Growth of CdSiP2 single crystals by double-walled quartz ampoule technique

Abstract

A CdSiP2 single crystal measuring 15mm in diameter and 35mm in length was grown by the modified vertical Bridgman method adopting a specially designed double-walled quartz ampoule. The as-grown crystal was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), infrared (IR) and visible–near infrared (VIS–NIR) spectrophotometers and X-ray photoelectron spectroscopy (XPS). It is found that multiple diffraction peaks of a (101) cleavage face are evident and parallel growth steps on the face are observed. The XRF result indicates that the chemical composition of the as-grown crystal is close to the ideal stoichiometry. The IR transmittance of a sample with 2mm thickness is about 48% in the range from 10,000 to 1500cm−1. The VIS–NIR spectrum shows that the short wave absorption edge is at about 576nm and the calculated band gap is about 2.15eV. The binding energies of the Cd 3d3/2, Cd 3d5/2, Si 3d and P 2p core levels are determined to be 411.8eV, 405.1eV, 101.1eV and 129.5eV, respectively. These results show that the quality of the as-grown crystal is good and the double-walled quartz ampoule technique is promising for the growth of high-quality CdSiP2 single crystals.