Abstract
Optimum growth conditions for growing pure undoped single crystals of CdTe from a Te-rich solution by the travelling heater method are investigated. For the growing apparatus employed, the optimum conditions are determined to be the growth temperature around 675°C and the growth rate of 3 mm/day. When the Cd over-pressure over the Te-solution is controlled during the crystal growth, the room-temperature resistivity can be increased to approximately 107 Ω·cm. Characterization of the crystals is carried out by means of ion microprobe mass analysis, Hall and photoluminescence measurements, time-of-flight measurement and γ-ray detection. The surface-barrier detectors are made using undoped crystals grown under the optimum Cd over-pressure. It is found that the energy resolution (FWHM) at room temperature is approximately 12 keV for 122 keV gamma-ray from 57Co and 8 keV for 59.5 keV gamma-ray from 241Am.