[1] Mohammad S N, Salvador A A and Morkoc H 1995 IEEE
Proc. 83 1306

[2] Masayoshi K, Naoki S, Hisaki K and Yuji T 2002 IEEE
J. Sel. Top. Quantum Electron. 8 271

[3] Armstrong A, Arehart A R, Moran B, DenBaars S P, Mishra U
K, Speck J S and Ringel S A 2003 International Symposium on
Compound Semiconductors: Post-Conference Proceedings Chap (San Diego, CA: 25--27 August 2003) chap 8 pp 25
42

[4] Zhao D G, Jiang D S, Zhu J J et al 2008 Chin. Phys.
Lett. 25 4143

[5] Chen J R, Chen W J, Wang Y Q et al 2007 Chin. Phys.
Lett. 24 2112

[6] Lee H Y, Huang X Y and Lee C T 2008 J. Electrochem.
Soc. 155 H707

[7] Kelly M K, Ambacher O, Dahlheimer B et al 1996 Appl.
Phys. Lett. 69 1749

[8] Horng R H, Huang S H, Hsieh C Y, Zheng X H and Wu D S 2008
IEEE J. Quantum Electron. 44 1116

[9] Huang S Y, Horng R H, Liu P L, Wu J Y, Wu H W and Wuu D S
2008 IEEE Photon. Technol. Lett. 20 797

[10] Wang T, Guo X, Fang Y, Liu B and Shen G D 2007 J.
Funct. Mater. 1 88 (in Chinese)

[11] Chu C F, Lai F I, Chu J T et al 2004 J. Appl. Phys.
95 3916

[12] Wang T, Fang Y, Guo X, Shen G D and Cui Z Z 2007
Thin Solid Films 515 3854