A study was made of the low-temperature photoluminescence of unintentionally doped and Si-doped bulk material grown, by low-pressure metalorganic vapour-phase epitaxy, from triethylgallium, trimethylantimony and silane. Background doping with Si, in nominally undoped layers, was shown to be caused by the trimethylantimony precursor. Intentional Si-doping, using silane, resulted in p-doping, a reduction in material compensation, a substantial decrease in the native acceptor concentration and a marked gain in the integral photoluminescence intensity as compared with unintentionally-doped samples. The results suggested that the Si atoms were incorporated mainly in the anionic sub-lattice. The Si-related photoluminescence line with a maximum at 0.8eV, observed in the photoluminescence spectra of both types of sample at liquid-He temperatures, was identified as being a transition of a free electron to a neutral acceptor, SiSb; with an activation energy of about 0.009eV. The photoluminescence spectra of layers with acceptor concentrations approaching 1017/cm3, and particularly a blue-shift of the 0.80eV peak with increasing temperature, could be understood by taking account of the impact of large-scale fluctuations in the charged impurity concentration.

Origin of the Photoluminescence Line at 0.8eV in Undoped and Si-Doped GaSb Grown by MOVPE. C.Agert, P.S.Gladkov, A.W.Bett: Semiconductor Science and Technology, 2002, 17[1], 39-46