Surface treatments of CdGeAs2 single crystals  

作　　者：Wei Huang Bei-Jun Zhao Shi-Fu Zhu Zhi-Yu He Bao-Jun Chen Zhen Zhen Yun-Xiao Pu 

机构地区：[1]College of Materials Science and Engineering,Sichuan University

出　　处：《Rare Metals》2019年第7期683-688,共6页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (No. 50732005);the National High Technology Research and Development Program of China (No. 007AA03Z443)

摘　　要：The performances of second harmonic gen eration (SHG) and optical parametric oscillator (OPO) in CdGeAs2 crystal are strongly influenced by surface quality. In this paper, the surfaces of samples were treated by mechanical polishing (MP), chemical polishing (CP), chemical-mechanical polishing (CMP) and CP following CMP closely (CMP + CP). Then, the surface state was characterized by optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM measurements show that an ultra-smooth surface is achieved after CMP + CP treatment and the roughness value is 0.98 nm. Meanwhile, the roughness of the surfaces treated by MP, CP and CMP are 4.53, 2.83 and 1.38 nm, respectively. By XRD rocking curves, the diffraction peak which belongs to the wafer treated by CMP + CP is the highest in intensity and best symmetrical in shape. XPS analysis indicates that Ge4+ proportions of GeO2 in total Ge content of CdGeAs2 wafers' surface after MP, CP, CMP and CMP + CP treatment are 27.6%, 42.8%, 6.1% and 30.3%, respectively.The performances of second harmonic generation（SHG）and optical parametric oscillator（OPO）in CdGeAs2 crystal are strongly influenced by surface quality.In this paper,the surfaces of samples were treated by mechanical polishing（MP）,chemical polishing（CP）,chemical-mechanical polishing（CMP）and CP following CMP closely（CMP + CP）.Then,the surface state was characterized by optical microscopy（OM）,scanning electron microscopy（SEM）,atomic force microscopy（AFM）and X-ray photoelectron spectroscopy（XPS）.AFM measurements show that an ultra-smooth surface is achieved after CMP+ CP treatment and the roughness value is 0.98 nm.Meanwhile,the roughness of the surfaces treated by MP,CP and CMP are 4.53,2.83 and 1.38 nm,respectively.By XRD rocking curves,the diffraction peak which belongs to the wafer treated by CMP+CP is the highest in intensity and best symmetrical in shape.XPS analysis indicates that Ge4+ proportions of GeO2 in total Ge content of CdGeAs2 wafers’ surface after MP,CP,CMP and CMP + CP treatment are 27.6%,42.8%,6.1% and 30.3%,respectively.

关 键 词：CdGeAs2 SINGLE CRYSTAL SURFACE TREATMENTS SURFACE ROUGHNESS 

分 类 号：TF[冶金工程]