Solar-blind field-emission diamond ultraviolet detector

Abstract

We report our studies on the responsivity of sulfur-doped diamond films to ultraviolet radiation using two types of device configurations: the planar configuration with electrodes directly on the diamond surface, and the electron field emission configuration with a bias electrode suspended above the diamond surface. Diamond films of different grain sizes were employed: microcrystalline diamond, sub-microcrystalline diamond, and nanocrystalline diamond. The responsivity values of diamond films in the field emission configuration reached ∼10 mA/W at around 220 nm, which is ∼40% higher than that of the planar configuration. These responsivity values of diamond films are comparable to those of commercially available photodiodes in the wavelength range of 210-300 nm, but with the advantage of being solar blind. The responsivity data were correlated with the bandgap structure of sulfur-doped diamond.