4Brunner F, Knauer A, Schenk T, et al. Quantitative analysis of in situ wafer bowing measurements for III- nitride growth on sapphire [J]. Journal of Crystal Growth, 2008, 310(10):2432-2438.
5Edward D. Hanbook of optical constants of solids [M]. Boston:Academic Press, 1985.
6Yu G, Wang G, Ishikawa H, et al. Optical proper- ties of wurzite structure GaN on sapphire around fun-damental absorption edge(0.78-4.77eV) by spec- troscopic ellipsometry and the optical transmission method[J]. Appl. Letter. , 1997, 70 (24): 3209- 3211.