The dependence of the strain effects on the ZnTe layer thicknesses in ZnTe/GaAs heterostructures

Photoluminescence (PL) and spectroscopic ellipsometry measurements on ZnTe/GaAs strained heterostructures grown by molecular beam epitaxy were carried out to investigate the strain effect depending on the ZnTe epitaxial layer thickness. PL spectra show that the PL peaks corresponding to the excitons bound to neutral acceptors shift toward the higher-energy side with increasing the ZnTe film thickness. As the strain increases, the value of the critical-point energy shift obtained from the spectroscopic ellipsomerty increases. The strains in the ZnTe layers grown on GaAs substrates are expected to decrease with increasing the ZnTe layer thickness. These results indicate that the strains in the ZnTe layers grown on GaAs substrates are strongly dependent on the ZnTe layer thickness.