Photoluminescence in CdTe grown on GaAs by metalorganic chemical vapor deposition

Abstract

Epitaxial layers of CdTe grown on (100) GaAs substrates by metalorganic chemical vapor deposition at temperatures between 320 and 410 °C were investigated by photoluminescent measurements at 14 K. The sharp bound exciton-related peak at 1.594 eV, the band-edge emission located near 1.557 eV, and the weak defect-related extrinsic band at 1.476 eV, with their well-resolved longitudinal optical phonon replicas were the observed major photoluminescence peaks. The variations of these peak intensities are a strong function of the epilayer growth temperatures. The intensity ratio of the defect-related emission peak to the bound exciton peak decreases to less than 1/10 as the growth temperature is adjusted within 360 and 390 °C. For the CdTe epitaxial layer grown at 375 °C, the peak related to defects is completely eliminated.