Self-powered solar-blind ultrafast UV-C diamond detectors with asymmetric Schottky contacts

Single-crystal chemical vapour deposition (CVD) diamond samples with asymmetric Schottky contacts were used for the fabrication of vertical metal-semiconductor-metal detectors for deep ultraviolet (UV-C) radiation. Spectral photoconductivity measurements, performed in the 190 divided by 1100 nm wavelength range, returned an ultraviolet-to-visible (UV/Vis) rejection ratio of 6.8 x 10(3) under photovoltaic operating conditions, ensuring solar blindness and zero power consumption at the same time. When applying bias, UV/Vis rejection ratio reached excellent values (>10(4)) even at very low electric fields (0.01 V/mm), thanks to the excellent structural quality and the superior charge transport properties of the diamond bulk, as inferred from Raman analysis and spectral photoconductivity measurements. Mobility-lifetime (mt) product of the photogenerated carriers was indeed measured to be about 5 x 10(-3) cm(2)/V in the case of holes, which is the highest room-temperature mt value ever reported for CVD diamond, enabling a response speed in the nanosecond range even at zero-bias operating conditions. (C) 2021 Elsevier Ltd. All rights reserved.