[1] Yang T, Tatebayashi J, Tsukamoto S, Nishioka M and Arakawa Y 2004
Appl. Phys. Lett. 84 2817

[2] Pan D, Towe E and Kennerly S 2000 Appl. Phys. Lett. 76
3301

[3] Tatebayashi J, Hatori N, Ishida M, Ebe H, Sugawara M, Arakawa Y,
Sudo H and Kuramata A 2005 Appl. Phys. Lett. 86 053107

[4] Chen Z, Baklenov O, Kim E, Mukhametzhanov I, Tie J, Madhukar A, Ye
Z and Campbell J C 2001 J. Appl. Phys. 89 4558

[5] Madhukar A, Ramachandran T R, Konkar A, Mukhametzhanov I, Yu W and
Chen P 1998 Appl. Surf. Sci. 123/124 266

[6] Kaizu T, Takahasi M, Yamaguchi K and Mizuki J 2007 J. Crystal
Growth 301-302 248

[7] Riel B J, Hinzer K, Moisa S, Fraser J, Finnie P, Piercy P, Fafard S
and Wasilewski Z R 2002 J. Crystal Growth 236 145

[8] Nishi K, Saito H, Sugou S and Lee J S 1999 Appl. Phys.
Lett. 74 1111

[9] Lin C H, Pai W W, Chang F Y and Lin H H 2007 Appl. Phys.
Lett. 90 063102

[10] Amano T, Sugaya T, Yamauchi S and Komori K 2006 J. Crystal
Growth 295 162

[11] Amano T, Yamauchi S, Sugaya T and Komori K 2006 Appl. Phys.
Lett. 88 261110

[12] Ripalda J M, Alonso-Alvarez D, Alen B, Taboada A G, Garcia J M,
Gonzalez Y and Gonzalez L 2007 Appl. Phys. Lett. 91 012111

[13] Guimard D, Nishioka M, Tsukamoto S and Arakawa Y 2007 J.
Crystal Growth 298 548

[14] Matsuura T, Miyamoto T, Ohta M, Matsui Y, Furuhata T and Koyama F
2005 J. Crystal Growth 278 51

[15] Yamaguchi K and Kanto T 2005 J. Crystal Growth 275
e2269

[16] Matsuura T, Miyamoto T, Kageyamay T, Ohta M, Matsui Y, Furuhata T
and Koyama F 2006 Jpn. J. Appl. Phys. 43 L605

[17] Shimizu H and Saravanan S 2006 Appl. Phys. Lett. 88
041119

[18] Guimard D, Tsukamoto S, Nishilka M and Arakawa Y 2006 Appl.
Phys. Lett. 89 083116

[19] Costantini G, Rastelli A, Manzano C, Acosta-Diaz P, Songmuang R,
Katsaros G, Schmidt O G and Kern K 2006 Phys. Rev. Lett. 96 226106

[20] Garc\'\i a J M, Medeiros-Ribeiro G, Schmidt K, Ngo T, Feng J
L, Lorke A, Kotthaus J and Petroff P M 1997 Appl. Phys. Lett.
71 2014

[21] Joyce P B, Krzyzewski T J, Bell G R, Jones T S, Malik S, Childs D
and Murray R 2001 J. Crystal Growth 227-228 1000

[22] Convertino A, Cerri L, Leo G and Viticoli S 2004 J. Crystal
Growth 261 458

[23] Varshni Y P 1967 Physica 34 149

[24] Mi Z and Bhattacharyaa P 2005 J. Appl. Phys. 98 023510