@article{zheleva_lelis_duscher_liu_levin_das_2008, title={Transition layers at the SiO2/SiC interface}, volume={93}, number={2}, journal={Applied Physics Letters}, author={Zheleva, T. and Lelis, A. and Duscher, G. and Liu, F. and Levin, I. and Das, M.}, year={2008} }
 @misc{zheleva_thomson_smith_linthicum_gehrke_davis_2007, title={Methods of fabricating gallium nitride semiconductor layers by lateral growth into trenches}, volume={7,195,993}, number={2007 Mar. 27}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Zheleva, T. and Thomson, D. B. and Smith, S. A. and Linthicum, K. J. and Gehrke, T. and Davis, R. F.}, year={2007} }
 @misc{zheleva_thomson_smith_linthicum_gehrke_davis_2005, title={Second gallium nitride layers that extend into trenches in first gallium nitride layers}, volume={6,897,483}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Zheleva, T. and Thomson, D. B. and Smith, S. A. and Linthicum, K. J. and Gehrke, T. and Davis, R. F.}, year={2005} }
 @misc{davis_nam_zheleva_bremser_2003, title={Gallium nitride semiconductor structures including lateral gallium nitride layers}, volume={6,570,192}, number={2003 May 27}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Davis, R. F. and Nam, O.-H. and Zheleva, T. and Bremser, M. D.}, year={2003} }
 @misc{davis_nam_zheleva_bremser_2003, title={Methods of fabricating gallium nitride semiconductor layers by lateral overgrowth}, volume={6,602,763}, number={2003 Aug. 5}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Davis, R. F. and Nam, O.-H. and Zheleva, T. and Bremser, M. D.}, year={2003} }
 @article{zheleva_nam_ashmawi_griffin_davis_2001, title={Lateral epitaxy and dislocation density reduction in selectively grown GaN structures}, DOI={10.1016/S0022-0248(00)00832-0}, abstractNote={The results of a comparative study of the defect microstructures at different regions in epitaxial, monocrystalline GaN structures grown selectively within windows in and laterally over SiO2 masks deposited on GaN/AlN/6H–SiC heterostructures are presented. The defects in the GaN grown within the SiO2 windows were predominantly threading dislocations of mostly mixed character with Burgers vector b=1/3〈112̄3〉 and edge dislocations with b=1/3〈112̄0〉 with a density range of 109–1010 cm−2, as determined using transmission electron microscopy (TEM). The regions of lateral epitaxial overgrowth (LEO-GaN) contained short dislocation segments parallel to the interfacial planes, which were usually aligned parallel or nearly parallel to the 〈11̄00〉 or 〈112̄0〉 directions and with densities of ⩽106 cm−2. Specific morphologies exhibited by the LEO-GaN were determined to be associated with the mechanism of stress relaxation. Finite element analysis of these complex heterostructures showed that the accommodation of the mismatches in the coefficients of thermal expansion among the different phases in the heterostructures was manifest in the formation of the curved surfaces observed in cross-sectional TEM.}, number={4}, journal={Journal of Crystal Growth}, author={Zheleva, Tsvetanka S. and Nam, Ok-Hyun and Ashmawi, Waeil M. and Griffin, Jason D. and Davis, Robert F.}, year={2001}, month={Feb} }
 @misc{zheleva_thomson_smith_linthicum_gehrke_davis_2001, title={Methods of fabricating gallium nitride semiconductor layers by lateral growth from sidewalls into trenches, and gallium nitride semiconductor structures fabricated thereby}, volume={6,265,289}, number={2001 July 24}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Zheleva, T. and Thomson, D. B. and Smith, S. A. and Linthicum, K. J. and Gehrke, T. and Davis, R. F.}, year={2001} }
 @article{davis_gehrke_linthicum_zheleva_rajagopal_zorman_mehregany_2001, title={Pendeo-epitaxial growth and characterization of thin films of gallium nitride and related materials on SiC(0001) and si(111) substrates}, volume={92}, number={2}, journal={Zeitschrift fur MetallkundeAmerican Journal of Physiology}, author={Davis, R. F. and Gehrke, T. and Linthicum, K. J. and Zheleva, T. S. and Rajagopal, P. and Zorman, C. A. and Mehregany, M.}, year={2001}, pages={163–166} }
