Fabrication of high resolution X/γ-ray detectors using laser-induced doping of CdTe in liquid

The uncooled X/γ-ray detectors with high energy resolution (FWHM <; 1% at 662 KeV) have been obtained. The detectors were developed as M-p-n structured In/CdTe/Au diodes using solid-phase doping of the surface region of high resistivity p-like CdTe semiconductor crystals laser irradiation of an In dopant film predeposited on the CdTe(111)B surface. The key feature was that the In/CdTe samples were subjected to multiple irradiation with nanosecond laser pulses in a liquid medium. Using water as an environment under laser-induced doping allowed to increase laser pulse energy density and number of laser shots that resulted in the formation of a shallow and abrupt p-n junction. The created high barrier makes it possible to apply high bias voltage (up to 1000 V) without a significant increase in the leakage current and thus to extend the depletion region and improve the carrier charge collection in the M-p-n diodes. The fabrication technology has provided a relatively high yield of the X/γ-ray detectors with acceptable characteristics.