以氮化鎵為基底的材料已成功應用於短波長雷射二極體，發光二極體及紫外光光檢測器。在本實驗中，我們已成功的使用有機金屬氣相沈積法把氮化鎵磊晶膜生長在三氧化二鋁基板上。並對生長氮化鎵磊晶膜前之氧化鋁基板預熱處理和氮化鎵緩衝層之生長溫度以及氮化鎵磊晶膜的生長溫度等參數進行研究。根據77K的光激發光譜、X光散射測量、掃瞄式電子顯微鏡的結果，瞭解氮化鎵的基本特性，並利用上述方式，生長更好的氮化鎵磊晶膜。在本實驗中，發現氧化鋁基板之預熱處理為影響單晶品質及表面平整度的重要參數。根據實驗的結果，我們針對黃光區及施體受體對的成因做了深入的研究及探討。

The materials based on GaN have successfully developed on short-wavelength laser diodes (LDs), light-emitting diodes (LEDs) and ultraviolet photodetector. In this study, GaN epitaxial layers have been successfully grown on sapphire substrates. We used several methods including the pre-baking treatment for sapphire substrates before growing epilayer, the growth temperature of buffer layer and the growth temperature of GaN epilayer to study it. From the results of the photoluminescence (PL) measured at 77K, the X-Ray diffraction measurement, SEM cross sectional views to realize the characteristic and we get a better qualities of GaN epilayers after using the foregoing methods. In this study, the pre-baking treatment for sapphire substrates can influence the quality and morphology of GaN epilayers. According to the results of the experiments, we study the mechanisms of yellows luminescence and donor-acceptor pair (DAP).

CONTENTS I
LIST OF FIGURES IV
ABSTRACT VII

1.INTRODUCTION 1
1.1 Evolutions and Applications of Ⅲ-Ⅴ compound Light EmittingDiode 1
1.2 Materials for Blue LEDs 5
1.2.1 SiC Blue LEDs 5
1.2.2 ZnSe Blue LEDs 6
1.2.3 GaN Blue LEDs 7
1.2.4 Blue Organic LEDs 9
1.3 Short Wavelength Light Emitting Diode Based on Ⅲ-Ⅴ
Nitride Materials 10
1.4 Growth for GaN-based Compound Semiconductors 12
(a) Considerations of the Appropriate Substrates 13
(b) Growth for p-type GaN 14

2.EXPERIMENTS 17
2.1 Growth System of MOCVD 17
2.1.1 Single Hot Zone and Cold Wall System 17
2.1.2 Simplicity, Flexibility and Versatility 18
2.1.3 Halide Free 18
2.1.4 Capability of Multiple Heterostructures 19
2.1.5 High Temperature 19
2.1.6 Low Pressure 19
2.2 Growth System Design 20
2.2.1 Gas Handling System 20
2.2.2 Reaction Chamber Design 21
2.2.3 Heating System 22
2.2.4 Exhausted System 22
2.2.5 Safety Equipment Considerations 23
2.3 Substrate Preparation 24
2.4 Growth Processes 24
2.5 Evaluation of GaN Epilayers 26

3.RESULTS AND DISCUSSION 27
3.1 Optical Properties of GaN Epilayers 27
3.2 Effect of Sapphire Pre-Baking at 1000℃ 29
3.2.1 PL Properties 29
3.2.2 X-Ray Measurements 30
3.2.3 SEM Analysis 30
3.3 Effect of Various Sapphire Pre-Baking Temperature 32
3.3.1 PL Properties 32
3.3.2 X-Ray Measurements 33
3.3.3 SEM Analysis 34
3.3.3 SIMS Depth Profiles and Analyses 34
3.4 Effect of Sapphire Pre-Baking at 1200℃ 37
3.4.1 PL Properties 37
3.4.2 X-Ray Measurements 38
3.4.3 SEM Analysis 38
3.5 Effect of the Flow Rate of TEGa 40
3.5.1 PL Properties 40
3.5.2 SEM Analysis 41
3.6 Effect of the Flow Rate of Ammonia 43
3.6.1 PL Properties 43
3.6.2 X-Ray Measurements 44
