgrowth of multiple quantum wells and fully coalesced p-type GaN on GaN nanowires}, volume={98}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.3572032}, DOI={10.1063/1.3572032}, abstractNote={We demonstrate a light-emitting diode (LED) structure with multiple quantum wells (MQWs) conformally grown on semipolar and nonpolar plane facets of n-GaN nanowires (NWs), followed by deposition of fully coalesced p-GaN on these nanowires. Overgrowth on the nanowires’ tips results in inclusion of high density voids, about one micron in height, in the GaN film. The light output intensity of NWs LEDs is more than three times higher than corresponding c-plane LEDs grown simultaneously. We believe this results from a reduced defect density, increased effective area of conformally grown MQWs, absence of polar plane orientation, and improved light extraction.}, number={14}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Frajtag, P. and Hosalli, A. M. and Bradshaw, G. K. and Nepal, N. and El-Masry, N. A. and Bedair, S. M.}, year={2011}, month={Apr}, pages={143104} }
 @article{nepal_frajtag_zavada_el-masry_bedair_wetzel_khan_2011, title={Light emitting diodes based on sidewall m-plane epitaxy of etched GaN/sapphire templates}, volume={8}, ISSN={["1862-6351"]}, DOI={10.1002/pssc.201000983}, abstractNote={Abstract}, number={7-8}, journal={PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 7-8}, author={Nepal, N. and Frajtag, P. and Zavada, J. M. and El-Masry, N. A. and Bedair, S. M. and Wetzel, C and Khan, A}, year={2011} }
 @article{emar_berkman_zavada_el-masry_bedair_2011, title={Strain relaxation in InxGa1-xN/GaN quantum well structures}, volume={8}, ISSN={1862-6351}, url={http://dx.doi.org/10.1002/pssc.201000984}, DOI={10.1002/pssc.201000984}, abstractNote={Abstract}, number={7-8}, journal={physica status solidi (c)}, publisher={Wiley}, author={Emar, Ahmed M. and Berkman, E. Acar and Zavada, J. and El-Masry, Nadia A. and Bedair, S. M.}, year={2011}, month={May}, pages={2034–2037} }
 @inproceedings{luen_nepal_frajtag_zavada_brown_hommerich_bedair_el masry_2010, title={Ferromagnetism and near infrared luminescence in neodymium and erbium doped gallium nitride via diffusion}, volume={1183}, DOI={10.1557/proc-1183-ff06-01}, abstractNote={Abstract}, booktitle={Novel materials and devices for spintronics}, author={Luen, M. O. and Nepal, N. and Frajtag, P. and Zavada, J. M. and Brown, E. and Hommerich, U. and Bedair, S. M. and El Masry, N. A.}, year={2010}, pages={45–50} }
 @article{nepal_luen_zavada_bedair_frajtag_el-masry_2009, title={Electric field control of room temperature ferromagnetism in III-N dilute magnetic semiconductor films}, volume={94}, ISSN={["1077-3118"]}, DOI={10.1063/1.3110963}, abstractNote={We report on the electrical field control of ferromagnetism (FM) at room temperature in III-N dilute magnetic semiconductor (DMS) films. A GaMnN layer was grown on top of an n-GaN substrate and found to be almost always paramagnetic. However, when grown on a p-type GaN layer, a strong saturation magnetization (Ms) was observed. This FM in GaMnN can be controlled by depletion of the holes in the GaMnN/p-GaN/n-GaN multilayer structures. We have demonstrated the dependence of the FM on the thickness of the p-GaN in this heterostructure and on the applied bias to the GaN p-n junction. The Ms was measured by an alternating gradient magnetometer (AGM) and a strong correlation between the hole concentration near the GaMnN/p-GaN interface and the magnetic properties of the DMS was observed. At room temperature an anomalous Hall effect was measured for zero bias and an ordinary Hall effect for reverse bias in a fully depleted p-GaN layer. This is in close agreement with the AGM measurement results.}, number={13}, journal={APPLIED PHYSICS LETTERS}, author={Nepal, N. and Luen, M. Oliver and Zavada, J. M. and Bedair, S. M. and Frajtag, P. and El-Masry, N. A.}, year={2009}, month={Mar} }
 @article{berkman_el-masry_emara_bedair_2008, title={Nearly lattice-matched n, i, and p layers for InGaN p-i-n photodiodes in the 365-500 nm spectral range}, volume={92}, ISSN={["0003-6951"]}, DOI={10.1063/1.2896648}, abstractNote={We report on nearly lattice-matched grown InGaN based p-i-n photodiodes detecting in the 365–500nm range with tunable peak responsivity tailored by the i-layer properties. The growth of lattice matched i- and n-InGaN layer leads to improvement in the device performance. This approach produced photodiodes with zero-bias responsivities up to 0.037A∕W at 426nm, corresponding to 15.5% internal quantum efficiency. The peak responsivity wavelength ranged between 416 and 466nm, the longest reported for III-N photodiodes. The effects of InN content and i-layer thickness on photodiode properties and performance are discussed.}, number={10}, journal={APPLIED PHYSICS LETTERS}, author={Berkman, E. A. and El-Masry, N. A. and Emara, A. and Bedair, S. M.}, year={2008}, month={Mar} }
 @article{jagannadham_berkman_elmasry_2008, title={Thermal conductivity of semi-insulating, p-type, and n-type GaN films on sapphire}, volume={26}, ISSN={["1520-8559"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-42949135532&partnerID=MN8TOARS}, DOI={10.1116/1.2899379}, abstractNote={The thermal conductivity of undoped, n-type, and p-type GaN films deposited on (0001) substrates of sapphire was measured by the 3-ω method in the temperature range between 215 and 300K. The thickness, thermal conductivity, and heat capacity of the individual layers were used to simulate the experimental value of the increment in temperature of the heater using a multilayer model. The thermal conductivity of undoped GaN film was found to be much higher than that of p-type film. Also, the thermal conductivity of n-type GaN film was slightly smaller than that of p-type film. Modeling of the temperature dependence of the thermal conductivity in the films showed that phonon-dopant and three-phonon umklapp scattering are important. Smaller thickness and hence smaller volume fraction of the film with lower dislocation density was also found to be responsible for lower thermal conductivity in n- and p-type GaN films.}, number={3}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Jagannadham, K. and Berkman, E. A. and Elmasry, N.}, year={2008}, month={May}, pages={375–379} }
