Evidence of High Electron Mobility in CdGeAs2 Single Crystals

AbstractCdGeAs2 single crystals were prepared by low temperature crystallization from a nonstoichiometric melt. The results of the first study of the temperature dependencies of the electrical conductivity and the Hall coefficient of n-type CdGeAs2 single crystals prepared by this new technique are reported. All the as-grown crystals show n-type conductivity. These single crystals had free electron concentrations of (1 - 2) 1018 cm−3 and Hall mobilities of more than 10000 cm2/(Vs) at T=300 K. These room temperature electron mobility values are four times larger than previously reported. In the high temperature region (T> 150K), the temperature dependence of the Hall mobility exhibited a behavior characteristic of phonon scattering. Below 150 K, a deviation from this behavior indicated an increasing contribution of static lattice defects to scattering. The Hall mobility in these crystals was found to reach ∼ 36000 cm2/( V· s ) at 77 K. The first photosensitive n-type CdGeAs2/n-type InSe heterostructures were constructed by contact methods. Photosensitivities of 70-100 V/were observed. This is substantially better than for previous structures using conventionally grown CdGeAs2 and indicates the high quality of the crystals. It is concluded that the low temperature growth technique is promising for the preparation of more perfect CdGeAs2crystals.