Non-invasive and non-destructive characterization of MBE-grown CdZnTe/CdTe superlattice-based dislocation filtering layers

We report on the structural and optical properties of heteroepitaxial II-VI CdTe (211)B buffer layers with strained CdZnTe/CdTe superlattice layers, investigated by employing non-destructive methods including high-resolution x-ray diffraction, cathodoluminescence, and photoluminescence spectroscopy. X-ray diffraction reciprocal space mapping measurements revealed that the superlattice layers are coherently strained, leading to a spread in x-ray double-crystal rocking curve full-width at half-maximum values but better in-plane lattice-matching with HgCdTe. Both cross-sectional cathodoluminescence and photoluminescence measurements confirm the coherent growth of superlattice layers and their dislocation filtering effects. Both these techniques in CdTe layers are found to be well correlated with the dislocation density as determined by etch pit density measurements. The results indicate the potential of these non-destructive methods to be further developed into general-purpose techniques capable of characterizing the defect evolution in semiconductor heteroepitaxy. Published under an exclusive license by AIP Publishing.

Automated summary

In this study, the structural and optical properties of heteroepitaxial II-VI CdTe (211)B buffer layers with strained CdZnTe/CdTe superlattice layers were investigated using non-destructive methods, including high-resolution x-ray diffraction, cathodoluminescence, and photoluminescence spectroscopy. The results showed that the superlattice layers had coherent strain and better in-plane lattice-matching with HgCdTe. The cross-sectional cathodoluminescence and photoluminescence measurements confirmed the coherent growth of the superlattice layers and their dislocation filtering effects. The techniques used in CdTe layers were well correlated with the dislocation density. These non-destructive methods have the potential to be developed into general-purpose techniques for characterizing defect evolution in semiconductor heteroepitaxy.