Photoluminescence (PL) properties of undoped InAs autoepitaxial layers are studied at various temperatures (9-120 K) and excitation power density (0.2-12.5 W/cm2). The studied structures have been grown on highly doped n++-InAs substrates by chloride-hydride vapour phase epitaxy method. PL spectra measurements were carried out with an FTIR spectrometer. The samples exhibit several luminescence peaks in the 2.9-3.3 μm range, which are attributed to free exciton transitions, deep donor bound excitons, and donor-acceptor pairs. A correlation is revealed between the PL intensity, and the background doping level of InAs epilayers – as supported by the free carrier concentration and mobility measurements, as well as SIMS data. A decrease of donor-bound exciton PL peak is observed for InAs sulfidized by Na2S.
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