Spectroscopic properties of ZnTe:Cr crystal grown by ACRT-Te solvent method

ZnTe:Cr crystal was grown by a modified ACRT-Te solvent method and its spectroscopic properties were characterized. The UV-Vis-NIR transmission spectrum shows two strong absorptions related to Cr²⁺ located at the wavelength of 800 nm and 1790 nm as well as the V_Zn-related absorption in the range of 570-750 nm. Low temperature PL spectrum indicates two peak bands at near 530 nm and 595-630 nm assigned to near band edge (NBE) and self-activation (SA) emissions. Further analysis demonstrates that the NBE emission is composed of acceptor-bound-excition (A₁, X) band, electron-acceptor band (e, A) and donor-acceptor-pair (DAP) band. Temperature-dependent PL spectrum of NBE peak is fitted by Arrhenius formula, from which the thermal quenching activation energies of ZnTe:Cr crystal at low (<50 K) and high (>50 K) temperatures are obtained to be 3.87 meV and 59.53 meV, respectively. Infrared fluorescence spectrum indicates that ZnTe:Cr crystal produces fluorescence emission band in the range of 2-2.6 μm at room-temperature, with the fluorescence lifetime of 1.0×10^-6 s.