Depletion Region in Cr/CdTe/Au Schottky Diode X- and $\gamma$ -Ray Detectors

The electrical and spectral characteristics of the Cr/cadmium telluride (CdTe)/Au structures with a Schottky contact at the Cr-CdTe interface and near ohmic contact at the Au-CdTe interface were studied. The Schottky diodes were fabricated using high-resistivity CdTe(111) single-crystal wafers with different thicknesses (0.5-2 mm) after preliminary chemical etching and also additional surface treatment by Ar-ion bombardment was employed. Electronic parameters such as the concentration of uncompensated impurities, width of the space-charge region, and the thickness of the depletion region were calculated based on the comparison of the voltage dependences of the photopeak heights in the
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Am isotope spectra excited from the Schottky contact side and ohmic contact side, respectively. The obtained Cr/CdTe/Au Schottky diodes with low leakage current [a few nanoampere (nA) at 1000-1500 V] show promise as high-energy resolution spectroscopic X-/gamma (γ)-ray detectors.