Investigation of the Raman scattering spectra of ZnGeP2 crystals

ZnGeP₂ crystals with different optical breakdown thresholds studied in this work. The Raman spectra of the crystals were obtained using the inVia Reflex system with an excitation wavelength of 785 nm. It is shown that the obtained peaks at frequencies of 141.6, 203.3, 327.4, and 402.4 cm^–1 correspond to the vibrational frequencies of the ZnGeP₂ lattice for wafers cut parallel to the (100) crystallographic directions and the peaks at frequencies of 119.1, 245, 327.4, 357.1, 384.7, and 408.7 cm^–1 to the (001) crystallographic directions. No correlation with the breakdown threshold was found. This fact confirms the assumption that the breakdown threshold in a given spectral range is determined not by thermal mechanisms, but by the dielectric breakdown of the crystal surface. This work was supported by the Ministry of Science and Higher Education of the Russian Federation (V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Sciences).