First-principles calculation and X-ray absorption fine structure analysis of Fe doping mechanism for semi-insulating GaN growth on GaAs substrates

摘要

In order to fabricate an Fe-doped semi-insulating (SI) GaN substrate by hydride vapor phase epitaxy (HVPE) using (111)A GaAs as a starting substrate, the Fe doping mechanism was investigated by two approaches: first-principles calculation and X-ray absorption fine structure (XAFS) measurements, First-principles study clarified that Fe and As atoms are substituting for the Ga and N atoms in the wurtzite GaN lattice, respectively. In addition, incorporation of Fe in GaN was found to be hindered by adjacent As in the N site. XAFS analysis performed for an Fe-doped SI GaN substrate, obtained by protecting backside of the GaAs substrate, showed that the Fe atoms are substituting for the Ga site in GaN. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.