 @article{davis_gehrke_linthicum_zheleva_preble_rajagopal_zorman_mehregany_2001, title={Pendeo-epitaxial growth of thin films of gallium nitride and related materials and their characterization}, DOI={10.1016/S0022-0248(01)00836-3}, abstractNote={Monocrystalline GaN and AlxGa1−xN films have been grown via the pendeo-epitaxy (PE)1 technique with and without Si3N4 masks on GaN/AlN/6H-SiC(0 0 0 1) and GaN(0 0 0 1)/AlN(0 0 0 1)/3C-SiC(1 1 1)/Si(1 1 1) substrates using organometallic vapor phase deposition. Scanning and transmission electron microscopies were used to evaluate the external microstructures and the distribution of dislocations, respectively. The dislocation densities in the PE grown films were reduced at least five orders of magnitude relative to the initial GaN seed layers. Tilting to 0.2° in the portion of the coalesced GaN epilayers grown over the silicon nitride masks was observed via X-ray diffraction. Neither tilting nor low angle boundaries were observed within areas of coalescence in the material grown on substrates without the masks. The strong, low-temperature PL band-edge peak at 3.45 eV with a FWHM of 17 meV was comparable to that observed in PE GaN films grown on 6H-SiC(0 0 0 1). The band-edge in the GaN grown on AlN(0 0 0 1)/SiC(1 1 1)Si(1 1 1) substrates was shifted to a lower energy by 10 meV, indicative of a greater tensile stress.}, number={2-4}, journal={Journal of Crystal Growth}, author={Davis, Robert F. and Gehrke, T. and Linthicum, K.J. and Zheleva, T.S. and Preble, E.A. and Rajagopal, P. and Zorman, C.A. and Mehregany, M.}, year={2001}, month={May} }
 @article{davis_gehrke_linthicum_rajagopal_roskowski_zheleva_preble_zorman_mehregany_schwarz_et al._2001, title={Review of pendeo-epitaxial growth and characterization of thin films of GaN and AlGaN alloys on 6H-SiC(0001) and Si(111) substrates}, volume={6}, number={14}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Davis, R. F. and Gehrke, T. and Linthicum, K. J. and Rajagopal, P. and Roskowski, A. M. and Zheleva, T. and Preble, E. A. and Zorman, C. A. and Mehregany, M. and Schwarz, U. and et al.}, year={2001}, pages={1–16} }
 @article{davis_nam_zheleva_gehrke_linthicum_rajagopal_2000, title={Lateral- and pendeo-epitaxial growth and defect reduction in GaN thin films}, volume={338}, number={3}, journal={Materials Science Forum}, author={Davis, R. F. and Nam, O. H. and Zheleva, T. S. and Gehrke, T. and Linthicum, K. J. and Rajagopal, P.}, year={2000}, pages={1471–1476} }
 @article{davis_gehrke_linthicum_zheleva_rajagopal_zorman_mehregany_2000, title={Pendeo-epitaxial growth and characterization of GaN and related materials on (6H-SiC(0001) and Si(111) substrates}, volume={5}, number={2000}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Davis, R. F. and Gehrke, T. and Linthicum, K. J. and Zheleva, T. S. and Rajagopal, P. and Zorman, C. A. and Mehregany, M.}, year={2000}, pages={U46–57} }
 @article{hanser_nam_bremser_thomson_gehrke_zheleva_davis_1999, title={Growth, doping and characterization of epitaxial thin films and patterned structures of AlN, GaN, and AlxGa1−xN}, DOI={10.1016/S0925-9635(98)00341-0}, abstractNote={Advancements in the doping of GaN and AlxGa1−xN thin films, and the growth of GaN and AlxGa1−xN structures on patterned heterostructure substrates via metalorganic vapor phase epitaxy are reported. The acceptor-type behavior of Mg-doped GaN films grown in N2 diluents is presented. Net ionized impurity concentrations up to 8×1018 cm−3 and Hall mobilities up to ≈14 cm2 V−1 s−1 were measured for Mg-doped films grown in N2 in the as-grown condition. Donor and acceptor doping of AlxGa1−xN alloys was performed. Acceptor doping of AlxGa1−xN for x≤0.13 and donor doping for x≤0.58 were achieved for films deposited at 1100 °C. Lateral epitaxial overgrowth of GaN and AlxGa1−xN layers was investigated. The growth and coalescence of GaN and AlxGa1−xN stripes patterned in SiO2 and/or SiNx masks deposited on GaN, including aligned second lateral epitaxial overgrowth on initial laterally overgrown GaN layers, are discussed.}, number={2-5}, journal={Diamond and Related Materials}, author={Hanser, Andrew D and Nam, Ok-Hyun and Bremser, Michael D and Thomson, Darren B and Gehrke, Thomas and Zheleva, Tsvetanka S and Davis, Robert F}, year={1999}, month={Mar} }