3.6.3 SEM Analysis 44
3.7 Effect of chamber pressure on GaN Growth 46
3.7.1 PL Properties 46
3.8 Effect of additional hydrogen on GaN growth 48
3.8.1 PL Properties 49
3.8.2 X-Ray Measurements 50
3.8.3 SEM Analysis 50
3.9 Effect of Various Sapphire Pre-Baking Temperature
(Growth Without Additional H2) 51
3.9.1 PL Properties 51
3.9.2 X-Ray Measurements 52
3.9.3 SEM Analysis 52
3.9.4 DCXD rocking curves Measurements 52
3.10 Effect of the Temperature of Nitridation and Buffer Layer 55
3.10.1 PL Properties 56
3.10.2 X-Ray Measurements 57
3.10.3 SEM Analysis 58
3.11 Growth Temperature of GaN Epilayer 59
3.11.1 PL Properties 59
3.11.2 X-Ray Measurements 60
3.11.3 SEM Analysis 61
3.12 Other Analyses in Our Experiments 62
3.12.1 X-Ray Measurements 62
3.12.2 AES Analysis 62
3.12.3 XPS Analysis 63
3.13 Possible Mechanisms of Yellow Luminescence 64
3.14 Mechanisms of DAP and YL in Our Experiments 66

4.CONCLUSIONS 68

REFERENCES 120

[1] J. Nishizawa, F. Sakurai, Y. Okuno, and K. Itoh, ”Blue-Light Emission from ZnSe P-N-Junctions,” Journal of Applied Physics, Vol. 57, Iss. 6, pp. 2210-2216, 1985
[2] K. Koga, and T. Yamaguchi, “Single-Crystals of SiC and Their Application to Blue LEDs,” Progress in Crystal Growth and Characterization of Materials, Vol. 23, pp. 127-151, 1991
[3] J. Edmond, H. Kong, and V. Dmitrieve, Institute of Physics Conference Series, Vol. 137, pp. 515, 1994
[4] A. Suzuki, M. Ikeda, N. Nagao, H. Matsunami, and T. Tanaka, “Liquid-Phase Epitaxial Growth of 6H-SiC by the Dipping Technique for Preparation of Blue-Light-Emitting Diodes,” Journal of Applied Physics, Vol. 47, pp. 4546-4550, 1976
[5] H. Matsunami, M. Ikeda, A. Suzuki, and T. Tanaka, “SiC Blue LED’s by Liquid-Phase Epitaxy,” IEEE Transactions on Electron Device, Vol. 24, pp. 958-960, 1977
[6] W. V. Munch and W. Kurzinger, “Silicon Carbide Blue-Emitting Diodes Produced by Liquid-Phase Epitaxy,“ Solid State Electronics, Vol. 21, pp. 1129-1132, 1978
[7] V. I. Levin, Y. M. Tairov, M. G. Travaxhdyan, F. Tsvekov, and M. A. Chernov, Soveit Physics Izvestia, Vol. 14, pp. 830, 1987
[8] Y. M. Tairov, and V. F. Tsvetkov, ”General-Principles of Growing Large-Size Single-Crystals of Various Silicon-Carbide Polytypes,“ Journal of Crystal Growth, Vol. 52, Iss. APR, pp. 146-150, 1981
[9] M. Ikeda, T. Hayakawa, S. Yamagiwa, H. Mastunami, and T. Tanaka, “Fabrication of 6H-SiC Light-Emitting Diodes by a Rotation Dipping Technique : Electroluminescence Mechaisms,” Journal of Applied Physics, Vol. 50, pp. 8215-8225, 1979
[10] Y. Chen, X. Liu, E. Weber, E. D. Bourret, Z. Lilientalweber, E. E. Haller, J. Washburn, D. J. Olego, D. R. Dorman, J. M. Gaines, and N. R. Tasker, “Structures and Electronic-Properties of Misfit Dislocations in ZnSe/GaAs(001) Heterojunctions,” Applied Physics Letters, Vol. 65, Iss. 5, pp. 549-551, 1994
