Optical absorption and photoconductivity in gamma-irradiated zinc selenide crystals

The possibility of radiation-induced enhancement of photoconductivity (σph) in crystalline zinc selenide (ZnSe) has been studied. The electron concentration in the initial ZnSe:O crystal was N Eg = 1.26 × 1016 cm−3 as determined from the optical density of the sample at E g = 2.58 eV. The irradiation of the ZnSe:O crystal by gamma-photons from 60Co source to a dose of 106 Gy leads to the creation of five new energy levels (Γ6v, 5.76 eV; L 1.3v, 4.85 eV; Zni, 3.34 eV; OSe, 3.13 eV; X, 2.72 eV), a decrease in the electron concentration to N Eg = 0.63 × 1016 cm−3, and a twofold increase in σph. The doping with Te to 0.2 wt % also creates the L 1.3v level and increases N Eg to 2.02 × 1016 cm−3 and σph to 2.01 × 10−10 Ω−1. The irradiation of Te-doped crystals leads to the creation of an additional resonant level (Zni, 3.34 eV) and a two-fold increase in σph. An increase in the content of Te to 0.5 wt % results in a shift of the Zni level to 3.39 eV and a growth in the conductivity to σph = 7.64 × 10−10 Ω−1. However, the gamma-irradiation of these crystals leads to decomposition of this center and to a decrease in the photoconductivity.

Ҳали таржима қилинмаган