Post-annealing effect upon phosphorus-doped ZnTe homoepitaxial layers grown by MOVPE

The effect of post-annealing treatment upon the photoluminescence (PL) spectra of phosphorus-doped ZnTe homoepitaxial layers grown by metalorganic vapour phase epitaxy using tris-dimethylaminophosphorus (TDMAP) has been investigated. PL properties at 4 K of the layers are dramatically improved by the post-annealing in nitrogen flow, i.e. donor-acceptor pair emission vanishes and instead free-to-bound transition emission (FB) and broadened acceptor-related excitonic emission (I-a) appear. PL intensity at room temperature is enhanced remarkably by the treatment. While the post-annealing treatment in hydrogen flow also gives an increase in PL intensity at room temperature of the layer, PL spectrum at 4 K is almost unchanged. The intensity ratio of FB to broadened I-a for the layer after post-annealing treatment in nitrogen flow increases and the broadened I-a shifts towards longer wavelength side with increasing TDMAP transport rate. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.