Influence of metal-diamond interfaces on the response of UV photoconductors

A systematic investigation on the influence of metal-diamond interfaces on the electro-optical properties and on the UV response of CVD diamond photo- detectors was carried out in order to identify the optimal electric contact s maximizing the performance. To this purpose, a set of four nearly identic al diamond samples has been grown using the microwave plasma enhanced CVD t echnique. Micro-Raman spectroscopy and photoluminescence have been utilized to assess their quality. Interdigitated planar contacts have been photolit hographically deposited on each sample, using different layered metals. In particular, titanium-gold, chromium-gold, aluminum-gold and gold were selec ted. The performance of these detectors has been investigated under steady photon irradiation in the 120-300-nm wavelength range. The experimental res ults have been compared and discussed with respect to I-V characteristics, dark current levels, signal-to-noise ratio, spectral response and time resp onse. (C) 2001 Elsevier Science B.V. All rights reserved.