Electron and Hole Capture Cross-Sections of Fe Acceptors in GaN:Fe Epitaxially Grown on Sapphire

Abstract

Carrier trapping of Fe3+/Fe2+ deep acceptors in epitaxially grown GaN:Fe on sapphire was studied by time-resolved photoluminescence. For the investigated Fe doping levels on the order of 1018 cm−3, the luminescence decay times are strongly dependent on the Fe concentration, indicating that Fe centers act as predominant nonradiative recombination channels. Linear dependence of the decay time on the iron concentration allows estimation of the electron capture cross-section for the Fe3+ ions, which is equal to 1.9 × 10−15 cm2. The upper bound for the cross-section of the hole capture of Fe2+ was evaluated as 1 × 10−15 cm2.