Reference

1.M.Nakamura, J. of Crystal Growth 209(2000)232-236

2.Makota Kitabatake,Thin Solid Films,369(2000)257-264

3.Makoto Itoh, Physical Review B, Vol.62 Number 11. Sep15, 2000-I,Page 7219

4.Z.M.Wang, Physical Review B, Vol.61, Number 4, Jan 15 2000-II,Page R2440

5.M.Wassermeier, Apllied Surface Science, 123/124(1998) 181-186