 @article{zheleva_ashmawi_jones_1999, title={Pendeo-epitaxy versus lateral epitaxial overgrowth of GaN: A comparative study via finite element analysis}, volume={176}, number={1}, journal={Physica Status Solidi. A, Applications and Materials Science}, author={Zheleva, T. S. and Ashmawi, W. M. and Jones, K. A.}, year={1999}, pages={545–551} }
 @misc{zheleva_smith_thomson_linthicum_rajagopal_davis_1999, title={Pendeo-epitaxy: A new approach for lateral growth of gallium nitride films}, volume={28}, number={4}, journal={Journal of Electronic Materials}, author={Zheleva, T. S. and Smith, S. A. and Thomson, D. B. and Linthicum, K. J. and Rajagopal, P. and Davis, R. F.}, year={1999}, pages={L5–8} }
 @article{zheleva_smith_thomson_gehrke_linthicum_rajagopal_carlson_ashmawi_davis_1999, title={Pendeo-epitaxy: A new approach for lateral growth of gallium nitride structures}, volume={4S1}, number={G3.38}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Zheleva, T. S. and Smith, S. A. and Thomson, D. B. and Gehrke, T. and Linthicum, K. J. and Rajagopal, P. and Carlson, E. and Ashmawi, W. M. and Davis, R. F.}, year={1999} }
 @article{linthicum_gehrke_thomson_tracy_carlson_smith_zheleva_zorman_mehregany_davis_1999, title={Process routes for low defect-density GaN on various substrates employing pendeo-epitaxial growth techniques}, volume={4S1}, number={G4.9}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Linthicum, K. J. and Gehrke, T. and Thomson, D. B. and Tracy, K. M. and Carlson, E. P. and Smith, T. P. and Zheleva, T. S. and Zorman, C. A. and Mehregany, M. and Davis, R. F.}, year={1999} }
 @article{feldermann_merk_hofsäss_ronning_zheleva_1999, title={Room temperature growth of cubic boron nitride}, DOI={10.1063/1.123613}, abstractNote={Boron nitride thin films were deposited at room temperature with various ion energies by mass selected ion beam deposition on cubic boron nitride (c-BN) previously nucleated on Si (100) substrates at a higher temperature. Selective area diffraction, electron energy loss, and infrared spectroscopy results reveal continued growth of the cubic phase. The reported temperature threshold of about 150 °C for c-BN film formation is therefore unmistakably related to the initial nucleation of c-BN, whereas the growth of c-BN appears to be temperature independent. The latter is in accordance with predictions of the cylindrical thermal spike growth model recently proposed by our group.}, number={11}, journal={Applied Physics Letters}, author={Feldermann, H. and Merk, R. and Hofsäss, H. and Ronning, C. and Zheleva, T.}, year={1999}, month={Mar} }
 @article{zheleva_ashmawi_nam_davis_1999, title={Thermal mismatch stress relaxation via lateral epitaxy in selectively grown GaN structures}, DOI={10.1063/1.123017}, abstractNote={A reduction in the dislocation density of 104–105 cm−2 has been achieved via lateral epitaxial overgrowth (LEO) of GaN films selectively grown from stripes etched in SiO2 masks deposited on GaN/AlN/6H–SiC(0001) heterostructures. The magnitudes and distribution of stresses generated in the LEO GaN layer and the SiO2, due primarily to differences in the coefficients of thermal expansion, were modeled using finite element (FE) analysis. These calculations showed that localized compressive stress fields of ≈3 GPa occurred at the edges of the LEO GaN in the vicinity of the GaN/SiO2 interface. Localized compression along the GaN substrate/SiO2 interface and tension along the 〈0001〉 direction were responsible for the change in shape of the SiO2 stripes from rectangular with flat sides to an airfoil shape with curved sides. The FE calculations also revealed that an increase in the width of the LEO GaN regions over the SiO2 or the reduction in the separation between the GaN stripes (all other dimensions being fixed) resulted in a slight reduction in the compressive stresses along the LEO GaN/SiO2 interface and an increase in the compressive stress along [0001]. An increase in the shear stress, at the corners of the LEO GaN near the LEO GaN/SiO2 interface, with an increase in the width of the LEO GaN region were also indicated.}, number={17}, journal={Applied Physics Letters}, author={Zheleva, Tsvetanka S. and Ashmawi, Waeil M. and Nam, Ok-Hyun and Davis, Robert F.}, year={1999}, month={Apr} }
