Crystal growth and dislocation etch pits observation of chalcopyrite CdSiP2

Abstract

CdSiP2 is the only crystal that can offer Non-critical Phase Matching (NCPM) for a 1064nm pumped optical parametric oscillation (OPO) with idler output in the 6μm range. In this paper, a large, crack-free CdSiP2 single crystal measuring 18mm in diameter and 65mm in length was successfully grown by the Vertical Bridgman method (MVB) with an explosion-proof quartz ampoule. The results of lattice parameters, element composition and IR transmittance of the as-grown crystal characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS) and Fourier transformation infrared spectrometer (FTIR) showed the as grown crystal crystallized well and the absorption coefficients at 4878cm−1 and 2500cm−1 were 0.14cm−1 and 0.06cm−1. Moreover, a new etchant composed of Br2, HCl, HNO3, CH3OH and H2O (1:800:800:400:400 in volume ratio) was prepared and the dislocation etch pits on oriented faces of as-grown CdSiP2 crystal were observed for the first time. It is found the etch pits are in rectangular structure on the (101) face, but in trigonal pyramid structure on (312) face. According to the quantities of the etch pits, the average densities of dislocation were evaluated to be 2.28×105/cm2 and 1.4×105/cm2, respectively.