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 mecha...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.展开更多
By the method of descending crucible with rotation, crack-free CdGeAs2single crystals of U15 mm 950 mm were grown in a furnace with three independen heating zones after optimizing the temperature field, and the descen...By the method of descending crucible with rotation, crack-free CdGeAs2single crystals of U15 mm 950 mm were grown in a furnace with three independen heating zones after optimizing the temperature field, and the descending and rotational speed to meet the need of CdGeAs2crystal growth. The properties of as-grown crysta were characterized by a variety of techniques. The results of X-ray diffraction（XRD） show that there are two cleavage faces, which are（110） and（101）. The peaks are in high intensity and good symmetry, which demonstrates that the crystal is integral in structure and well crystallized. The energy-dispersive spectrometry results indicate that the wafer of the CdGeAs2crystal is closer to the stoichiometry The IR transmittance of the wafer is ＊48.6 % at 5.5 lm, and the maximum value is up to 51.6 % in the range of2.3–18.0 lm. Etch pits of（001） face are observed and the density of the etch pits is evaluated to be 1 9 105cm-2.展开更多
采用改进的布里奇曼法生长出尺寸为Φ15 mm×45 mm,外观完整无开裂的Cd Ge As2单晶体。为了提高器件的使用性能,需要对晶体进行表面处理,主要对Cd Ge As2晶片表面的抛光技术进行了研究。通过对解理面切割分析得到(101)晶面,机械抛...采用改进的布里奇曼法生长出尺寸为Φ15 mm×45 mm,外观完整无开裂的Cd Ge As2单晶体。为了提高器件的使用性能,需要对晶体进行表面处理,主要对Cd Ge As2晶片表面的抛光技术进行了研究。通过对解理面切割分析得到(101)晶面,机械抛光后进行了XPS分析。对该晶面采用溴甲醇溶液进行腐蚀抛光,采用XRD回摆及光学显微镜对不同抛光时间的试样进行观测。结果表明,CGA晶体的(101)晶面在常温下采用溴甲醇溶液腐蚀50 s后,晶片表面光滑无划痕,并且具有半峰宽较小的回摆曲线,同时计算得到Cd Ge As2晶体的表面损伤层厚度。展开更多
The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory （DFT）. Mulli...The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory （DFT）. Mulliken population analysis showed that atomic orbital hybridization occurs when forming chemical bonds. The relationship between inter-band transition and optical properties was analyzed to provide a theoretical basis for investigating or controlling CdGeAs2 crystal defects.展开更多
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)
文摘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.
基金financially supported by the National Natural Science Foundation Key Programs of China (No. 50732005)the National High Technology Research and Development Program of China (No. 2007AA03Z443)
文摘By the method of descending crucible with rotation, crack-free CdGeAs2single crystals of U15 mm 950 mm were grown in a furnace with three independen heating zones after optimizing the temperature field, and the descending and rotational speed to meet the need of CdGeAs2crystal growth. The properties of as-grown crysta were characterized by a variety of techniques. The results of X-ray diffraction（XRD） show that there are two cleavage faces, which are（110） and（101）. The peaks are in high intensity and good symmetry, which demonstrates that the crystal is integral in structure and well crystallized. The energy-dispersive spectrometry results indicate that the wafer of the CdGeAs2crystal is closer to the stoichiometry The IR transmittance of the wafer is ＊48.6 % at 5.5 lm, and the maximum value is up to 51.6 % in the range of2.3–18.0 lm. Etch pits of（001） face are observed and the density of the etch pits is evaluated to be 1 9 105cm-2.
基金National Natural Science Foundation of China(50732005)National High Technology Research and Development Program of China(2007AA03Z443)
文摘采用改进的布里奇曼法生长出尺寸为Φ15 mm×45 mm,外观完整无开裂的Cd Ge As2单晶体。为了提高器件的使用性能,需要对晶体进行表面处理,主要对Cd Ge As2晶片表面的抛光技术进行了研究。通过对解理面切割分析得到(101)晶面,机械抛光后进行了XPS分析。对该晶面采用溴甲醇溶液进行腐蚀抛光,采用XRD回摆及光学显微镜对不同抛光时间的试样进行观测。结果表明,CGA晶体的(101)晶面在常温下采用溴甲醇溶液腐蚀50 s后,晶片表面光滑无划痕,并且具有半峰宽较小的回摆曲线,同时计算得到Cd Ge As2晶体的表面损伤层厚度。
基金supported by the National Natural Science Foundation of China (E5057201)Heilongjiang Provincial Scientific and Technological Projects
文摘The electronic structure and optical properties of CdGeAs2 were calculated by the first principle method using ultra-soft pseudo-potential approach of the plane wave based upon density functional theory （DFT）. Mulliken population analysis showed that atomic orbital hybridization occurs when forming chemical bonds. The relationship between inter-band transition and optical properties was analyzed to provide a theoretical basis for investigating or controlling CdGeAs2 crystal defects.
