Polarized optical properties in type-II ZnTe/CdSe multiple quantum wells induced by interface chemical bonds

Abstract

Photoluminescence (PL) and photoconductivity (PC) spectra were studied in type-II ZnTe/CdSe multiple quantum wells. It was found that the PL spectrum exhibits a strong in-plane polarization with respect to 〈011〉 axis with a polarization degree up to 30%. The degree of polarization does not depend on the excitation intensity and temperature, which excludes extrinsic mechanisms related to the observed in-plane anisotropy. The underlying mechanism of the observed polarization dependence of the optical properties was attributed to the inherent property of the orientation of chemical bonds in ZnTe/CdSe heterostructures with no common atom. In addition, the PC spectra also display a strong polarization dependence. Unlike the PL spectra, the PC response continuously covers a wide range of wavelengths arising from interface imperfections. We therefore point out that polarized PL and PC spectroscopies provide a unique way to probe the effects of the orientation of interface chemical bonds on semiconductor heterostructures.