CdGeAs_2多晶合成与单晶生长研究

Polycrystal Synthesis and Single Crystal Growth of CdGeAs_2

对新型中红外非线性光学材料CdGeAs2的多品合成和单品生长进行了研究．以高纯（99．9999％）As、Ge、Cd为原料，按照CdGeAs，化学计量比并适当富Cd、As配料，采用机械振荡与熔体温度振荡相结合的方法合成出CdGeAs2多品材料，使用改进的坩埚下降法生长山Ф15mm×45mm、外观完整无开裂的CdGeAs2单晶体．XRD全谱拟合精修、红外傅里叶分光光度计测试分析表明：合成的CdGeAs2晶体具有单相四方黄铜矿结构，晶格常数为a=b=0．5946nm，c=1．1217nm；生长出的CdGeAs2单晶体结构完整，结品性好，晶体的易解理面为（101）面，红外透明范围589－4250cm^-1，拟合计算出CdGeAs2晶体的禁带宽度为0．67eV．

CdGeAs2 polycrystal was synthesized by the raw materials of 99.9999% Cd, Ge and As in stoichiometfie weights with proper excess of Cd and As through mechanical and temperature oscillation of melt（MTOM）. An integral, crack free CdGeAs2 single crystal with size of Ф15 mm×40 mm was obtained by modified vertical de- scending cubic technique. The CdGeAs2 polycrystal and as-grown crystals were characterized by X-ray diffraction and infrared spectroscopy. XRD riteveld analysis indicates that the synthetic product is high-purity CdGeAs2 polycrystal in chalcopyrite structure, the lattice constants of a and c are 0.5946nm and 1.1217nm, respectively. The as-grown crystal is integrated in structure and crystallized well. It is also found that the cleavage plane of the crystal is （101）. CdGeAs2 wafer with 1.0 mm thickness is transparent in range of 589-4250cm^-1, and the band width is calculated to be 0.67eV.