采用单温区法合成了CdSiP2(CSP)多晶原料,然后采用垂直布里奇曼法生长了大尺寸的CSP单晶。采用扫描电子显微镜、EDS对晶体中光散射颗粒的尺寸、形貌和成分进行了观察和检测。测试结果表明,所生长的CSP晶体中的光散射颗粒呈近椭圆形,尺寸为2~8μm,主要成分为Si,含量占88%以上。对CSP多晶合成的反应机理研究表明,此第二相颗粒是由于合成时多晶料中残留有少量未反应的Si单质所致。通过合成工艺的改进,有效地减少了晶体中Si散射颗粒的残留,制备出了高透明性的CSP单晶体。
Polycrystalline charges of CdSiP2(CSP) were synthesized by direct reaction method using P, Si, and Cd elements as the initial materials. Single crystals with the dimension of 8 mm in diameter and 40 mm in length were successfully grown by vertical Bridgman method. The dimension and the composition of the optical scatter particles in the CSP crystals were identified by SEM measurement. The results show that most of optical scattering particles are round-shaped with dimension of 2–8 μm. The EDS measurement result shows that the atomic percent of Si in the optical scattering particles is over 88%. The synthesis mechanism of CSP by single temperature zone method was studied by powder XRD. The results show that there is some unreacted silicon left when synthsized process is carried out below 1150℃. By optimizing the synthesis parameters and the Si inclusions were successfully restrained and the high optical quality CSP single crystal was obtained.