[11] H. Mitsuhashi, I. Mitsuishi, M. Mizuta, and H. Kukimoto, “Coherent Growth of ZnSe on GaAs by MOCVD,” Japanese Journal of Applied Physics Part 2-Letters, Vol. 24, Iss. 8, pp. 578-580, 1985
[12] T. Ohtsuka, K. Horie, N. Akiyama, and T. Yao, ” Gas-Source Molecular-Beam Epitaxy of ZnSe Using Elemental Zn and Hydrogen Selenide,” Journal of Applied Physics, Vol. 78, Iss. 10, pp. 6006-6012, 1995
[13] M. Konagai, “Wide Band-Gap II-VI Compounds Grown by MOMBE,” Journal of Crystal Growth, Vol. 120, Iss. 1-4, pp. 261-268, 1992
[14] N. Matsumura, K. Maemura, T. Mori, and J. Saraie, ” Improvement in the Crystalline Quality of ZnSe(111) Films Grown by Molecular-Beam Epitaxy Using Misoriented GaAs(111)A Substrates,” Japanese Journal of Applied Physics Part 2-Letters, Vol. 34, Iss. 9A, pp. 1114-1116, 1995
[15] B. J. Wu, J. M. Depuydt, G. M. Haugen, G. E. Hofler, M. A. Haase, H. Cheng, S. Guha, J. Qiu, L. H. Kuo, and L. Salamancariba, “Wide-Band Gap Mgznsse Grown on (001) GaAs by Molecular-Beam Epitaxy,” Applied Physics Letters, Vol. 66, Iss. 25, pp. 3462-3464, 1995
[16] H. Hamadeh, J. Sollner, J. Schmoranzer, and M. Heuken, “Characterization of Zn-(1-Y)Mgysxse(1-X) Epilayers Grown by Low-Pressure Metalorganic Vapor-Phase Epitaxy,” Journal of Crystal Growth, Vol. 158, Iss. 1-2, pp. 89-96, 1996
[17] H. Okuyama, Y. Kishita, T. Miyajima, A. Ishibashi, and K. Akimoto, “Epitaxial-Growth of P-Type Znmgsse,“ Applied Physics Letters, Vol. 64, Iss. 7, pp. 904-906, 1994
[18] M. A. Haase, J. Qiu, J. M. Depuydt and H. Cheng, “Blue-Green Laser-Diodes,” Applied Physics Letters, Vol. 59, Iss. 11, pp. 1272-1274, 1991
[19] T. D. Moustakas, T. Lei and R. J. Molnar, ”Growth of GaN by ECR-Assisted MBE,” Physica B, Vol. 185, Iss. 1-4, pp. 36-49, 1993
[20] M.E. Lin, B. Sverdlov, and H. Morkoc, “Growth and Characterization of GaN on C-Plane (0001) Sapphire Substrates by Plasma-Enhanced Molecular-Beam Epitaxy,“ Journal of Applied Physics, Vol. 74, Iss. 8, pp. 5038-5041, 1993
[21] H. G. Grimmeiss, and B. Monemar, “Low-Temperature Luminescence of GaN,” Journal of Applied Physics, Vol. 41, pp. 4054-4058, 1970
[22] K. Naniwae, S. Itoh, H. Amano, K. Itoh, K. Hiramatsu, and I. Akasaki, “Growth of Single-Crystal GaN Substrate Using Hydride Vapor-Phase Epitaxy,” Journal of Crystal Growth, Vol. 99, Iss. 1-4, pp. 381-384, 1990
[23] H. Amano, I. Akasaki, and K. Hiramatsu, “Heteroepitaxial Growth and the Effect of Strain on the Luminescent Properties of GaN Films on (1120) and (0001) Sapphire Substrates,” Japanese Journal of Applied Physics Part 2-Letters, Vol. 27, Iss. 8, pp. 1384-1386, 1988
[24] I. Akasaki, H. Amano, Y. Koide, K. Hiramatsu and N. Sawaki, “Effects of AlN Buffer Layer on Crystallographic Structure and on Electrical and Optical-Properties of GaN and Ga1-XAlxN(0-Less-Than-X-Less-Than-or-Equal-to-0.4) Films Grown on Sapphire Substrate by MOVPE,” Journal of Crystal Growth, Vol. 98, Iss. 1-2, pp. 209-219, 1989