 @article{nepal_bedair_el-masry_lee_steckl_zavada_2007, title={Correlation between compositional fluctuation and magnetic properties of Tm-doped AlGaN alloys}, volume={91}, ISSN={["1077-3118"]}, DOI={10.1063/1.2817741}, abstractNote={The magnetic properties of Tm-doped AlxGa1−xN (0⩽x⩽1) alloys grown by solid-source molecular beam epitaxy were studied by hysteresis measurements and shown to exhibit ferromagnetic behavior at room temperature. The measured magnetization was strongly dependent on the Al content and reached a maximum for x=0.62. Previously reported photoluminescence measurements on these films yielded a blue emission at 465nm with peak intensity at the same Al content. Both magnetic and optical properties are directly correlated with the alloy compositional fluctuation found in undoped AlxGa1−xN alloys.}, number={22}, journal={APPLIED PHYSICS LETTERS}, author={Nepal, N. and Bedair, S. M. and El-Masry, N. A. and Lee, D. S. and Steckl, A. J. and Zavada, J. M.}, year={2007}, month={Nov} }
 @article{nepal_mahros_bedair_el-masry_zavada_2007, title={Correlation between photoluminescence and magnetic properties of GaMnN films}, volume={91}, ISSN={["1077-3118"]}, DOI={10.1063/1.2823602}, abstractNote={GaMnN films grown by metal-organic chemical vapor deposition were studied by photoluminescence (PL) spectroscopy and hysteresis measurements. Depending on the growth conditions of these GaMnN films, hysteresis measurements along the easy axis of magnetization show a transformation from magnetic to nonmagnetic behavior. The PL spectra of both magnetic and nonmagnetic GaMnN films exhibited GaN band edge and deep-level impurity transitions at 3.4 and 1.3eV, respectively. The PL emission intensity of the 1.3eV emission peak is stronger considerably for magnetic GaMnN films and is believed to be due to the Mn3+ intraband transition.}, number={24}, journal={APPLIED PHYSICS LETTERS}, author={Nepal, N. and Mahros, Amr M. and Bedair, S. M. and El-Masry, N. A. and Zavada, J. M.}, year={2007}, month={Dec} }
 @article{barletta_berkman_moody_el-masry_emara_reed_bedair_2007, title={Development of green, yellow, and amber light emitting diodes using InGaN multiple quantum well structures}, volume={90}, ISSN={["0003-6951"]}, DOI={10.1063/1.2721133}, abstractNote={The authors present optical and electrical data for long wavelength (573–601nm) InGaN∕GaN multiple quantum well light emitting diodes (LEDs) grown by metal organic chemical vapor deposition. These results are achieved by optimizing the active layer growth temperature and the quantum well width. Also, the p-GaN is grown at low temperature to avoid the disintegration of the InGaN quantum wells with high InN content. A redshift is observed for both the green and yellow LEDs upon decreasing the injection current at low current regime. In the case of the yellow LED, this shift is enough to push emission into the amber (601nm).}, number={15}, journal={APPLIED PHYSICS LETTERS}, author={Barletta, Philip T. and Berkman, E. Acar and Moody, Baxter F. and El-Masry, Nadia A. and Emara, Ahmed M. and Reed, Mason J. and Bedair, S. M.}, year={2007}, month={Apr} }
 @article{mahros_luen_emara_bedair_berkman_el-masry_zavada_2007, title={Magnetic and magnetotransport properties of (AlGaN/GaN): Mg/(GaMnN) heterostructures at room temperature}, volume={90}, ISSN={["0003-6951"]}, DOI={10.1063/1.2749717}, abstractNote={Dilute magnetic semiconductor films (GaMnN) are highly resistive, making transport measurements difficult to achieve. However, when GaMnN films are sandwiched between p-type doped (AlGaN∕GaN) strained-layer superlattices, holes from the superlattice interact with the Mn3+∕2+ ions and transport measurements were realized. The authors have found also that the ferromagnetic properties of GaMnN critically depend on the level of p-type doping in the superlattice. They report anomalous Hall effect measurements in this (AlGaN∕GaN):Mg∕(GaMnN) multilayered structure. The current results also demonstrate the role of carriers, especially holes, in mediating the ferromagnetic properties of GaMnN dilute magnetic semiconductor films.}, number={25}, journal={APPLIED PHYSICS LETTERS}, author={Mahros, Amr M. and Luen, M. O. and Emara, A. and Bedair, S. M. and Berkman, E. A. and El-Masry, N. A. and Zavada, J. M.}, year={2007}, month={Jun} }
 @article{reed_arkun_berkman_elmasry_zavada_luen_reed_bedair_2005, title={Effect of doping on the magnetic properties of GaMnN: Fermi level engineering}, volume={86}, ISSN={["1077-3118"]}, DOI={10.1063/1.1881786}, abstractNote={GaMnN dilute magnetic semiconductor samples, prepared by metalorganic chemical vapor deposition, are shown to exhibit ferromagnetism or even paramagnetism depending upon the type and concentration of extrinsic impurity present in the film. In addition, GaMnN deposited using growth parameters normally yielding a nonferromagnetic film becomes strongly ferromagnetic with the addition of magnesium, an acceptor dopant. Based upon these observations, it seems that ferromagnetism in this material system depends on the relative position of the Mn energy band and the Fermi level within the GaMnN band gap. Only when the Fermi level closely coincides with the Mn-energy level is ferromagnetism achieved. By actively engineering the Fermi energy to be within or near the Mn energy band, room temperature ferromagnetism is realized.}, number={10}, journal={APPLIED PHYSICS LETTERS}, author={Reed, MJ and Arkun, FE and Berkman, EA and Elmasry, NA and Zavada, J and Luen, MO and Reed, ML and Bedair, SM}, year={2005}, month={Mar} }
 @article{elmasry_hunter_elnaggar_bedair_2005, title={Five-nanometer thick silicon on insulator layer}, volume={98}, ISSN={["0021-8979"]}, DOI={10.1063/1.1803625}, abstractNote={Silicon on insulator (SOI) has been achieved using epitaxially grown Si∕Y2O3∕Si structure. Silicon film as thin as 5nm was achieved. Pulsed laser deposition technique was used for the epitaxial deposition of both the Y2O3 and silicon. The growth conditions were adjusted to achieve two-dimensional growths of single crystal silicon films on Y2O3. No dislocations were observed in these silicon epitaxial films. This approach will allow the independent thickness control of both silicon and the oxide in the nanometer range. Si∕CeO2∕Si SOI structure was not as successful due to the formation of an amorphous oxide film at the interfaces.}, number={10}, journal={JOURNAL OF APPLIED PHYSICS}, author={Elmasry, NA and Hunter, M and ElNaggar, A and Bedair, SM}, year={2005}, month={Nov} }
