The effect of gamma-irradiation on the bandgap width of ZnSe

Exposure to gamma-radiation from a ⁶⁰Co source affects the exciton photoluminescence (PL) spectra of single crystal zinc selenide measured at 4.2 K. As the radiation dose increases, the exciton PL maximum first shifts toward higher energies, but then returns to the initial position (in the range of sufficiently high doses). It is concluded that this behavior is due to variations of the semiconductor bandgap width related to the radiation-stimulated solid-state recrystallization and the accumulation of radiation-induced point defects during exposure.