[25] H. Amano, I. Akasaki, N. Sawaki, N. Koide, N. Koide, and K. Hiramatsu, “Effects of the Buffer Layer in Metalorganic Vapor-Phase Epitaxy of GaN on Sapphire Substrate,” Thin Solid Films, Vol. 163, Iss. SEP, pp. 415-420, 1988
[26] H. Amano, M. Kito, K.Hiramatsu, and I. Akasaki, “P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron-Beam Irradiation,” Japanese Journal of Applied Physics Part 2-Letters, Vol. 28, Iss. 12, pp. 2112-2114, 1989
[27] I. Akasaki, H.Amano, M. Kito, K.Hiramatsu, “Photoluminescence of Mg-Doped P-Type GaN and Electroluminescence of GaN P-N-Junction Led,” Journal of Luminescence, Vol. 48-9, Iss. JAN-, pp. 666-670, 1991
[28] S. Nakamura, Y. Harada, and M. Senoh, “Novel Metalorganic Chemical Vapor-Deposition System for GaN Growth,” Applied Physics Letters, Vol. 58, Iss. 18, pp. 2021-2023, 1991
[29] S. Nakamura, Takashi Mukai, M. Senoh, and N. Iwasa,” Thermal Annealing Effects on P-Type Mg-Doped GaN Films,” Japanese Journal of Applied Physics Part 2-Letters, Vol. 31, Iss. 2B, pp. 139-142, 1992
[30] M. A. Khan, Q. Chen, R. A. Skogman, and J. N. Kuznia, “Violet-Blue GaN Homojunction Light-Emitting-Diodes with Rapid Thermal Annealed P-Type Layers,” Applied Physics Letters, Vol. 66, Iss. 16, pp. 2046-2047, 1995
[31] W. Gotz, N. M. Johnson, J. Walker, D. P. Bour, and R.A. Street, “Activation of Acceptors in Mg-Doped GaN Grown by Metalorganic Chemical-Vapor-Deposition,” Applied Physics Letters, Vol. 68, Iss. 5, pp. 667-669, 1996
[32] S. Nakamura, M. Senoh, and T. Mukai, “High-Power InGaN/GaN Double-Heterostructure Violet Light-Emitting-Diodes,” Applied Physics Letters, Vol. 62, Iss. 19, pp. 2390-2392, 1993
[33] S. Nakamura, T. Mukai, and M. Senoh, ”Candela-Class High-Brightness InGaN/AlGaN Double-Heterostructure Blue-Light-Emitting Diodes,” Applied Physics Letters, Vol. 64, Iss. 13, pp. 1687-1689, 1994
[34] C.W. Tang, S.A. Vanslyke, “Organic electroluminescent diodes” Applied Physics Letters, Vol. 51, Iss. 12, pp 913-915, 1987
[35] Z. Shen, P.E. Burrows, V. Bulovic, S.R. Forrest, M.E. Thompson, “Three-Color, Tunable, Organic Light-Emitting Devices” Science, Vol. 276, Iss. 27, pp. 2009-2011, 1997
[36] M. Yoshida, A. Fujii, Y.Ohmori, K.Y oshino, “Polarity-Dependent Multicolor Organic Electroluminescent Device” Japanese Journal
of Applied Physics Part 2-Letters, Vol. 35, Iss. 10, pp. 397-400, 1996
[37] P.E. Burrows, G.Gu, V. Bulovic, Z.Shen, S.R.Forr est, M.E. Thompson, “Achieving full-color organic light-emitting devices for lightweight, flat-panel displays” IEEE TRANSACTIONS ON ELECTRON DEVICES, Vol. 44, Iss. 8, pp. 1188-1203, 1997
[38] J.M.Shi, C.W.Tang, “Doped organic electroluminescent devices with improved stability” Applied Physics Letters, Vol. 70, Iss. 13, pp. 1665-1667, 1997
[39] Vi-E. Choohe, S. Shi, J. Curless, C.L. Shieh, H.C. Lee, F. So, J.
