UV PHOTODETECTORS FROM THIN-FILM DIAMOND

Thin films of chemically vapour deposited diamond have been used to fa bricate photoconductive and photodiode structures for the detection of UV light. On free standing (80 mu m thick) material, a planar interdi gitated design with 20 mu m electrode spacing is found to offer greate r than five orders of magnitude in wavelength discrimination between d eep UV and visible light, with dark currents <0.1 nA, when a methane-a ir gas treatment is used. On silicon supported (6 mu m thick) films, a planar photodiode utilising gold Schottky and Ti-Ag-Au ohmic contacts , also offers a sharp cut-off in photoresponse in the deep UV with no measurable dark current; photoconductive devices fabricated on this ma terial do not show useful levels of performance.