硫镓银晶体的化学腐蚀研究

采用改进的垂直布里奇曼(Bridgman)法自发成核生长AgGaS2晶体,在生长初期对生长安瓿籽晶袋进行上提回熔,生长出外观完整、无裂纹的大尺寸AgCaS2单晶体.采用XRD对晶体进行分析,获得了(112)、(001)和(101)面的高强度尖锐衍射峰.采用不同配比的腐蚀剂对晶体(101)、(112)及(001)晶面进行化学腐蚀,然后采用金相显微镜和扫描电镜观察,结果显示,(101)晶面蚀坑为清晰的近似三角形的四边形蚀坑,(112)晶面蚀坑为清晰的近似三角锥形,(001)晶面则呈现互相垂直的腐蚀线.初步分析了不同蚀坑的形成原因,计算出(101)和(112)面蚀坑密度约为105/cm2数量级.结果表明,改进方法生长出的大尺寸AgGaS2单晶体结构完整、位错密度低,质量较好.

Chemical Etching Research on AgGaS2 Crystals

An integral,crack-free and large-sized AgGaS2 single crystal was obtained by the modified self-seeding Bridgman method.The technique of ascending the growth ampoule and holding the tip in specific height for a period of time at the beginning of growth was adopted and was proved to be effective for promoting geometric elimination.The grown crystal was characterized using the powder X-ray diffraction(XRD).Sharp and intense XRD spectra of(101),(112) and(001) faces were obtained.Etchants of different mole ratios were used to etch various faces of AgGaS2 crystal.Quadrilateral etch pits appear on(101) faces,triangular etch pits appear on(112) faces,and morphology on(001) face of AgGaS2 crystal exhibits vertical etch lines.Etch pits on(101) and(112) faces observed by SEM exhibit differentiated quadrilateral and triangular shapes.The densities of etch pits were calculated to be at the order of 105/cm2 magnitude.The results show that the large-sized AgGaS2 single crystal obtained by modified method has a low defect density and is of good quality.