Growth and characterization of large-size CdMgTe single crystals doped with different in amounts

Cadmium magnesium telluride (CdMgTe) is a very perspective material for room temperature radiation detectors. In this paper, two large-size Cd_0.95Mg_0.05Te ingots doped with different In amounts were grown by vertical Bridgman method under Cd-compensated condition. It was found that the impurities were distributed inhomogeneously and In dopant mainly concentrated in the tail of two ingots. Compared with the ingot grown by doping with 5 ppm In, the ingot grown by doping with 10 ppm In had more uniform distribution of Mg element, higher IR transmittance, less Te inclusions and better crystal quality. FIB-TEM and HRTEM analysis showed that the size of Te precipitates was less than 10 nm, the composition of both crystals was rich in Cd and was single crystal with sphalerite structure. The type of dislocation was edge dislocation and the density was high. In addition, the maximum IR transmittance and highest resistivity were 64 % and 1.53 × 10¹⁰ Ω cm, respectively. The planar detector prepared with 10 ppm In doped crystal had an energy resolution of 19.6 % and a (μτ)_e value of 1.38 × 10⁻³ cm²/V, which could meet the requirements for high performance room-temperature radiation detector.