ZnGeP_2的多晶合成与单晶生长研究

Polycrystal Synthesis and Single Crystal Growth of ZnGeP_2

采用富P配料工艺,通过改进的单温区合成法(MSTZM)合成出高纯、单相的ZnGeP2多晶原料。用改进垂直布里奇曼法(MVBM)生长出尺寸为Φ20mm×30mm的ZnGeP2单晶体。经X射线衍射分析、红外光谱分析、ZC36高阻仪测试表明:晶体完整性好,具有黄铜矿结构,晶格常数a=b=0.5463nm,c=1.0709nm。晶体的透光范围为0.65～12.5μm。厚度为2mm的晶片在2～12μm范围内的平均红外透过率达55%以上,电阻率为6×107Ω·cm,计算2.05μm和10.6μm处的吸收系数分别为0.017cm-1和0.21cm-1。

High-purity and single-phase ZnGeP2（ZGP） polycrystal was synthesized by Zn, Ge, and red P elements （99.9999%） according to the stoichiometry of ZnGeP2 with an excess of 0.2% P through a Modified Single-Temperature Zone Method（MSTZM）. An integral ZnGeP2 single crystal with size of Φ20mm×30mm was obtained by Modi- fied Vertical Bridgman Method （MVBM）. The as-grown crystals were characterized by X-ray diffraction（XRD）, ZC36 Megger, Uhraviolet（UV） and Infrared（IR） spectroscopy. XRD analysis indicates ZnGeP2 crystal is ehalcopyrite structure, the lattice constants of a and e are 0.546 3 nm and 1.070 9 nm, respectively. The transparency range of a ZGP wafer with 2 mm thickness is 0.65-12.5 μm, the infrared transmission is above 55% in the spectral region of 2-12 μm. Resistivity of the crystal is about 10^7 cm magnitude. The value of absorption eoefficient（α） at 2.05 μm and 10.6 μm are 0.017 cm^-1 and 0.21 cm^-1, respectively. These results demonstrate that the quality of the as-grown crystal is high enough for applications in infrared nonlinear devices.