@misc{piner_rajagopal_roberts_linthicum_2008, title={Gallium nitride material structures including substrates and methods associated with the same}, volume={7,365,374}, number={2008 Apr. 29}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Piner, E. L. and Rajagopal, P. and Roberts, J. C. and Linthicum, K. J.}, year={2008} }
 @misc{nagy_borges_brown_chaudhari_cook_hanson_johnson_linthicum_piner_rajagopal_et al._2008, title={Gallium nitride material transistors and methods associated with the same}, volume={7,352,016}, number={2008 Apr. 1}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Nagy, W. H. and Borges, R. M. and Brown, J. D. and Chaudhari, A. D. and Cook, J. W. and Hanson, A. W. and Johnson, J. W. and Linthicum, K. J. and Piner, E. L. and Rajagopal, P. and et al.}, year={2008} }
 @misc{johnson_piner_linthicum_2008, title={Semiconductor device-based sensors}, volume={7,361,946}, number={2008 Apr. 22}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Johnson, J. W. and Piner, E. L. and Linthicum, K. J.}, year={2008} }
 @article{al-ajmi_kolbas_roberts_rajagopal_cook_piner_linthicum_2008, title={Stimulated emission and lasing from an Al0.13Ga0.87N/GaN double heterostructure grown on a silicon substrate}, volume={92}, number={2}, journal={Applied Physics Letters}, author={Al-Ajmi, F. S. and Kolbas, R. M. and Roberts, J. C. and Rajagopal, P. and Cook, J. W. and Piner, E. L. and Linthicum, K. J.}, year={2008} }
 @article{al-ajmi_kolbas_roberts_rajagopal_cook_piner_linthicum_2007, title={Room temperature laser action from multiple bands in photoexcited GaN grown on a silicon substrate}, volume={90}, number={15}, journal={Applied Physics Letters}, author={Al-Ajmi, F. S. and Kolbas, R. M. and Roberts, J. C. and Rajagopal, P. and Cook, J. W. and Piner, E. L. and Linthicum, K. J.}, year={2007} }
 @misc{weeks_piner_borges_linthicum_2003, title={Gallium nitride material devices and methods including backside vias}, volume={6,611,002}, number={2003 Aug. 26}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Weeks, T. W. and Piner, E. L. and Borges, R. M. and Linthicum, K. J.}, year={2003} }
 @misc{weeks_piner_gehrke_linthicum_2003, title={Gallium nitride materials and methods}, volume={6,649,287}, number={2003 Nov. 18}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Weeks, T. W. and Piner, E. L. and Gehrke, T. and Linthicum, K. J.}, year={2003} }
 @article{liliental-weber_benamara_washburn_domagala_bak-misiuk_piner_roberts_bedair_2001, title={Relaxation of InGaN thin layers observed by x-ray and transmission electron microscopy studies}, volume={30}, ISSN={["0361-5235"]}, DOI={10.1007/s11664-001-0056-5}, number={4}, journal={JOURNAL OF ELECTRONIC MATERIALS}, author={Liliental-Weber, Z and Benamara, M and Washburn, J and Domagala, JZ and Bak-Misiuk, J and Piner, EL and Roberts, JC and Bedair, SM}, year={2001}, month={Apr}, pages={439–444} }
 @article{joshkin_parker_bedair_muth_shmagin_kolbas_piner_molnar_1999, title={Effect of growth temperature on point defect density of unintentionally doped GaN grown by metalorganic chemical vapor deposition and hydride vapor phase epitaxy}, volume={86}, ISSN={["0021-8979"]}, DOI={10.1063/1.370727}, abstractNote={We report on the investigation of the effect of growth temperature on point defect density of unintentionally doped GaN grown by atmospheric pressure metalorganic chemical vapor deposition and hydride vapor phase epitaxy. A correlation between photoluminescence (PL) spectra and the concentration of donors and acceptors in unintentionally doped GaN is presented. The effects of oxygen and native acceptors on the electrical and optical properties of GaN epitaxial layers are discussed and a classification of PL data is presented. On this basis we show that oxygen creates a shallow donor in GaN with an activation energy of about 23.5±1 meV. We determine that the concentration of native acceptors in GaN increases with an increase in growth temperature. These native acceptors, probably gallium antisites (GaN) and/or gallium vacancies (VGa), are nonradiative defects. We show that a second donor level in GaN has an activation energy of about 52.5±2.5 meV and produces a PL peak with an energy of about 3.45 eV at low temperatures. From Hall investigations we show that a third donor in GaN has an activation energy of 110±10 meV.}, number={1}, journal={JOURNAL OF APPLIED PHYSICS}, author={Joshkin, VA and Parker, CA and Bedair, SM and Muth, JF and Shmagin, IK and Kolbas, RM and Piner, EL and Molnar, RJ}, year={1999}, month={Jul}, pages={281–288} }
 @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={In x Ga 1−x N 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{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{el-masry_piner_liu_bedair_1998, title={Phase separation in InGaN grown by metalorganic chemical vapor deposition}, volume={72}, ISSN={["0003-6951"]}, DOI={10.1063/1.120639}, abstractNote={We report on phase separation in thick InGaN films with up to 50% InN grown by metalorganic chemical vapor deposition from 690 to 780 °C. InGaN films with thicknesses of 0.5 μm were analyzed by θ–2θ x-ray diffraction, transmission electron microscopy (TEM), and selected area diffraction (SAD). Single phase InGaN was obtained for the as-grown films with <28% InN. However, for films with higher than 28% InN, the samples showed a spinodally decomposed microstructure as confirmed by TEM and extra spots in SAD patterns that corresponded to multiphase InGaN.}, number={1}, journal={APPLIED PHYSICS LETTERS}, author={El-Masry, NA and Piner, EL and Liu, SX and Bedair, SM}, year={1998}, month={Jan}, pages={40–42} }
 @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{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{joshkin_roberts_mcintosh_bedair_piner_behbehani_1997, title={Optical memory effect in GaN epitaxial films}, volume={71}, ISSN={["0003-6951"]}, DOI={10.1063/1.120414}, abstractNote={We report on memory effects in the optical properties of GaN and AlN epitaxial-films grown by atmospheric pressure metal organic chemical vapor deposition. After exposing selected areas of particular samples with He–Cd laser light (3.8 eV), we observed a persistent and marked decrease in the near band edge photoluminescence (PL) intensity emitted from these areas. This effect has been observed in epitaxial films that typically have a pyramidlike hillock surface. This ability to modulate PL emission intensity at individual points in these materials can be exploited as a method for optical data storage. A means of erasing information stored using this effect has also been investigated using lower energy (∼2 eV).}, number={2}, journal={APPLIED PHYSICS LETTERS}, author={Joshkin, VA and Roberts, JC and McIntosh, FG and Bedair, SM and Piner, EL and Behbehani, MK}, year={1997}, month={Jul}, pages={234–236} }
 @article{zeng_smith_lin_jiang_roberts_piner_mcintosh_1997, title={Optical transitions in InGaN/AlGaN single quantum wells}, volume={15}, number={4}, journal={Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures}, author={Zeng, K. C. and Smith, M. and Lin, J. Y. and Jiang, H. X. and Roberts, John C. and Piner, E. L. and McIntosh, F. G.}, year={1997}, pages={1139–1143} }