Abstract: ZnGeP₂ crystal has several absorption peaks in 1 μm to 2.5 μm, which are mainly caused by point defect V_P, Ge_Zn and V_Zn. These optical absorption seriously affect the applied performance in optical parametric oscillator. Therefore, theoretical calculation of electron irradiation based on the electron-nucleus scattering theory were executed to understand the effective experiment condition. The ZnGeP₂ single crystal was grown by Bridgman method, then the infrared absorption spectrum, Hall coefficient and carrier concentration of as grown ZnGeP₂, annealed ZnGeP₂ and irradiated ZnGeP₂ were tested by infrared spectrometer and physical performance mearsurement system. The results show that annealed treatment can effectively reduce the optical absorption of ZnGeP₂ crystal near 1.2 μm and 1.4 μm, while electron irradiation treatment is beneficial to reduce the optical absorption of ZnGeP₂ crystal near 2.0 μm, which is consistent with the calculated results.

Key words: ZnGeP₂, point defect, Bridgman method, IR absorption spectrum, Hall effect