Photoconductivity of highly oriented and randomly oriented diamond films for the detection of fast UV laser pulses

Diamond is a wide band-gap material that, depending on purity may exhibit a short carrier lifetime and because of its strong lattice bonding it generally exhibits a high damage threshold. For these reasons it is considered to be suitable for fast and solar blind UV detectors. The use of highly oriented diamond (HOD) films should be advantageous over randomly oriented diamond (ROD) films because of the lower grain boundary density that should lead to an increase in the carrier mobility. In the present study, we compare the photoresponse of UV detectors made of HOD and ROD films using an ArF excimer pulsed laser and we measure the UV-visible discrimination factor of both types of diamond films using a tunable laser. Because the ROD film available for this study was considerably thinner than the respective HOD film, some of the conclusions of this paper are specific to this particular thickness ratio. (C) 2002 Elsevier Science B.V. All rights reserved.