Photoluminescence in CdTe grown on GaAs by metalorganic chemical vapor deposition

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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.