Deep-level transient spectroscopy and cathodoluminescence of CdxZn1-xTe/ZnTe QW structures grown on GaAs(100) by MBE

MBE-grown ZnTe/CdZnTe/ZnTe strained single quantum well (SQW) and multiple quantum well (MQW) structures with non-doping layers were investigated by cathodoluminescence (CL) and deep-level transient spectroscopy (DLTS). The DLTS method with electrical current relaxation was used because the as-grown structures were compensated. The activation energies of 0.21 and 0.58 eV for deep levels in ZnTe buffer layers grown on GaAs were determined by the DLTS spectra. Besides, an additional DLTS peak (E-t = 34-133 meV) that depends on the quantum well parameters and correlates with the QW emission line position in the CL spectra was observed. This peak is interpreted as an emission of electrons from a ground level of dimensional quantization in a conduction band. Obtained DLTS and CL results were used for an estimation of a conduction-band offset parameter Q(c). (C) 2000 Elsevier Science B.V. All rights reserved.