The relationship between stress and photoluminescence of Cd_0.96Zn_0.04Te single crystal

Photoluminescence (PL) and high-resolution X-ray diffraction (HRXRD) experiments have been carried out on strained Cd_0.96Zn_0.04Te single crystals to reveal the correlation between luminescence spectrum and stress in CdZnTe wafers. The tensile stress introduced by quenching was measured by X-ray diffraction methods. The photoluminescence spectra were found to move to higher energies, and the intensity of neutral donor bound exciton (D⁰, X) peak of CdZnTe wafer was increased after quenching. The reasons for these variations are suggested to be determined by the change of the energy band gap E_g of the CdZnTe wafer and the increase of crystal defects. The in-plane biaxial stress of 1 GPa results in a shift of the excitonic PL spectrum of 7.05-12.03 meV. In particular, the tensile strain reduces the formation energy of Te_Cd antisite defects, which are the shallow donors located at 0.01 eV below the conduction band. Therefore, high density of Te_Cd antisite defects demonstrated by the higher (D⁰, X) emission are generated due to the high tensile strain in the quenched specimen.