Photoconductive properties of single-crystal CVD diamond

A single-crystal homoepitaxial CVD diamond film, grown on a Ib-type diamond substrate, was analysed using optical and electro-optical measurements. The type and the distribution of its crystalline defects are discussed in connection with its photoconductive response to deep UV light. A similar device based on a high quality polycrystalline CVD diamond was also analysed using the same techniques in order to compare the results. Raman spectroscopy and photoluminescence (PL) have been used to assess the crystalline quality and to study the distribution of defects in the films, respectively. The results of the electro-optical measurements show that the single crystal diamond has very high responsivity and signal-to-noise ratio. Hence, the role of defects on the detection performance is discussed.