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
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
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.