 @article{hanser_wolden_perry_zheleva_carlson_banks_therrien_davis_1998, title={Analysis of reactor geometry and diluent gas flow effects on the metalorganic vapor phase epitaxy of AIN and GaN thin films on α(6H)-SiC substrates}, DOI={10.1007/s11664-998-0394-7}, number={4}, journal={Journal of Electronic Materials}, author={Hanser, A. D. and Wolden, C. A. and Perry, W. G. and Zheleva, T. and Carlson, E. P. and Banks, A. D. and Therrien, R. J. and Davis, R. F.}, year={1998}, month={Apr} }
 @article{perry_bremser_zheleva_linthicum_davis_1998, title={Biaxial strain in AlxGa1−xN/GaN layers deposited on 6H-SiC}, DOI={10.1016/S0040-6090(97)01217-0}, abstractNote={AlxGa1−xN/GaN multilayers (x≤0.12) deposited on AlN(0001) buffer layer/6H-SiC(0001) substrate combinations have been investigated using high resolution X-ray diffraction. Rocking curves (ω) showed that the AlxGa1−xN layers in the main contained a reduced dislocation density relative to the underlying GaN layers. The line widths of the radial scans (2θ−ω) of the AlxGa1−xN layers increased as the Al mole fraction increased due to alloy broadening. The in-plane lattice constant (a) of the AlxGa1−xN layer for each sample was equivalent to that of the GaN layer, indicating the layers were coherently strained. The strain in the AlGaN layer was tensile for each sample. This was determined using high-resolution reciprocal space maps of the (015) and (024) planes which revealed that the AlxGa1−xN and GaN lattice points had the same value of the in-plane components of the reciprocal lattice vector (S̄‖). For higher Al mole fractions, the samples were severely cracked, indicating the strain in the AlxGa1−xN layers exceeded critical values.}, number={1-2}, journal={Thin Solid Films}, author={Perry, William G and Bremser, M.B and Zheleva, T and Linthicum, K.J and Davis, R.F}, year={1998}, month={Jul} }
 @article{gruss_zheleva_davis_watkins_1998, title={Characterization of zirconium nitride coatings deposited by cathodic arc sputtering}, DOI={10.1016/S0257-8972(98)00584-2}, abstractNote={Polycrystalline ZrN coatings with a composition of 58.41 at.% Zr and 41.59 at.% N were deposited by cathodic arc evaporation on to Incoloy 825, Hastelloy C22 and Titanium Grade 12 metal substrates. Analyses of the coatings by scanning electron microscopy and Auger electron spectroscopy revealed the presence of 1–8-μm-diameter macroparticles composed of Zr metal. Compressive stresses of 4.06, 3.88 and 2.69 GPa were measured via X-ray diffraction in the coatings deposited on Inc., Hast. and Ti. substrates, respectively. Values for Young's modulus and hardness of 458 and 27.65 GPa, respectively, were obtained via nanoindentation. Studies of the interfacial chemistry via Auger electron spectroscopy and transmission electron microscopy revealed chemically abrupt interfaces and good compositional uniformity throughout the thickness of the zirconium nitride coatings.}, number={2-3}, journal={Surface and Coatings Technology}, author={Gruss, K.A. and Zheleva, T. and Davis, R.F. and Watkins, T.R.}, year={1998}, month={Sep} }
 @article{järrendahl_smith_zheleva_kern_davis_1998, title={Growth of highly (0001)-oriented aluminum nitride thin films with smooth surfaces on silicon carbide by gas-source molecular beam epitaxy}, DOI={10.1016/S0042-207X(97)00177-2}, abstractNote={Aluminum nitride thin films with very smooth surfaces have been grown by gas-source molecular beam epitaxy on 4H and 6H silicon carbide substrates. High purity ammonia was used as the nitrogen source in conjunction with Al evaporated from an effusion cell. Streaked reflection high energy electron diffraction patterns and reconstructions of the AlN surfaces indicated smooth films. This surface character was confirmed via atomic force microscopy and transmission electron microscopy which showed roughness root mean square values typically below 1 nm and very flat surfaces, respectively. X-ray diffraction showed the films to be highly c-axis oriented and single phase. Major impurities in the AlN films were oxygen and carbon, as revealed by secondary ion mass spectrometry.}, number={3}, journal={Vacuum}, author={Järrendahl, K and Smith, SA and Zheleva, T and Kern, RS and Davis, RF}, year={1998}, month={Mar} }
