Theoretical Study on the Optical and Electrical Properties of Al_xGa_1-xN Crystals

Xuewen Wang, Yuzhou Jing, Xinkang Zhu, Chan Liu, Jiangni Yun, Zhiyong Zhang

School of Information Science and Technology, Northwest University, Xi’an, China.

DOI: 10.4236/jmp.2013.43A063                

Abstract

By making use of the density functional theory (DFT) of the first principles and generalized gradient approximation method, the electronic structures and properties of ideal GaN and Al_xGa_1-xN crystals (x = 0.25, 0.5, 0.75) have been calculated and analyzed, and the influence of the doping quantity of x on the characteristics of Al_xGa_1-xN has been studied. The calculation results show that optical band gap of Al_xGa_1-xN crystal is widened that the E_g of Al_xGa_1-xN can be adjusted by the x, and the absorption spectrum shifts to high-energy direction with the increase of the x, and then the Fermi energy moves to the top of valence band slightly which leads to that conductivity weakened after mixed with the Al. At the same time, the variation trends of complex dielectric function, absorption spectrum and transitivity have been made clear, and the results show that Al_xGa_1-xN compounds can achieve the theoretical design of photoelectric performance. In a word, Al_xGa_1-xN crystals are potential semiconductors with very remarkable photoelectric properties, which can be applied in the development of the diversified GaN devices.

Keywords

DFT; Al_xGa_1-xN Crystal; Electronic Structure; Properties

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	I. Yonenaga, “Thermo-Mechanical Stability of Wide-Band-Gap Semiconductors: High Temperature Hardness of SiC, AlN, GaN, ZnO and ZnSe,” Physica B: Condensed Matter, Vol. 308-310, 2001, pp. 1150-1152. doi:10.1016/S0921-4526(01)00922-X
[2]	A. Goswami, R. J. Trew and G. L. Bilbro, “Physics Based Modeling of Gate Leakage Current Due to Traps in Al-GaN/GaN HFETs,” Solid-State Electronics, Vol. 80, 2013, pp. 23-27. doi:10.1016/j.sse.2012.10.005
[3]	F. X. Wang, H. Lu, X. Q. Xiu, D. J. Chen, P. Han, R. Zhang and Y. D. Zheng, “Leakage Current and Sub-Bandgap Photo-Response of Oxygen-Plasma Treated GaN Schottky Barrier Diodes,” Applied Surface Science, Vol. 257, 2011, pp. 3948-3951.
[4]	S. J. Chang, T. K. Ko, J. K. Sheu, S. C. Shei, W. C. Lai, Y. Z. Chiou, Y. C. Lin, C. S. Chang, W. S. Chen and C. F. Shen, “AlGaN Ultraviolet Metal-Semiconductor-Metal Photodetectors Grown on Si Substrates,” Sensors and Actuators A: Physical, Vol. 135, No. 2, 2007, pp. 502-506. doi:10.1016/j.sna.2006.09.017
[5]	D. Fu, R. Zhang, B. G. Wang, B. Liu, Z. L. Xie, X. Q. Xiu, H. Lu, Y. D. Zheng and G. Edwards. Ultraviolet Emission Efficiencies of AlxGa1-xN Films Pseudomorphically Grown on AlyGa1-yN Template (x < y) with Various Al-Content Combinations,” Thin Solid Films, Vol. 519, No. 22, 2011, pp. 8013-8017.
[6]	S. Li, C. Y. Ouyang, “First Principles Study of Wurtzite and Zinc Blende GaN: A Comparison of the Electronic and Optical Properties,” Physics Letters A, Vol. 336, No. 2-3, 2005, pp. 145-151.
[7]	Y.-J. Du, B.-K. Chang, J.-J. Zhang, B. Li and X.-H. Wang, “First-Principles Study of the Electronic Structure and Optical Properties of GaN (0001) Surface,” Acta Physico-Chimica Sinica, Vol. 61, No. 6, 2012, Article ID: 067101.
[8]	N. Safta, H. Mejri, H. Belmabrouk and M. A. Za?di, “Effects of High Doping on the Bandgap Bowing for AlxGa1-xN,” Microelectronics Journal, Vol. 37, No. 11, 2006, pp. 1289-1292. doi:10.1016/j.mejo.2006.07.010
[9]	O. Arbouche, B. Belgoumène, B. Soudini and M. Driz, “First Principles Study of the Relative Stability and the Electronic Properties of GaN,” Computational Materials Science, Vol. 47, No. 2, 2009, pp. 432-438.
[10]	Y. J. Du, B. K. Chang, X. Q. Fu, X. H. Wang and M. S. Wang, “Electronic Structure and Optical Properties of Zinc-Blende GaN, Optik,” International Journal for Light and Electron Optics, Vol. 123, No. 24, 2012, pp. 2208-2212. doi:10.1016/j.ijleo.2011.10.017
[11]	X. C. Li, “Principles Calculations of the Electronic Structures and Optical Properties of Oxygen Passivated 4H-SiC Nanostructures [D],” Nankai University, Tianjin, 2010.