硒化镉 (CdSe)晶体有两种结构 ,一种是六方结构 ,6mm点群 ;另一种是立方结构 ,43m点群。其中六方结构的硒化镉晶体是一种新型的性能优异的室温半导体探测器材料。其能隙较大 (Eg =1 .75eV) ,电阻率较高 ( 1 0 12 Ω·cm) ,在室温高偏压下 ,漏电流很小 ,电子和空隙迁移率较大 ( μc=72 0cm2 /V·s,μh=75cm2 /V·s) ,电子俘获浓度大 (Nt=1 0 14 /cm3 ) ,电荷收集效率高 ,稳定性好 ,没有像在CdTe和HgI2 晶体中观测到的极化现象 ,力学、热学和化学稳定性能也优于HgI2 晶体。因此 ,CdSe晶体是一种有希望替代CdTe和HgI2 的室温核辐射探测器新材料 ,用其制作的探测器和各种谱仪可广泛用于探矿、无损检测、核医学、环境监测、军事和空间宇航技术等领域。CdSe晶体熔点高达 1 2 39℃ ,在熔点附近平衡蒸汽压高达十几个大气压 ,因此其单晶体难以用常规的熔体法生长。我们采用水平气相输运法进行了CdSe单晶体生长试验 ,对其在不同温度和温度梯度下的结晶特性进行了研究 ,确定出生长六方CdSe单晶的较好工艺参量为 :源区蒸发温度 1 1 0 0℃ ,生长界面附近温度梯度为 6℃ /cm ,生长区与源区的距离大约为 1 2cm。在此条件下 ,生长出1 0× 1 2mm外观完整 ,有自然显露晶面的CdSe晶锭。对生长的CdTe单晶经X射线衍射分析表 CdSe crystals have two kinds of structures, one is hexagonal structure, 6mm point group; the other is cubic structure, 43m point group. Among them, the hexagonal structure of CdSe crystal is a new type of excellent room temperature semiconductor detector material. (Eg = 1 .75eV) and high resistivity (1012Ω · cm), the leakage current is very small and the mobility of electrons and voids is relatively high at room temperature high bias (μc = 72 0cm2 / V · s, μh = 75cm2 / V · s), high electron trapping concentration (Nt = 1014 / cm3), high charge collection efficiency, good stability and no polarization as observed in CdTe and HgI2 crystals Phenomena, mechanics, thermal and chemical stability are also better than HgI2 crystals. Therefore, CdSe crystal is a new promising room temperature nuclear radiation detector that can replace CdTe and HgI2. It can be widely used in prospecting, non-destructive testing, nuclear medicine, environmental monitoring, military and military applications Space aerospace technology and other fields. The melting point of CdSe crystals is as high as 1239 ℃. The equilibrium vapor pressure in the vicinity of the melting point is as high as more than ten atmospheres. Therefore, it is difficult to grow the single crystal with the conventional melt method. The CdSe single crystal growth experiments were carried out by horizontal vapor transport method. The crystallization characteristics under different temperature and temperature gradients were studied. The better technological parameters of the grown hexagonal CdSe single crystals were determined as follows: the source region evaporation temperature 11 0 0 ℃, the temperature gradient near the growth interface is 6 ℃ / cm, the distance between the growth area and the source area is about 12cm. Under these conditions, the growth of 1 × 12mm appearance of a complete, naturally revealing crystal plane CdSe ingot. The growth of CdTe single crystal by X-ray diffraction analysis table