Shen, J.Y ang, “Organic light-emitting diodes with a bipolar transport layer” Applied Physics Letters, Vol. 75, Iss. 2, pp. 172-174, 1999
[40] Y.Sakakibara, S.Okutsu, T. Enokida, T. Tani, “Red organic electroluminescence devices with a reduced porphyrin compound, tetraphenylchlorin” Applied Physics Letters, Vol. 74, Iss. 18, pp. 2587-2589, 1999
[41] Y. Hamada, H.Kanno, T.T sujioka, H. Takahashi, T. Usuki, “Red organic light-emitting diodes using an emitting assist dopant”
Applied Physics Letters, Vol. 74, Iss. 18, pp. 2587-2589, 1999
[42] P.E. Burrows, S.R.Forr est, “Operating lifetime of phosphorescent organic light emitting devices” Applied Physics Letters, Vol. 76, Iss. 18, pp. 2493-2495, 2000
[43] Jiang Xue-Yin, Zhang Zhi-Lin, Zheng Xin-You, Wu You-Zhi, Xu Shao-Hong “A blue organic emitting diode from anthracene derivative” Thin Solid Films, Vol. 401, Iss. 1, pp. 251-254, 2001
[44] Z.Q. Gao, C.S. Lee, I. Bello, S.T. Lee, S.K. Wu, Z.L. Yan, X.H. Zhang “Blue organic electroluminescence of, 3, 5-triaryl-2- pyrazoline” Synthetic Metals, Vol. 105, Iss. 1, pp. 141-144, 1999
[45] D. K. Gaskill, A. E. Wickenden, K. Doverspike, B. Tadayon and L. B. Rowland, “The Effect of Organometallic Vapor-Phase Epitaxial-Growth Conditions on Wurtzite GaN Electron-Transport Properties,“ Journal of Electronic Materials, Vol. 24, Iss. 11, pp. 1525-1530, 1995
[46] K. G. Fertitta, A. L. Holmes, F. J. Ciuba, R. D. Dupuis, and F. A. Ponce, “High-Quality GaN Heteroepitaxial Films Grown by Metalorganic Chemical-Vapor-Deposition, “Journal of Electronic Materials, Vol. 24, Iss. 4, pp. 257-261, 1995
[47] B. P. Keller S. Keller, D. Kapolnek, W. N. Jiang, Y. F. Wu, H. Masui, X. Wu, B. Heying, J. S. Speck, U. K. Mishra, and S. P. Denbaars, “Metalorganic Chemical-Vapor-Deposition Growth of High Optical-Quality and High-Mobility GaN, “Journal of Electronic Materials, Vol. 24, Iss. 11, pp. 1707-1709,1995
[48] S. D. Hersee, J. Ramer, K. Zheng, C. Kranenberg, K. Malloy, M. Banas, and M. Goorsky, “The Role of the Low-Temperature Buffer Layer and Layer Thickness in the Optimization of OMVPE Growth of GaN on Sapphire,” Journal of Electronic Materials, Vol. 24, Iss. 11, pp. 1519-1523, 1995
[49] X. H. Wu, D. Kapolnek, E. J. Tarsa, B. Heying, B. P. Keller, U. K. Mishra, S. P. Denbaars, and J. S. Speck, “Nucleation Layer Evolution in Metal-Organic Chemical-Vapor-Deposition Grown GaN,” Applied Physics Letters, Vol. 68, Iss. 10, pp. 1371-1373, 1996
[50] R. Niebuhr, K. Bachem, K. Dombrowski, M. Maier, W. Pletschen and U. Kaufmann, “Basic Studies of Gallium Nitride Growth on Sapphire by Metalorganic Chemical-Vapor-Deposition and Optical-Properties of Deposited Layers, “Journal of Electronic Materials, Vol. 24, Iss. 11, pp. 1531-1534, 1995
[51] G. C. Chi, C. H. Kuo, J. K. Sheu, C. J. Pan, “The doping process of p-type GaN films” Materials Science and Engineering:B, Vol. 75, Iss. 2-3, pp. 210-213, 2000
[52] R. J. Molnar, R. Singh, and T. D. Moustakas, “Blue-violet light emitting gallium nitride p-n junctions grown by electron cyclotron resonance-assisted molecular beam epitaxy” Applied Physics Letters, Vol. 66, Iss. 3, pp. 268-270, 1995
[53] S. Nakamura, T. Mukai, and M. Senoh, ”Candela-Class High-Brightness InGaN/AlGaN Double-Heterostructure Blue-Light-Emitting Diodes,” Applied Physics Letters, Vol. 64, Iss. 13, pp. 1687-1689, 1994
[54] H. Jeon, V. Kozlov, P. Kellkar, A. V. Nurmikko, C. C. Chu, D. C. Grillo, J. Han, G. C. Hua, and R. L. Gunshor, “Room-Temperature Optically Pumped Blue-Green Vertical-Cavity Surface-Emitting Laser,” Applied Physics Letters, Vol. 67, Iss. 12, pp. 1668-1670, 1995
