Electrical and crystallographic characterization of CdTe grown by the vapor transport method

Abstract

Crystallographic and electrical characterization techniques were performed on CdTe single crystal samples grown by the sublimation and physical vapor transport (SPVT) technique. The SPVT growth process described here has resulted in the routine growth of 45–50 mm diameter, 250–300 g boules of single crystal CdTe. As-grown material is p-type in the 5–10 ω cm range. Etch pit densities (EPD) are nominally 7×10 4 cm -2 along the [111] growth direction and 3×10 4 cm -2 along the [ 1 11] direction. X-ray full width at half maximum (FWHM) on recent samples is 8.6 arc sec compared to 8.5 arc sec theoretical. The as-grown p-type material displays room temperature mobility in the 80–90 cm 2 V -1 s -1 range and displays acceptor levels due to Cd vacancies 0.045 eV above the valence band and due to Cd vacancy-donor complexes 0.16 eV above the valence band. The boules are a constant diameter over most of their length (∼5.5 cm) and generally display no visual or X-ray detectable twins or grain boundaries.