 @article{reed_reed_luen_berkman_arkun_bedair_zavada_el-masry_2005, title={Magnetic properties of Mn-doped GaN andp-i-n junctions}, volume={2}, ISSN={1610-1634 1610-1642}, url={http://dx.doi.org/10.1002/pssc.200461517}, DOI={10.1002/pssc.200461517}, abstractNote={We report on the growth and magnetic properties of GaMnN films and p-i-n junctions grown by metal-organic chemical vapor deposition. The magnetic properties of MOCVD grown GaMnN were found to depend upon the type and concentration of the co-dopant. Si or Mg co-doping of GaMnN films led to either ferromagnetic or paramagnetic behavior depending on the concentration. The magnetic properties within the GaMnN material system appear to correlate with the position of the Fermi level. Ferromagnetism was observed only when the Fermi energy level was within or very close to the Mn energy band. The presence of the Fermi energy level within the Mn energy band allows the presence of carriers that mediate ferromagnetism. These results further confirm that the ferromagnetic properties result from a solid solution of Mn in the GaN. Mn-doped GaN p-i-n junctions which were grown to study the effect of the magnetic properties on the I/V characteristics. These devices consist of GaN:Si/GaMnN/GaN:Mg layers grown by metal-organic chemical vapor deposition. The carrier concentrations for the n and p-type layers are ∼5 × 1018/cm3 and 1 × 1018/cm3 respectively, where the GaMnN i layer is approximately 0.2–0.45 µm thick with up to 0.5% Mn. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)}, number={7}, journal={physica status solidi (c)}, publisher={Wiley}, author={Reed, M.L. and Reed, M.J. and Luen, M.O. and Berkman, E.A. and Arkun, F.E. and Bedair, S.M. and Zavada, J.M. and El-Masry, N. A.}, year={2005}, month={May}, pages={2403–2406} }
 @article{arkun_reed_berkman_el-masry_zavada_reed_bedair_2004, title={Dependence of ferromagnetic properties on carrier transfer at GaMnN/GaN : Mg interface}, volume={85}, ISSN={["1077-3118"]}, DOI={10.1063/1.1810216}, abstractNote={We report on the dependence of ferromagnetic properties of metalorganic chemical vapor deposition grown GaMnN films on carrier transfer across adjacent layers. We found that the magnetic properties of GaMnN, as a part of GaMnN∕GaN:Mg heterostructures, depend on the thickness of both the GaMnN film and the adjacent GaN:Mg layer and on the presence of a wide band gap barrier at this interface. These results are explained based on the occupancy of the Mn energy band and how the occupancy can be altered due to carrier transfer at the GaMnN∕GaN:Mg interfaces.}, number={17}, journal={APPLIED PHYSICS LETTERS}, author={Arkun, FE and Reed, MJ and Berkman, EA and El-Masry, NA and Zavada, JM and Reed, ML and Bedair, SM}, year={2004}, month={Oct}, pages={3809–3811} }
 @article{reed_reed_jagannadham_verghese_bedair_el-masry_butler_2004, title={Electrical characterization of B-10 doped diamond irradiated with low thermal neutron fluence}, volume={22}, ISSN={["1520-8559"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-4344661941&partnerID=MN8TOARS}, DOI={10.1116/1.1763910}, abstractNote={A sample of B10 isotope doped diamond was neutron irradiated to a thermal fluence of 1.3×1019 neutron cm−2. The diamond sample was cooled continuously during irradiation in a nuclear reactor. Li7 is formed by nuclear transmutation reaction from B10. Characterization for electrical conductance in the temperature range of 160 K<T<600 K was performed on an unirradiated B10 doped sample and the B10 doped and irradiated sample. The unirradiated diamond sample showed p-type conductance at higher temperature (T>200 K) and p-type surface conductance at lower temperature (T<200 K). The irradiated sample showed decreasing conductance below 230 K and increasing conductance above 230 K with increasing temperature. Furthermore, the conductance showed a decrease above 400 K followed by an increase above 500 K. The observed behavior below 400 K with increase in temperature is interpreted in terms of compensation of surface p-type carriers by n-type bulk carriers generated from Li7 that is formed by nuclear transmutation reaction from B10 atoms. Also, compensation of n-type carriers from Li7 by p-type carriers from B10 is used to interpret the conductance above 400 K. A low concentration of radiation induced defects, absence of defect complexes, and the low activation energy of n-type Li7 are thought responsible for the observed variation of conductance in the irradiated diamond. The present results illustrate that neutron transmutation from B10 doped diamond is a useful method to achieve n-type conductivity in diamond.}, number={4}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Reed, ML and Reed, MJ and Jagannadham, K and Verghese, K and Bedair, SM and El-Masry, N and Butler, JE}, year={2004}, pages={1191–1194} }
 @article{moody_barletta_el-masry_roberts_aumer_leboeuf_bedair_2002, title={Effect of H-2 on nitrogen incorporation in the metalorganic chemical vapor deposition of GaAs1-yNy (0 <= y <= 0.08)}, volume={80}, ISSN={["0003-6951"]}, DOI={10.1063/1.1464225}, abstractNote={The effect of hydrogen on the incorporation of nitrogen in GaAs1−yNy grown by metalorganic chemical vapor deposition (MOCVD) is reported. Nitrogen content as high as y=0.081 has been achieved when the use of H2 is completely avoided in the MOCVD growth of GaAs1−yNy. When H2 is added to the growth ambient, the value of y in GaAs1−yNy decreases as the relative percent of H2 in the carrier gas increases. We will report on the properties of these GaAsN films and discuss the nature of the effect that H2 has on modulating the N content in these films.}, number={14}, journal={APPLIED PHYSICS LETTERS}, author={Moody, BF and Barletta, PT and El-Masry, NA and Roberts, JC and Aumer, ME and LeBoeuf, SF and Bedair, SM}, year={2002}, month={Apr}, pages={2475–2477} }
 @article{reed_el-masry_stadelmaier_ritums_reed_parker_roberts_bedair_2001, title={Room temperature ferromagnetic properties of (Ga, Mn)N}, volume={79}, ISSN={["1077-3118"]}, DOI={10.1063/1.1419231}, abstractNote={Dilute magnetic semiconductor GaN with a Curie temperature above room temperature has been achieved by manganese doping. By varying the growth and annealing conditions of Mn-doped GaN we have identified Curie temperatures in the range of 228–370 K. These Mn-doped GaN films have ferromagnetic behavior with hysteresis curves showing a coercivity of 100–500 Oe. Structure characterization by x-ray diffraction and transmission electron microscopy indicated that the ferromagnetic properties are not a result of secondary magnetic phases.}, number={21}, journal={APPLIED PHYSICS LETTERS}, author={Reed, ML and El-Masry, NA and Stadelmaier, HH and Ritums, MK and Reed, MJ and Parker, CA and Roberts, JC and Bedair, SM}, year={2001}, month={Nov}, pages={3473–3475} }
