A comparative study on comb electrodes devices made of MWPECVD diamond films grown on p-doped and intrinsic silicon substrate

Diamond is considered as a very promising material for the development of devices for radiation detection. Unlike other conventional photoconductive detectors diamond-based devices should provide high discrimination between UV and visible radiation. In this work we present the electro-optical properties of devices based on randomly oriented diamond films, synthesized in a microwave plasma enhanced chemical vapor deposition reactor. A comparative study on devices with coplanar interdigitated Cr/Au electrodes (with different interelectrode pitches) made of films grown simultaneously on intrinsic and p-doped silicon (100) substrates has been performed. The chemical–structural, morphological, electrical and optical properties of ROD films have been studied. In particular, the optical response has been measured in air using a Xe flash lamp coupled with an optical quartz fiber and a properly tailored front-end electronics based on a charge sensitive amplifier. Experimental results gave indications on how the device performances are dependent on the two types of employed substrates. ► Coplanar interdigitated electrodes design plays a strong role in electrical and photo electrical detectors parameters. ► We show a comparative study on comb electrodes obtained for devices based on randomly oriented diamond films. ► Randomly Oriented Diamond films have been grown on p type and i type silicon substrate with different electrode pattern geometry. ► Dark current, capacitance and photo detector efficiency for each device have been measured. ► The devices show good UV to visible signal ratio, especially for the films with an interelectrode gap comparable with the the film thickness.