Characterization of vertical Bridgman grown Cd0.9Zn0.1Te0.97Se0.03 single crystal for room-temperature radiation detection

We report a modified vertical Bridgman method to grow Cd0.9Zn0.1Te0.97Se0.03 (CZTS) single crystals using in-house zone-refined 7 N (99.99999%) purity elemental precursors for room-temperature radiation detection. CZTS is an economic yet high performance alternative to expensive CdZnTe (CZT) detectors for room-temperature gamma-ray detection. Radiation detector in planar geometry has been fabricated on an 11.0 x 11.0 x 3.0 mm(3) CZTS single crystal. A bulk resistivity of 10(10) omega.cm has been achieved without using any compensating dopant. The elemental composition of the grown crystal has been examined using energy-dispersive X-ray (EDX) analysis. Powder X-ray diffraction (XRD) showed formation of zincblende phase with a lattice constant of 6.447 angstrom, and sharp peaks confirmed the formation of highly crystalline single-phase CZTS crystals. A modified Vegard's law has been applied to calculate the atomic percentage of Se in the grown crystals from the XRD patterns and compared with the intended and the measured stoichiometry. The electron mobility-lifetime (mu tau) product and the drift mobility have been calculated to be 1.5 x 10(-3) cm(2)/V and 710 cm(2)/V.s, respectively, using alpha spectroscopy. The presented vertical Bridgman growth method uses a single pass through the controlled heating zone in contrast to the previously reported multiple pass growth techniques, thus, reducing the growth duration by two third which would help to further reduce the cost of production of CZTS-based room-temperature detectors.

Automated summary

A modified vertical Bridgman method was used to grow CZTS single crystals for room-temperature radiation detection, achieving high resistivity, crystallinity, and desired elemental composition. The growth technique reduced duration and production costs of CZTS-based detectors.