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

A systematic investigation on the influence of metaldiamond 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 contacts maximizing the performance. To this purpose, a set of four nearly identical diamond samples has been grown using the microwave plasma enhanced CVD technique. Micro-Raman spectroscopy and photoluminescence have been utilized to assess their quality. Interdigitated planar contacts have been photolithographically deposited on each sample, using different layered metals. In particular, titaniumgold, chromiumgold, aluminumgold and gold were selected. The performance of these detectors has been investigated under steady photon irradiation in the 120300-nm wavelength range. The experimental results have been compared and discussed with respect to IV characteristics, dark current levels, signal-to-noise ratio, spectral response and time response.