Structural and optical characterization of epitaxial layers of CdTe/PbTe grown on BaF2 (111) substrates

CdTe and CdTe/PbTe layers were grown on BaF2 (111) substrates by molecular beam epitaxy technique employing PbTe, CdTe, and Te-2 effusion cells. The layers are monocrystalline with (111) crystal orientation and exhibit x-ray rocking curve FWHM parameter of 100-300 arcsec for PbTe and Me. The well defined streaky RHEED diffraction pattern was observed during the process of growth of both layers indicating a two-dimensional mode of growth. For the optical characterization of CdTe layers, the photoluminescence spectra were studied at T = 4.2 K in 750-870 nm (1.40-1.65 eV) spectral range using pulsed excitation at 2.35 eV by Nd:YAG laser. In CdTe/BaF2 layers, the dominant photoluminescence peak is observed at 785 nm and corresponds to the radiative recombination of excitons bound to neutral acceptors. In CdTe/PbTe/BaF2 heterostructures with thick PbTe buffer, no photoluminescence is observed in the spectral range studied. (c) 2005 WILEY-VCH Verlag GmbH C Co. KGaA, Weinheim.