Soft X-ray detection and photon counting spectroscopy with commercial 4H-SiC Schottky photodiodes

AbstractThe results of electrical characterisation and X-ray detection measurements of two different active area (0.06mm2 and 0.5mm2) commercial 4H-SiC Schottky photodiodes at room temperature are reported. The devices exhibited low dark currents (less than 10pA) even at a high electric field strengths (403kV/cm for 0.06mm2 diodes; 227kV/cm for 0.5mm2 diodes). The results of the X-ray measurements indicate that the diodes can be used as photon counting spectroscopic X-ray detectors with modest energy resolutions: FWHM at 5.9keV of 1.8keV and 3.3keV, for the 0.06mm2 and 0.5mm2 devices, respectively. Noise analysis of the photodiodes coupled to a custom low noise charge sensitive preamplifier is also presented