 @article{reed_ritums_stadelmaier_reed_parker_bedair_el-masry_2001, title={Room temperature magnetic (Ga,Mn)N: a new material for spin electronic devices}, volume={51}, ISSN={["0167-577X"]}, DOI={10.1016/S0167-577X(01)00342-1}, abstractNote={A new dilute magnetic semiconductor (Ga,Mn)N grown by metal organic chemical vapor deposition (MOCVD) is reported. Vibrating sample magnetometer (VSM) and extraordinary Hall effect (EHE) measurements verified a ferromagnetic component at room temperature. The direction of the easy axis and the Curie temperature varies with the growth conditions, the latter ranging from 38°C to 75°C. Secondary ion mass spectroscopy (SIMS) confirms diffusion of Mn into the GaN to a depth of 380 Å.}, number={6}, journal={MATERIALS LETTERS}, author={Reed, ML and Ritums, MK and Stadelmaier, HH and Reed, MJ and Parker, CA and Bedair, SM and El-Masry, NA}, year={2001}, month={Dec}, pages={500–503} }
 @article{el-masry_behbehani_leboeuf_aumer_roberts_bedair_2001, title={Self-assembled AlInGaN quaternary superlattice structures}, volume={79}, ISSN={["0003-6951"]}, DOI={10.1063/1.1400763}, abstractNote={When an AlInGaN quaternary alloy is grown by metalorganic chemical-vapor deposition under certain growth conditions, a self-assembled superlattice structure is obtained. The superlattice structure is made of quaternary layers with different AIN and InN compositions. Transmission electron microscopy data show that the superlattice periodicity is regular with an individual layer thickness that depends on the growth conditions. Secondary ion mass spectrometry measurements show that the layers’ composition alternate between high-AIN and InN content and low-AlN and-InN content, while the in-plane lattice constant remains constant for both layers. A model is presented as a preliminary effort to explain these results.}, number={11}, journal={APPLIED PHYSICS LETTERS}, author={El-Masry, NA and Behbehani, MK and LeBoeuf, SF and Aumer, ME and Roberts, JC and Bedair, SM}, year={2001}, month={Sep}, pages={1616–1618} }
 @article{alexson_bergman_nemanich_dutta_stroscio_parker_bedair_el-masry_adar_2001, title={Ultraviolet raman study of A(1)(LO) and E-2 phonons in InxGa1-xN alloys}, volume={89}, ISSN={["0021-8979"]}, DOI={10.1063/1.1330760}, abstractNote={We report on ultraviolet Raman spectroscopy of InxGa1−xN thin films grown on sapphire by metal-organic chemical vapor deposition. The A1(LO) and E2 phonon mode behavior was investigated over a large compositional range (0<x<0.50). Compelling evidence is presented for one-mode behavior for the A1(LO) phonon, and data suggestive of two-mode behavior are presented for the E2 phonon.}, number={1}, journal={JOURNAL OF APPLIED PHYSICS}, author={Alexson, D and Bergman, L and Nemanich, RJ and Dutta, M and Stroscio, MA and Parker, CA and Bedair, SM and El-Masry, NA and Adar, F}, year={2001}, month={Jan}, pages={798–800} }
 @article{reed_el-masry_parker_roberts_bedair_2000, title={Critical layer thickness determination of GaN/InGaN/GaN double heterostructures}, volume={77}, DOI={10.1063/1.1334361}, abstractNote={We report on the critical layer thickness of GaN/InxGa1−xN/GaN double heterostructures in the composition range 0<x<0.16. The evolution of the photoluminescence spectra and the electrical properties of the InxGa1−xN well were monitored as its thickness was increased for a given % InN. Due to compressive stress and possible quantum-size effects, the emission energy from thin InGaN wells is blueshifted relative to thicker wells of a given % InN. The transition from the blueshifted emission of strained InGaN to redshifted emission of relaxed InGaN is also accompanied by dramatic changes in film conductivity and mobility. The thickness at which the onset of relaxation occurs is deemed the critical layer thickness of the InxGa1−xN film.}, number={25}, journal={Applied Physics Letters}, author={Reed, M. J. and El-Masry, N. A. and Parker, C. A. and Roberts, J. C. and Bedair, S. M.}, year={2000}, pages={4121–4123} }
 @article{hunter_reed_el-masry_roberts_bedair_2000, title={Epitaxial Y2O3 films grown on Si(111) by pulsed-laser ablation}, volume={76}, ISSN={["0003-6951"]}, DOI={10.1063/1.126217}, abstractNote={Y 2 O 3 has a relatively high dielectric constant (13–17) leading to several potential applications. In this work, pulsed-laser deposition was used to grow epitaxial Y2O3 films on Si(111) substrates. Structural characterization indicated two-dimensional growth without the formation of an amorphous interfacial layer. Annealing in either Ar or O2 was found to induce an O2 diffusion reaction resulting in the formation of two interfacial amorphous layers. Electrical characterization by capacitance–voltage and current–voltage indicated that the as-grown samples were poor insulating films. Annealing the samples improved the electrical performance by lowering leakage currents and exhibiting inversion during capacitance–voltage testing. This epitaxial growth points toward the possibility of the heteroepitaxial growth of silicon on insulator device structures.}, number={14}, journal={APPLIED PHYSICS LETTERS}, author={Hunter, ME and Reed, MJ and El-Masry, NA and Roberts, JC and Bedair, SM}, year={2000}, month={Apr}, pages={1935–1937} }
 @article{liu_bedair_el-masry_2000, title={Mn-prelayer effects on the epitaxial growth of MnSb on (111)B GaAs by pulsed laser deposition}, volume={42}, ISSN={["0167-577X"]}, DOI={10.1016/s0167-577x(99)00170-6}, abstractNote={Ferromagnetic thin films of MnSb have been grown epitaxially on (111)B GaAs substrate by pulsed laser deposition. The epitaxial growth was achieved by either depositing Mn/Sb multilayers or direct ablation of a Mn50Sb50 alloy target. The epitaxial growth occurs with (0001) of the MnSb film parallel to (111) of GaAs, with [011̄1] of MnSb 4° off [200] of the GaAs substrate, as determined from selected area diffraction (SAD). The easy magnetization in these films lies in the basal plane with coercivities, which vary from 40 to 110 Oe measured by Vibrating Sample Magnetometry (VSM). A Mn prelayer was important for high quality MnSb epitaxial growth with the c-axis perpendicular to the substrate surface. Films with an Sb prelayer or without Mn as a prelayer resulted in polycrystalline growth of MnSb. The mechanism of how the Mn prelayer facilitates the MnSb epitaxial growth is discussed in terms of two models.}, number={1-2}, journal={MATERIALS LETTERS}, author={Liu, SX and Bedair, SM and El-Masry, NA}, year={2000}, month={Jan}, pages={121–129} }
