硒镓银（AgGaSe_2）晶体的热处理研究

Heat Treatment Study on Silver Selenogallate(AgGaSe_2)Crystals

用改进的布里奇曼法生长出Φ１８×３０ｍｍＡｇＧａＳｅ＿２单晶体，并通过在共晶温度点以下迅速冷却的淬火热处理或在Ａｇ＿２Ｓｅ及ＡｇＧａＳｅ＿２粉末围裹下的退火热处理，显著改善了ＡｇＧａＳｅ＿２晶体的透明度。其中尤以在ＡｇＧａＳｅ＿２多晶粉末围裹下的退火效果为佳。红外显微观察及红外透过曲线测量表明：晶体中引起红外吸收的微观散射中心呈层状分布，致使晶体的红外透过率与方向有关。

In this paper,a Φ18×30mm AgGaSe_2 crystal is grown by the modified Bridgman technique. Three heat treatment methods by using quenching technique in which the crystal is rapidly cooled from temperature just below the eutectic point or by annealing with Ag_2Se or AgGaSe_2 powder on the as-grown AgGaSe_2 crystal have been carried out.The results show that the optical transmittance of the AgGaSe_2 crystal is markedly improved after the heat treatment.Among the three methods,annealing the crystal in the powder of AgGaSe_2 polycrystal is the most effective to improve the quality of the crystal. The lamellar scattering centers have been observed in the annealed crystal by an infrared microscope. These centers result in dependence of the transmittance on the direction of crystal.