 @article{nam_zheleva_bremser_davis_1998, title={Lateral epitaxial overgrowth of GaN films on SiO2 areas via metalorganic vapor phase epitaxy}, DOI={10.1007/s11664-998-0393-8}, number={4}, journal={Journal of Electronic Materials}, author={Nam, Ok-Hyun and Zheleva, Tsvetanka S. and Bremser, Michael D. and Davis, Robert F.}, year={1998}, month={Apr} }
 @article{freitas_nam_zheleva_davis_1998, title={Optical and structural properties of lateral epitaxial overgrown GaN layers}, volume={190}, number={1998 June}, journal={Journal of Crystal Growth}, author={Freitas, J. A. and Nam, O. H. and Zheleva, T. S. and Davis, R. F.}, year={1998}, pages={92–96} }
 @article{kawaguchi_shimizu_yamaguchi_hiramatsu_sawaki_taki_tsuda_kuwano_oki_zheleva_et al._1998, title={The formation of crystalline defects and crystal growth mechanism in InxGa1-xN/GaN heterostructure grown by metalorganic vapor phase epitaxy}, volume={190}, number={1998 June}, journal={Journal of Crystal Growth}, author={Kawaguchi, Y. and Shimizu, M. and Yamaguchi, M. and Hiramatsu, K. and Sawaki, N. and Taki, W. and Tsuda, H. and Kuwano, N. and Oki, K. and Zheleva, T. and et al.}, year={1998}, pages={24–28} }
 @article{zheleva_nam_bremser_davis_1997, title={Dislocation density reduction via lateral epitaxy in selectively grown GaN structures}, DOI={10.1063/1.120091}, abstractNote={The microstructure and the lateral epitaxy mechanism of formation of homoepitaxially and selectively grown GaN structures within windows in SiO2 masks have been investigated by transmission electron microscopy (TEM) and scanning electron microscopy. The structures were produced by organometallic vapor phase epitaxy for field emission studies. A GaN layer underlying the SiO2 mask provided the crystallographic template for the initial vertical growth of the GaN hexagonal pyramids or striped pattern. The SiO2 film provided an amorphous stage on which lateral growth of the GaN occurred and possibly very limited compliancy in terms of atomic arrangement during the lateral growth and in the accommodation of the mismatch in the coefficients of thermal expansion during cooling. Observations with TEM show a substantial reduction in the dislocation density in the areas of lateral growth of the GaN deposited on the SiO2 mask. In many of these areas no dislocations were observed.}, number={17}, journal={Applied Physics Letters}, author={Zheleva, Tsvetanka S. and Nam, Ok-Hyun and Bremser, Michael D. and Davis, Robert F.}, year={1997}, month={Oct} }
 @article{bremser_perry_zheleva_edwards_nam_parikh_aspnes_davis_1997, title={Growth, doping and characterization of AlxGa1 − xN thin film alloys on 6H-SiC(0001) substrates}, volume={6}, DOI={10.1016/S0925-9635(96)00626-7}, abstractNote={Thin films of AlxGa1 − xN (0.05≤x≤0.96) having smooth surfaces were deposited directly on both vicinal and on-axis 6H-SiC(0001) substrates. Cross-sectional transmission electron microscopy of Al0.13Ga0.87N revealed stacking faults near the SiC/nitride alloy interface and numerous threading dislocations. Energy dispersive analysis, Auger electron spectroscopy (AES) and Rutherford backscattering were used to determine the compositions. These were paired with their respective cathodoluminescence (CL) near band-edge emission energies. A negative bowing parameter was determined. The CL emission energies were similar to the bandgap energies obtained by spectroscopic ellipsometry. Field emission AES of the initial growth of Al0.2Ga0.8N revealed an Al-rich layer near the interface. N-type (Si) doping was achieved for AlxGa1 − xN for 0.12≤x≤0.42.}, number={2-4}, journal={Diamond and Related Materials}, author={Bremser, M.D. and Perry, W.G. and Zheleva, T. and Edwards, N.V. and Nam, O.H. and Parikh, N. and Aspnes, D.E. and Davis, R.F.}, year={1997}, month={Mar}, pages={196–201} }
