Optimal photoluminescence spectrum from Ti-doped ZnTe

Abstract

In this paper, experimental conditions are carefully optimized of excitation energy, power and degree of focus, water disturbance and temperature to overcome th e difficulties involved in photoluminescence (PL) study of ZnTe:Ti. It is illust rated that:(i)Higher PL intensity is accessible with excitation energy just belo w the band-gap energy of ZnTe.(ii)Water disturbance not only changes the relative intensities of the PL lines but also increases the measuring error of the transition energies. (iii) Excitation with relatively stronger focus produces better PL spectrum. Two zero-phonon lines (ZPLs) are unambiguously identified at 3903.5 and 3905.9 cm-1, respectively. They are ascribed to be due to Ti3+ in ZnTe with the aid of the crystal field theory, the transition energy, the energy difference of the two ZPLs and the temperature dependence of the relative intensity of the ZPLs. It is the first evidence from PL study for the Ti3+ in Ⅱ-Ⅵ compound semiconductors.