Progress in chalcopyrite semiconductor of cadmium germanium arsenide

Cadmium germanium arsenide, CdGeAs₂, is a ternary chalcopyrite semiconductor known for having rather high nonlinear optical coefficients (236pm / V), making it attractive for CO₂-doubier. For a long time, conventional growth method yielded severely-crack due to anisotropy in thermal expansion along the a- and c-axes. CdGeAs₂ crystal has a strong absorption at 5. 5μm which related to a native acceptor defect, the absorption can decrease the efficient of CdGeAs₂ frequency-doubling. This paper reviewed different methods of single crystal growth as well as absorption defect, and pointed out that doping with donor impurities are the main research field for single crystal growth at last.