[2] [2] Kou L, Hall D C, Wu H. Appl. Phys. Lett., 1998, 72: 3411.

[3] [3] Hehlen M P, Cockroft N J, Gosnell T R. Phys. Rev., B 1997, 56: 9302.

[4] [4] Strohhofer C, Kik P G, Polman A J. Appl. Phys., 2000, 88: 4486.

[5] [5] Vetrone F, Boyer J C, Capobianco J A, et al. J. Phys. Chem. B, 2003, 107: 1107.

[6] [6] Biljan T, Gajovic A, Meic Z, et al. J. Alloys Compd., 2007, 431: 217.

[7] [7] Vega-Duran J T, Barbosa-Garcia O, Diaz-Torres L A, et al. Appl. Phys. Lett., 2000, 76: 2032.

[8] [8] Sardar D K, Gruber J B, Hutchinson J A, et al. J. Appl. Phys., 2003, 93: 2041.

[9] [9] Gruber J B, Sardar D K, Zandi B, et al. J. Appl. Phys., 2003, 94: 4835.

[10] [10] Zhou J, Moshary F, Gross B M, et al. J. Appl. Phys., 2004, 96: 237.

[11] [11] Lei Y Q, Song H W, Yang L M, et al. J. Chem. Phys., 2005, 123: 174710.

[12] [12] Antic-Fidancev E, Holsa J, Lastusaari M. J. Phys. Condens. Matter., 2003, 15: 863.

[13] [13] Song H W, Chen B J, Peng H S, et al. Appl. Phys. Lett., 2002, 81: 1776.

[14] [14] Jia M L, Zhang J H, Lu S Z, et al. Chem. Phys. Lett., 2004, 384: 193.

[15] [15] Trojan-Piegza J, Zych E. J. Alloys Compd., 2004, 380: 118.

[16] [16] Pelle F, Goldner P. Phys. Rev. B, 1993, 48: 9995.

[17] [17] Takahashi M, Lzuki M, Kanno R, et al. J. Appl. Phys., 1998, 83: 3920.

[18] [18] Zhang H X, Kam C H, Zhou Y, et al. Appl. Phys. Lett., 2000, 77: 609.

[19] [19] De la Rosa-Cruz E, Diaz-Torres L A, Rodriguez-Rojas R A, et al. Appl. Phys. Lett., 2003, 83: 4903.