THIN-FILM DIAMOND PHOTODIODE FOR ULTRAVIOLET-LIGHT DETECTION

A photodiode has been constructed from Lightly boron doped, Si support ed, thin film chemically vapor deposited (CVD) diamond which shows ove r five orders of magnitude discrimination between deep UV (<220 nm) an d visible light. A thin (10 nm) gold Schottky barrier with an associat ed Ti-Ag-Au ohmic contact was used to create a rectifying device with low (<2 pA) dark currents when reversed biased. This structure showed a sharp cut off in photoresponse at 220 nm, the band gap energy of dia mond. Conversely, a photoconductive device fabricated from similar (no minally undoped) material gave a broader UV photoresponse and displaye d high dark currents; the superior performance of the diode structure on fine grain material is discussed. (C) 1996 American Institute of Ph ysics.