 @article{reed_liu_roberts_stadelmaier_bedair_el-masry_2000, title={The planar Hall effect in MnSb films and MnSb-based multilayer structures grown on (111)B GaAs}, volume={218}, ISSN={["0304-8853"]}, DOI={10.1016/S0304-8853(00)00403-0}, abstractNote={We report on the planar Hall effect properties of ferromagnetic MnSb films in ferromagnetic/nonmagnetic multilayer structures. We demonstrate an enhancement of the relative planar Hall resistivity when MnSb is used in multilayer structures. In single-layer MnSb films, the relative planar Hall resistivity is ∼2.5%, while the multilayer structures demonstrate up to ∼41% change. The following structures were prepared by pulsed laser deposition and grown on (1 1 1)B GaAs: epitaxial and polycrystalline MnSb thin films, MnSb/Bi multilayers and Mn/Sb/Mn/Bi multilayers. The multilayer structures also demonstrate temperature dependence, as the relative resistivity decreases to ∼30% when the temperature decreases to 100 K.}, number={2-3}, journal={JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS}, author={Reed, ML and Liu, SX and Roberts, JC and Stadelmaier, HH and Bedair, SM and El-Masry, NA}, year={2000}, month={Aug}, pages={177–181} }
 @article{johnson_yu_brown_koeck_el-masry_kong_edmond_cook_schetzina_1999, title={A critical comparison between MOVPE and MBE growth of III-V nitride semiconductor materials for opto-electronic device applications}, volume={4S1}, DOI={10.1557/s1092578300003100}, abstractNote={A systematic study of the growth and doping of GaN, AlGaN, and InGaN by both molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy (MOVPE) has been performed. Critical differences between the resulting epitaxy are observed in the p-type doping using magnesium as the acceptor species. MBE growth, using rf-plasma sources to generate the active nitrogen species for growth, has been used for III-Nitride compounds doped either n-type with silicon or p-type with magnesium. Blue and violet light emitting diode (LED) test structures were fabricated. These vertical devices required a relatively high forward current and exhibited high leakage currents. This behavior was attributed to parallel shorting mechanisms along the dislocations in MBE grown layers. For comparison, similar devices were fabricated using a single wafer vertical flow MOVPE reactor and ammonia as the active nitrogen species. MOVPE grown blue LEDs exhibited excellent forward device characteristics and a high reverse breakdown voltage. We feel that the excess hydrogen, which is present on the GaN surface due to the dissociation of ammonia in MOVPE, acts to passivate the dislocations and eliminate parallel shorting for vertical device structures. These findings support the widespread acceptance of MOVPE, rather than MBE, as the epitaxial growth technique of choice for III-V nitride materials used in vertical transport bipolar devices for optoelectronic applications.}, number={G5.10}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Johnson, M. A. L. and Yu, Z. H. and Brown, J. D. and Koeck, F. A. and El-Masry, N. A. and Kong, H. S. and Edmond, J. A. and Cook, J. W. and Schetzina, J. F.}, year={1999} }
 @article{parker_roberts_bedair_reed_liu_el-masry_1999, title={Determination of the critical layer thickness in the InGaN/GaN heterostructures}, volume={75}, ISSN={["0003-6951"]}, DOI={10.1063/1.125146}, abstractNote={We present an approach to determine the critical layer thickness in the InxGa1−xN/GaN heterostructure based on the observed change in the photoluminescence emission as the InxGa1−xN film thickness increases. From the photoluminescence data, we identify the critical layer thickness as the thickness where a transition occurs from the strained to unstrained condition, which is accompanied by the appearance of deep level emission and a drop in band edge photoluminescence intensity. The optical data that indicate the onset of critical layer thickness, was also confirmed by the changes in InxGa1−xN surface morphology with thickness, and is consistent with x-ray diffraction measurements.}, number={18}, journal={APPLIED PHYSICS LETTERS}, author={Parker, CA and Roberts, JC and Bedair, SM and Reed, MJ and Liu, SX and El-Masry, NA}, year={1999}, month={Nov}, pages={2776–2778} }
 @article{yu_johnson_brown_el-masry_muth_cook_schetzina_haberern_kong_edmond_1999, title={Epitaxial lateral overgrowth of GaN on SiC and sapphire substrates}, volume={4S1}, DOI={10.1557/s1092578300002878}, abstractNote={The epitaxial lateral overgrowth (ELO) process for GaN has been studied using SiC and sapphire substrates. Both MBE and MOVPE growth processes were employed in the study. The use of SiO2 versus SiNx insulator stripes was investigated using window/stripe widths ranging from 20 μm/4 μm to 3 μm/15 μm. GaN film depositions were completed at temperatures ranging from 800 °C to 1120 °C. Characterization experiments included RHEED, TEM, SEM and cathodolumenescence studies. The MBE growth experiments produced polycrystalline GaN over the insulator stripes even at deposition temperatures as high as 990 °C. In contrast, MOVPE growth produced single-crystal GaN stripes with no observable threading dislocations.}, number={G4.3}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Yu, Z. H. and Johnson, M. A. L. and Brown, J. D. and El-Masry, N. A. and Muth, J. F. and Cook, J. W. and Schetzina, J. F. and Haberern, K. W. and Kong, H. S. and Edmond, J. S.}, year={1999} }
 @article{venkatasubramanian_colpitts_b o'quinn_liu_el-masry_lamvik_1999, title={Low-temperature organometallic epitaxy and its application to superlattice structures in thermoelectrics}, volume={75}, ISSN={["0003-6951"]}, DOI={10.1063/1.124610}, abstractNote={We describe a simple, yet phenomenologically very different, low-temperature modification to the conventional metal–organic chemical vapor deposition. It has been applied to the epitaxy of hexagonal-phased Bi2Te3/Sb2Te3 superlattices on zinc-blende GaAs substrates. The modification enables a two-dimensional, layer-by-layer, epitaxy instead of a three-dimensional islanded growth. Therefore, this approach is of generic importance to the epitaxy of many electronic and magnetic materials and their superlattices. High-resolution transmission electron microscopy studies indicate that the interface between the GaAs substrate and Bi2Te3 film is qualitatively defect free and that periodic structures are formed in the Bi2Te3/Sb2Te3 superlattices, with one of the individual layers as small as 10 Å. Such ultra-short-period superlattices offer significantly higher carrier mobilities than their respective solid-solution alloys, apparently due to the elimination of alloy scattering and the minimal effects of random interface scattering on carrier transport. This represents one of the successful observations of enhanced carrier mobilities in monolayer-range superlattices.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Venkatasubramanian, R and Colpitts, T and B O'Quinn and Liu, S and El-Masry, N and Lamvik, M}, year={1999}, month={Aug}, pages={1104–1106} }
