Characterization of photoconductive diamond detectors as a candidate of FUV/VUV transfer standard detectors

Abstract

Photoconductive diamond detectors consisting of highly oriented film were characterized in temporal response, spectral responsivity and its spatial uniformity as a candidate for FUV/VUV transfer standard detectors. The results showed that the diamond detectors have superior stability under 172 nm irradiation but need to be improved for better carrier collection efficiency, uniformity and temporal response. The slow temporal response and the non-zero spectral responsivity below the band-gap photon energy strongly suggest the presence of long lifetime carrier traps. A strong correlation was found between the average facet size observed by SEM and the spatial responsivity, suggesting that defects in the grain boundaries are the origin of the traps. The spectral responsivity measurements revealed that the photoemission current contribution to the total output current is almost dominant in the wavelength range from 40 nm to 60 nm.