Structure of CdTe/ZnTe superlattices

Abstract
The structure of CdTe/ZnTe superlattices has been analyzed through θ/2θ x‐ray diffraction, photoluminescence, and i n s i t u reflection high‐energy electron diffraction(RHEED) measurements. Samples are found to break away from Cd x Zn1−x Te buffer layers as a consequence of the 6% lattice mismatch in this system. However, defect densities in these superlattices are seen to drop dramatically away from the buffer layerinterface, accounting for the intense photoluminescence and high‐average strain fields seen in each of our samples. Observed variations in residual strains suggest that growth conditions play a role in forming misfit defects. This could explain discrepancies with calculated values of critical thickness based on models which neglect growth conditions. Photoluminescencespectra reveal that layer‐to‐layer growth proceeded with single monolayer uniformity, suggesting highly reproducible growth. Our results give hope for relatively defect‐free Cd x Zn1−x Te/Cd y Zn1−y Te superlattices with the potential for applications to optoelectronics offered by intense visible light emitters.