 @article{robins_paul_parker_roberts_bedair_piner_el-masry_1999, title={Optical absorption, Raman, and photoluminescence excitation spectroscopy of inhomogeneous InGaN films}, volume={4S1}, DOI={10.1557/s1092578300002490}, abstractNote={InxGa1−xN films with x=0.06 to x=0.49 were characterized by optical transmittance, Raman, and photoluminescence excitation spectroscopies. Previous microstructural characterizations detected phase separation only in films with x>0.2. The transmittance data suggest that compositional inhomogeneity is also present in the lower-x films (x<0.2). Both Raman and photoluminescence excitation spectra show features that correlate with compositional inhomogeneity and phase separation in the films with x>0.2. The composition dependence of the Raman spectra, from x=0.28 to x=0.49, is consistent with an increase in the size of the phase-separated regions with increasing x.}, number={G3.22}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Robins, L. H. and Paul, A. J. and Parker, C. A. and Roberts, J. C. and Bedair, S. M. and Piner, E. L. and El-Masry, N. A.}, year={1999} }
 @article{parker_roberts_bedair_reed_liu_el-masry_robins_1999, title={Optical band gap dependence on composition and thickness of InxGa1-xN (0 < x < 0.25) grown on GaN}, volume={75}, ISSN={["1077-3118"]}, DOI={10.1063/1.125079}, abstractNote={Band gap measurements have been carried out in strained and relaxed InxGa1−xN epilayers with x<0.25. Values of x were determined from x-ray diffraction of relaxed films. The lowest energy absorption threshold, measured by transmittance, was found to occur at the same energy as the peak of the photoluminescence spectrum. Bowing parameters for both strained and relaxed films were determined to be 3.42 and 4.11 eV, respectively. The dependence of the band gap shift, ΔEg, on strain is presented.}, number={17}, journal={APPLIED PHYSICS LETTERS}, author={Parker, CA and Roberts, JC and Bedair, SM and Reed, MJ and Liu, SX and El-Masry, NA and Robins, LH}, year={1999}, month={Oct}, pages={2566–2568} }
 @article{behbehani_piner_liu_el-masry_bedair_1999, title={Phase separation and ordering coexisting in InxGa1-xN grown by metal organic chemical vapor deposition}, volume={75}, ISSN={["0003-6951"]}, DOI={10.1063/1.124964}, abstractNote={We have recently reported the occurrence of phase separation in InxGa1−xN samples with x>0.25. Theoretical studies have suggested that InxGa1−xN can phase-separate asymmetrically into a low InN% phase and an ordered high InN% phase. In this letter, we report on the existence of simultaneous phase separation and ordering of InxGa1−xN samples with x>0.25. In these samples, phase separation was detected by both transmission electron microscopy selected area diffraction (TEM-SAD) and x-ray diffraction. Ordering was detected by both imaging and TEM-SAD.}, number={15}, journal={APPLIED PHYSICS LETTERS}, author={Behbehani, MK and Piner, EL and Liu, SX and El-Masry, NA and Bedair, SM}, year={1999}, month={Oct}, pages={2202–2204} }
 @article{johnson_yu_brown_el-masry_cook_schetzina_1999, title={Scanning electron microscopy and cathodoluminescence study of the epitaxial lateral overgrowth (ELO) process for gallium nitride}, volume={28}, ISSN={["0361-5235"]}, DOI={10.1007/s11664-999-0030-1}, number={3}, journal={JOURNAL OF ELECTRONIC MATERIALS}, author={Johnson, MAL and Yu, ZH and Brown, JD and El-Masry, NA and Cook, JW and Schetzina, JF}, year={1999}, month={Mar}, pages={295–300} }
 @misc{mcintosh_bedair_el-masry_roberts_1998, title={Methods of forming indium gallium nitride or aluminum indium gallium nitride using controlled hydrogen gas flow}, volume={5,851,905}, number={1998 Dec. 22}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={McIntosh, F. G. and Bedair, S. M. and El-Masry, N. A. and Roberts, J. C.}, year={1998}, month={Dec} }
 @article{johnson_brown_el-masry_cook_schetzina_kong_edmond_1998, title={Molecular beam epitaxy growth and properties of GaN, InGaN, and GaN/InGaN quantum well structures}, volume={16}, ISSN={["1071-1023"]}, DOI={10.1116/1.590000}, abstractNote={Growth of III–V nitrides by molecular beam epitaxy (MBE) was studied using rf nitrogen plasma sources. Plasma sources from three different vendors have been tested. All three of the sources have been used to grow high quality GaN. However, the EPI rf source produces an optical emission spectrum that is very rich in the active nitrogen species of 1st-positive excited nitrogen molecules and nitrogen atoms. GaN growth rates at 800 °C of 1 μm/h have been achieved using this source. The MBE-grown GaN films are deposited homoepitaxially on high quality metalorganic vapor phase epitaxy-grown GaN/SiC substrates. With the growth conditions for high quality undoped GaN as a base line, a detailed study of Mg doping for p-type GaN was performed. An acceptor incorporation of 2×1019 cm−3 was measured by both capacitance–voltage and secondary ion mass spectroscopy for a doping source temperature of 290 °C. However, a faceted three-dimensional growth mode was observed by reflection high energy electron diffraction during Mg doping of GaN. Additional studies suggest an interdependence between Mg incorporation and growth surface morphology. Quantum well structures made from the InGaN ternary alloy were grown using a modulated beam MBE method. With this technique, quantum well compositions were controllable, grown with visible luminescence ranging from 400 to 515 nm depending on indium mole fraction. Light emitting diode test structures, combining Mg p-type doping with InGaN quantum wells, were fabricated and tested.}, number={3}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B}, author={Johnson, MAL and Brown, JD and El-Masry, NA and Cook, JW and Schetzina, JF and Kong, HS and Edmond, JA}, year={1998}, pages={1282–1285} }
