Dependence of the structural and optical properties on the Cd mol fractionin 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 degener ate valence band splitting into the heavy hole and the light hole bands was observed as the Cd mol fraction increased, which originated from the incre ase of the strain magnitude due to the increase of the lattice mismatch bet ween the CdxZn1-xTe epilayer and the GaAs substrate. Raman spectra showed t hat 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 an d optical properties for improving optoelectronic devices qualities operati ng in the blue-green spectral region. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.