关键词: 半导体晶体, CdGeAs₂晶体, 类籽晶技术, 布里奇曼法, 单晶生长, 多晶合成, 变温霍尔效应, 红外透过谱

Abstract: CdGeAs₂ polycrystalline was synthesized by temperature oscillation method, and an integral and crack-free CdGeAs₂ single crystal with size of ϕ28 mm×65 mm was grown by the modified vertical Bridgman method. The synthesized polycrystalline was characterized by X-ray diffraction (XRD). The CdGeAs₂ wafer cut with a diamond cylindrical cutter was characterized by energy dispersive spectrometer (EDS) and IR Prestige-21 spectrophotometer. The results show that the synthesized product is CdGeAs₂ polycrystalline with tetragonal chalcopyrite structure, and the atomic percentage of the wafer is close to the ideal stoichiometric ratio. The absorption coefficient of the as-grown CdGeAs₂ crystal at 11.3 μm is 0.117 cm^-1 and the fitted band gap is 0.52 eV. Temperature dependent (110 K to 300 K) Hall measurement shows that the sample is p-type conductive in the temperature range from 110 K to 300 K. The carrier concentration p_H increases and the Hall coefficient R_H decreases respectively with the increase of temperature, while the Hall mobility μ_H is almost unchanged. Fitting and calculating results show that the acceptor ionization energy E_A is 0.305 eV in the crystal, and the possible acceptor defects in CdGeAs₂ single crystal was further analyzed.

Key words: semiconductor crystal, CdGeAs₂crystal, seed like technology, Bridgman method, single crystal growth, polycrystalline synthesis, temperature dependent hall measurement, IR transmission spectrum