 @article{yu_johnson_brown_el-masry_cook_schetzina_1998, title={Study of the epitaxial-lateral-overgrowth (ELO) process for GaN on sapphire}, volume={195}, ISSN={["0022-0248"]}, DOI={10.1016/S0022-0248(98)00638-1}, abstractNote={Growth of GaN by MOVPE on mismatched substrates such as sapphire and SiC produces a columnar material consisting of many hexagonal grains ∼0.2–1.0 μm in diameter. However, the epitaxial–lateral-overgrowth (ELO) process for GaN creates a new material – single-crystal GaN. We have studied the ELO process using a MOVPE reactor featuring vertical gas flows and fast substrate rotation to synthesize GaN ELO samples. Characterization experiments consisted of plan-view scanning electron microscopy and vertical-cross-section transmission electron microscopy studies, which disclosed a large reduction in dislocations in the ELO regions of the GaN samples. Panchromatic and monochromatic cathodoluminescence images and spectra were employed to study the spatial variation of the optical properties of the GaN ELO samples.}, number={1-4}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Yu, ZH and Johnson, MAL and Brown, JD and El-Masry, NA and Cook, JW and Schetzina, JF}, year={1998}, month={Dec}, pages={333–339} }
 @article{piner_behbehani_elmasry_mcintosh_roberts_boutros_bedair_1997, title={Effect of hydrogen on the indium incorporation in InGaN epitaxial films}, volume={70}, ISSN={["0003-6951"]}, DOI={10.1063/1.118181}, abstractNote={The InN percent in metalorganic chemical vapor deposition (MOCVD) and atomic layer epitaxy (ALE) grown InGaN was found to be significantly influenced by the amount of hydrogen flowing into the reactor. The temperature ranges for this study are 710–780 °C for MOCVD, and 650–700 °C for ALE. For a given set of growth conditions, an increase of up to 25% InN in InGaN, as determined by x-ray diffraction, can be achieved by reducing the hydrogen flow from 100 to 0 sccm. Additionally, the hydrogen produced from the decomposition of ammonia does not seem to change the InN percent in the films, indicating that the ammonia decomposition rate is less than 0.1%. The phenomenon of having hydrogen control the indium incorporation was not reported in the growth of any other III–V compound previously studied.}, number={4}, journal={APPLIED PHYSICS LETTERS}, author={Piner, EL and Behbehani, MK and ElMasry, NA and McIntosh, FG and Roberts, JC and Boutros, KS and Bedair, SM}, year={1997}, month={Jan}, pages={461–463} }
 @article{mcintosh_piner_roberts_behbehani_aumer_elmasry_bedair_1997, title={Epitaxial deposition of GaInN and InN using the rotating susceptor ALE system}, volume={112}, ISSN={["0169-4332"]}, DOI={10.1016/S0169-4332(96)00992-0}, abstractNote={The growth of GaInN ternary alloys has been investigated using atomic layer epitaxy. Single crystal films have been deposited at 100 Torr in the 600°C to 700°C temperature range using the rotating susceptor approach. The InN percentage in the deposited films were found to depend on more than just the gas phase In/Ga ratio. In addition to the relative indium to gallium composition of the precursor gases, the indium incorporation was also found to depend on the absolute partial pressures of the reactant gases. The indium incorporation increases with decreasing growth temperatures, and may reach a temperature dependent saturation limit for a given set of growth conditions. Optimization of the ALE growth process has resulted in single crystal films exhibiting band edge room temperature photoluminescence for InN percentages of up to 27% in the GaInN ternary films. In addition, single crystal indium nitride has been grown using the ALE technique at 480°C.}, journal={APPLIED SURFACE SCIENCE}, author={McIntosh, FG and Piner, EL and Roberts, JC and Behbehani, MK and Aumer, ME and ElMasry, NA and Bedair, SM}, year={1997}, month={Mar}, pages={98–101} }
 @article{bedair_mcintosh_roberts_piner_boutros_elmasry_1997, title={Growth and characterization of In-based nitride compounds}, volume={178}, ISSN={["0022-0248"]}, DOI={10.1016/S0022-0248(97)00069-9}, abstractNote={Development of In-based nitride compounds is lagging behind the corresponding Al- and Ga-based compounds. Potential problems facing the growth of Inx Ga1 − x N films and their double heterostructures will be outlined. A tentative model which describes the reaction pathways taking place during the growth of these In-based nitride compounds is presented and is used to explain both our ALE and MOCVD results. In addition, growth parameters leading to the achievement of high values of x, reduction of In metal incorporation and improvement of both the structural and optical properties of InGaN, AlGaInN and InN will be discussed. Properties of AlGaN/InGaN/AlGaN and AlGaInN/InGaN/AlGaInN double heterostructures will be presented, with emission wavelengths in the 400–550 nm range.}, number={1-2}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Bedair, SM and McIntosh, FG and Roberts, JC and Piner, EL and Boutros, KS and ElMasry, NA}, year={1997}, month={Jun}, pages={32–44} }
 @article{piner_behbehani_elmasry_roberts_mcintosh_bedair_1997, title={Impurity dependence on hydrogen and ammonia flow rates in InGaN bulk films}, volume={71}, ISSN={["0003-6951"]}, DOI={10.1063/1.119775}, abstractNote={H, C, and O impurity concentrations in metalorganic chemical vapor deposition grown InGaN were found to be dependent on the hydrogen and NH3 flow rates. By increasing the hydrogen flow rate from 0 to 100 sccm, a decrease of greater than two orders of magnitude in the C and O impurity levels and one order of magnitude in the H impurity level was observed. Increasing the NH3 flow rate from 1 to 5 slm results in a decrease in the C concentration and an increase in the H and O concentrations indicating that high purity NH3 (99.999%) can be a significant source of O contamination. Additional studies show that when the InN percent in the InGaN films increases, the impurity concentrations increase regardless of changes in the growth conditions. The InGaN films were grown from 710 to 780 °C and the impurity concentrations were characterized by secondary ion mass spectrometry.}, number={14}, journal={APPLIED PHYSICS LETTERS}, author={Piner, EL and Behbehani, MK and ElMasry, NA and Roberts, JC and McIntosh, FG and Bedair, SM}, year={1997}, month={Oct}, pages={2023–2025} }
