Growth and characterization of low-temperature grown GaN with high Fe doping

We succeeded in growing highly Fe-doped GaN films by solid-source molecular beam epitaxy using an electron-cyclotron-resonance microwave nitrogen plas ma. The substrate temperature was in the range of 380-520 degreesC. The sam ples were analyzed by x-ray diffraction and transmission electron microscop y, and showed hexagonal (wurtzite) or cubic (zincblende) structure or a mix ture of both phases. The Fe concentration was on the order of 10(19) cm(-3) and extended x-ray absorption fine structure data show that the Fe is subs tituting the Ga in GaN. The magnetization measurements as a function of tem perature reveal ferromagnetic properties below 100 K for the sample grown a t the lowest temperature. (C) 2000 American Institute of Physics. [S0003- 6 951(01)00601-5].