[55] T. Ogino and M. Aoki, “Mechanism of Yellow Luminescence in GaN,” Japanese Journal of Applied Physics 1980, Vol. 19, Iss. 12, pp. 2395-2405
[56] A. E. Wickenden, D. K. Wickenden and T. J. Kistenmacher, “The Effect of Thermal Annealing on GaN Nucleation Layers Deposited on (0001) Sapphire by Metalorganic Chemical-Vapor-Deposition,“ Journal of Applied Physics, Vol. 75, Iss. 10, pp. 5367-5371, 1994
[57] M. A. Khan, J. M. Vanhove, J. N. Kuznia, and D. T. Olson, “High Electron-Mobility GaN/AlxGa1-XN Heterostructures Grown by Low-Pressure Metalorganic Chemical Vapor-Deposition,“ Applied Physics Letters, Vol. 58, Iss. 21, pp. 2408-2410, 1991
[58] S. Fischer, C. Wetzel, E. E. Haller and, B. K. Meyer “On p-type doping in GaN—acceptor binding energies” Applied Physics Letters, Vol. 67, Iss. 9, pp. 1298-1300, 1995
[59] E. R. Glaser, T. A. Kennedy, K. Doverspike, L. B. Rowland, D. K. Gaskill, J. A. Freitas, M. A. Kahn, D. T. Olson, J. N. Kuznia, and D. K. Wickenden, “Optically Detected Magnetic-Resonance of GaN Films Grown by Organometallic Chemical-Vapor-Deposition, “Physical Review B-Condensed Matter, Vol. 51, Iss. 19, pp. 13326-13336, 1995
[60] Amano-H Akasaki-I Sawaki-N Toyoda-Y,” Metalorganic Vapor-Phase Epitaxial-Growth of a High-Quality GaN Film Using an AlN Buffer Layer,” Applied Physics Letters 1986, Vol. 48, Iss. 5, pp. 353-355
[61] Kenji Uchida, Akiyoshi Watanabe, and Fumiko Yano, “Nature of nitridated layers formed on the sapphire surface and their effect on the growth of GaN,” International Symposium on Blue Laser and Light Emitting Diodes, Chiba Univ., Japan, March 5-7,1996
[62] Heinlein C., Grepstad J., Riechert H. and Averbeck R. “Plasma
preconditioning of sapphire substrate for GaN epitaxy” Materials Science and Engineering: B, Vol. 43, Iss. 1, pp. 253-257, 1997
[63] I. Bertoti,”Characterization of nitride coatings by XPS” Surface and Coatings Technology, Vol.151-152, pp. 194-203, 2002
[64] T. Suski, P. Berlin, H. Teisseyre, M. Leszcyńsky, I. Grzegory, J. Jun, M. Boćkowski, S. Porowski, and T. D. Moustakas, “Mechanism of Yellow Luminescence in GaN, “Applied Physics Letters, Vol. 67, Iss. 15, pp. 2188-2190, 1995
[65] X. Zhang, P. Kung, and M. Razeghi, in Gallium Nitride and Related Materials, edited by R. D. Dupuis, F. A. Ponce, J. A. Edmond, and S. Nakamura (MRS Symposia Proceedings, World Scientific, Singapore, 1995), Vol. 395
[66] W. Götz, N Johnson, J. Walker, D. P. Bour. H. Amano, and I. Akasaki, Proceedings of the 6th Int. Conf. on SiC and Related Materials (in press); private communication
[67] F. A. Ponce, D. P. Bour, W. Götz, N. M. Johnson. H. I. Helava, I. Grzegory, J. Jun, and S. Porowski, “Homoepitaxy of GaN on Polished Bulk Single-Crystals by Metalorganic Chemical-Vapor-Deposition, “Applied Physics Letters, Vol. 68, Iss. 7, pp. 917-919, 1996
[68] R. Niebuhr, K. Bachem, K. Dombrowski, M. Maier, W. Pletschen and U. Kaufmann, “Basic Studies of Gallium Nitride Growth on Sapphire by Metalorganic Chemical-Vapor-Deposition and Optical-Properties of Deposited Layers, “Journal of Electronic Materials, Vol. 24, Iss. 11, pp. 1531-1534, 1995
[69] P.Bobuslawaki, and J.Bernholc, “ Doping properties of C, Si, and Ge impurities in GaN and AlN”, Physical Review B, Vol. 56, Num. 15, pp. 9496-9505, 1997
[70] J. Neugebauer and C. G. Van de Walle, “Gallium vacancies and the yellow luminescence in GaN” Applied Physics Letters, Vol. 69, Iss. 4, pp. 503-505, 1996