 @article{johnson_fujita_rowland_bowers_hughes_he_elmasry_cook_schetzina_ren_et al._1997, title={MBE growth and properties of GaN on GaN/SiC substrates}, volume={41}, ISSN={["0038-1101"]}, DOI={10.1016/S0038-1101(96)00169-4}, abstractNote={Abstract Growth of III–V nitrides by molecular beam epitaxy (MBE) is being studied at NCSU using an r.f. nitrogen plasma source. GaN SiC substrates consisting of ∼ 3 μm thick GaN buffer layers grown on 6HSiC wafers by MOVPE at Cree Research Inc. are being used as substrates in the MBE film growth experiments. The MBE-grown GaN films exhibit excellent structural and optical properties—comparable to the best GaN films grown by MOVPE—as determined from photoluminescence, X-ray diffraction, and vertical-cross-section TEM micrographs. Mg and Si have been used as dopants for p -type and n -type layers, respectively. Al x Ga 1 − x N films ( x ∼ 0.06-0.08) and Al x Ga 1 − x N GaN multi-quantum-well structures have been grown which display good optical properties. Light-emitting diodes based on double-heterostructures of Al x Ga 1 − x N GaN which emit violet light at ∼400 nm have also been demonstrated. Growth of GaN on LiGaO 2 substrates is also reported for comparison.}, number={2}, journal={SOLID-STATE ELECTRONICS}, author={Johnson, MAL and Fujita, S and Rowland, WH and Bowers, KA and Hughes, WC and He, YW and ElMasry, NA and Cook, JW and Schetzina, JF and Ren, J and et al.}, year={1997}, month={Feb}, pages={213–218} }
 @article{venkatasubramanian_colpitts_watko_lamvik_elmasry_1997, title={MOCVD of Bi2Te3, Sb2Te3 and their superlattice structures for thin-film thermoelectric applications}, volume={170}, ISSN={["0022-0248"]}, DOI={10.1016/S0022-0248(96)00656-2}, abstractNote={The characteristics of metalorganic chemical vapor deposition (MOCVD) of Bi2Te3, Sb2Te3 and their superlattice structures are discussed in this paper. We have grown c-oriented films on both hexagonal sapphire and fcc GaAs substrates, with specular morphology and occasional stacking faults. Single crystallinity was confirmed by X-ray diffraction and low-energy electron diffraction (LEED). The stoichiometry (Bi:Te = 2:3, Sb:Te = 2:3) of the films were confirmed by X-ray photo-emission spectroscopy (XPS) and Rutherford back-scattering. We have also attempted to grow short-period (∼ 10 to 80 Å) superlattice structures in the Bi2Te3Sb2Te3 materials system. X-ray diffraction data indicating the quality of these layered structures is presented. The advantages offered by the nature of chemical bonding in these materials, along the growth direction, for obtaining abrupt interfaces is discussed. The electrical transport properties of the MOCVD-grown p-type Bi2Te3Sb2Te3 structures and other thermoelectric properties including thermal conductivity and Seebeck coefficient are discussed. The initial results on the performance parameter known as figure-of-merit of the superlattice structures, measured parallel to the plane of the superlattice interfaces, are significantly higher than in conventional bulk materials. These initial results suggest a significant potential for MOCVD-based materials technology for high-performance, thin-film, thermoelectric refrigeration.}, number={1-4}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Venkatasubramanian, R and Colpitts, T and Watko, E and Lamvik, M and ElMasry, N}, year={1997}, month={Jan}, pages={817–821} }
 @misc{mcintosh_bedair_el-masry_roberts_1997, title={Stacked quantum well aluminum indium gallium nitride light emitting diodes}, volume={5,684,309}, number={1997 Nov. 4}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={McIntosh, F. G. and Bedair, S. M. and El-Masry, N. A. and Roberts, J. C.}, year={1997}, month={Nov} }
 @article{elmasry_hussien_fahmy_karam_bedair_1992, title={CRITERION FOR SUPPRESSING WAFER BOW IN HETEROSTRUCTURES BY SELECTIVE EPITAXY}, volume={14}, ISSN={["0167-577X"]}, DOI={10.1016/0167-577x(92)90105-s}, abstractNote={Abstract One problem heteroepitaxial growth faces is the mismatch of thermal expansion coefficients. This mismatch causes bowing in the wafer during cooling down after the growth, which interferes with device fabrication especially the photolithographic processes. Selective epitaxy is found to be effective in eliminating wafer bow and it was experimentally achieved. In this work we develop a model based on basic principles of elasticity theory to predict the bow and to establish a criterion to eliminate this bow by selective epitaxy. It is found that the model is in agreement with our published experimental results in the case of selective epitaxy of GaAs on Si.}, number={1}, journal={MATERIALS LETTERS}, author={ELMASRY, NA and HUSSIEN, SA and FAHMY, AA and KARAM, NH and BEDAIR, SM}, year={1992}, month={Jun}, pages={58–62} }
 @article{hussien_fahmy_elmasry_bedair_1990, title={A CRITERION FOR THE SUPPRESSION OF PLASTIC-DEFORMATION IN LASER-ASSISTED CHEMICAL VAPOR-DEPOSITION OF GAAS}, volume={67}, ISSN={["0021-8979"]}, DOI={10.1063/1.345033}, abstractNote={Laser-induced chemical vapor deposition (LCVD) of GaAs allows deposited film to trace the path of the laser beam, thus making it attractive for several applications. However the localized thermal expansion resulting from the laser-induced temperature rise has to be elastically accomodated in order to prevent lattice defects in the LCVD film. We report on the growth conditions that can be allowed without the occurrence of plastic deformation in the epitaxial films. A model is presented to explain the thermal expansion induced distortion during the deposition process and is compared with experimental results.}, number={8}, journal={JOURNAL OF APPLIED PHYSICS}, author={HUSSIEN, SA and FAHMY, AA and ELMASRY, NA and BEDAIR, SM}, year={1990}, month={Apr}, pages={3853–3857} }
 @misc{stadelmaier_el-masry_1988, title={Method of producing high performance permanent magnets}, volume={RE32,714}, number={1988 Jul. 29}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Stadelmaier, H. H. and El-Masry, N. A.}, year={1988} }
 @misc{stadelmaier_el-masry_1985, title={Method of producing high performance permanent magnets}, volume={4,541,877}, number={1985 Sep. 17}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Stadelmaier, H. H. and El-Masry, N. A.}, year={1985} }
 @inproceedings{emara_berkman_zavada_el-masry_bedair, title={Strain relaxation in InxGa1-xN/GaN quantum well structures}, volume={8}, number={7-8}, booktitle={Physica status solidi c: current topics in solid state physics, vol 8, no 7-8}, author={Emara, A. M. and Berkman, E. A. and Zavada, J. and El-Masry, N. A. and Bedair, S. M.} }
 @misc{elmasry_bedair_reed_stadelmaier, title={Transition metal doped ferromagnetic III-V nitride material films and methods of fabricating the same}, volume={6,955,858}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={ElMasry, N. A. and Bedair, S. M. and Reed, M. L. and Stadelmaier, H.} }