Dependence of the structural and optical properties on the Cd mol fraction in CdxZn1−xTe/GaAs heterostructures

Lattice-mismatched CdxZn1−xTe epilayers with various Cd mol fractions were grown on GaAs (100) substrates by molecular beam epitaxy. X-ray diffraction patterns and Auger depth profiles showed that the grown layers were CdxZn1−xTe epitaxial films. The photoluminescence spectra showed that the degenerate valence band splitting into the heavy hole and the light hole bands was observed as the Cd mol fraction increased, which originated from the increase of the strain magnitude due to the increase of the lattice mismatch between the CdxZn1−xTe epilayer and the GaAs substrate. Raman spectra showed that the frequency of the longitudinal-optical mode decreased as the Cd mol fraction increased, which was caused by the decrease of the mode oscillator strength. These results provide important information on the structural and optical properties for improving optoelectronic devices qualities operating in the blue-green spectral region.