Growth of In-doped CdTe from Te excess solution and its characteristics as a γ-ray detector

Abstract

CdTe single crystals were grown from a Te excess solution and In was added as a donor dopant in order to compensate the native defects such as a cadmium vacancy V Cd introduced through the growth process. The as-grown doped crystals showed n-type electrical conductivity which varied from 10 -4 to 10 -8 (ohm cm) -1 and seemed to have many complex trapping centers (V 2- Cd.2In + Cd), consisting of singly ionized In donors on the Cd site (In + Cd) and negatively charged cadmium vacancies (V 2- Cd). Surface barrier type γ-ray detectors having a size of about 1×3×3 mm 3 were fabricated from the crystals and they showed a good response for 59.5 keV γ-rays of 241Am with a resolution expressed as FWHM (full width at half maximum) of 7.0 keV. The characteristics of the nuclear response were compared with that of undoped CdTe crystals grown by the present authors using the travelling solvent method (TSM).