Influence of high-fluence electron irradiation on the band gap, Raman spectra, and microhardness of ZnSe

Abstract The influence of high-fluence electron irradiation on the optical and mechanical properties of ZnSe single crystals was systematically investigated. ZnSe samples synthesized via chemical vapor deposition were irradiated with 2 MeV electrons at fluences up to 2.5 × 10 17 electrons cm −2 . The optical band gap, Raman spectra, and microhardness of the samples were analyzed before and after irradiation. The results demonstrate that electron irradiation induces a decrease in the ZnSe band gap from 2.596 ± 0.002 eV to 2.580 ± 0.002 eV, attributed to the formation of irradiation-induced defects and associated sub-bandgap states. Raman spectroscopy revealed an increase in the intensity of the longitudinal optical (LO) phonon mode at 251 cm −1 and a reduction in the transverse optical (TO) mode at 205 cm −1 , indicating defect-induced modifications in phonon scattering and lattice dynamics. Additionally, microhardness measurements showed an exponential increase of 17.3%, suggesting that irradiation-induced defect interactions and changes in dislocation density contribute to mechanical strengthening. These findings provide valuable insights into the effects of electron irradiation on ZnSe and offer a pathway for tailoring its optical and mechanical properties for radiation-resistant optoelectronic applications.