 @article{nam_bremser_zheleva_davis_1997, title={Lateral epitaxy of low defect density GaN layers via organometallic vapor phase epitaxy}, volume={71}, number={18}, journal={Applied Physics Letters}, author={Nam, O.-H. and Bremser, M. D. and Zheleva, T. S. and Davis, R. F.}, year={1997}, pages={2698–2640} }
 @article{edwards_yoo_bremser_zheleva_horton_perkins_weeks_liu_stall_kuech_et al._1997, title={Spectral analysis of above-, below-, and near-bandedge phenomena in GaN thin films}, volume={50}, DOI={10.1016/s0921-5107(97)00151-7}, abstractNote={We report spectroscopic ellipsometry (SE) and low-temperature reflectance data on epitaxial GaN thin film samples covering the widest range of tensile and compressive stress (−3.8–3.5 kbar) thus far. SE allows us to assess the preparation of smooth and abrupt GaN surfaces by chemical treatments in real time, and, coupled with the reflectance data, the E dn/dE contribution to dispersion, which is important for laser action. The reflectance data explicitly show the nonlinear behavior of the B–A and C–A splittings versus the energy of the A exciton. Lineshape ambiguities that hindered previous interpretations have been resolved with reciprocal space analysis, allowing us to obtain band parameters such as ΔSO=17.0±1 meV and ΔCF=9.8±1 meV with increased confidence.}, number={1-3}, journal={Materials Science and Engineering B}, author={Edwards, N.V and Yoo, S.D and Bremser, M.D and Zheleva, Ts and Horton, M.N and Perkins, N.R and Weeks, T.W, Jr and Liu, H and Stall, R.A and Kuech, T.F and et al.}, year={1997}, month={Dec}, pages={134–141} }
 @article{balkaş_sitar_zheleva_bergman_nemanich_davis_1997, title={Sublimation growth and characterization of bulk aluminum nitride single crystals}, DOI={10.1016/S0022-0248(97)00160-7}, abstractNote={Single crystalline platelets of aluminum nitride (AlN) ⩽ 1 mm thick have been grown within the temperature range of 1950–2250°C on 10 × 10 mm2 α(6H)-silicon carbide (SiC) substrates via sublimation-recondensation in a resistively heated graphite furnace. The source material was sintered AlN. A maximum growth rate of 500 μm/h was achieved at 2150°C and a source-to-seed separation of 4 mm. Growth rates below 2000°C were approximately one order of magnitude lower. Crystals grown at high temperatures ranged in color from blue to green due to the incorporation of Si and C from the SiC substrates; those grown at lower temperatures were colorless and transparent. Secondary-ion mass spectroscopy (SIMS) results showed almost a two order of magnitude decrease in the concentrations of these two impurities in the transparent crystals. Plan view transmission electron microscopy (TEM) of these crystals showed no line or planar defects. Raman spectroscopy and X-ray diffraction (XRD) studies indicated a strain free material.}, number={3-4}, journal={Journal of Crystal Growth}, author={Balkaş, Cengiz M. and Sitar, Zlatko and Zheleva, Tsvetanka and Bergman, L. and Nemanich, R. and Davis, R.F.}, year={1997}, month={Aug} }
 @article{hiramatsu_kawaguchi_shimizu_sawaki_zheleva_davis_tsuda_taki_kuwano_oki_1997, title={The composition pulling effect in MOVPE grown InGaN on GaN and AlGaN and its TEM characterization}, volume={2}, number={6}, journal={MRS Internet Journal of Nitride Semiconductor Research}, author={Hiramatsu, K. and Kawaguchi, Y. and Shimizu, M. and Sawaki, N. and Zheleva, T. S. and Davis, R. F. and Tsuda, H. and Taki, W. and Kuwano, N. and Oki, K.}, year={1997} }
 @inproceedings{balkas_sitar_zheleva_bergman_shmagin_muth_kolbas_nemanich_davis_1996, title={Growth of bulk AIN and GaN single crystals by sublimation}, booktitle={III-V nitrides: symposium held December 2-6, 1996, Boston, Massachusetts, U.S.A.  (Materials Research Society symposia proceedings ; v. 449)}, publisher={Pittsburgh, Pa.: Materials Research Society}, author={Balkas, C. M. and Sitar, Z. and Zheleva, T. and Bergman, L. and Shmagin, I. K. and Muth, J. F. and Kolbas, R. M. and Nemanich, R. and Davis, R. F.}, year={1996}, pages={41–46} }