UV response of a transition metal oxide diode

New radiation detectors are being developed which are based upon transition metal oxide (TMO) semiconductive diodes. Transition metals are characterized by having a range of oxide states. Feasibility tests have identified that certain TMOs exhibit p-type semiconductor properties and others n-type, which when connected as a junction exhibit diode behavior. The TMOs are deposited on to a substrate via a flame spray process. The inert nature of the TMOs means that a wide variety of materials can provide a suitable substrate. Standard ceramic tiles and glass have routinely been used to date. Transition metal powders, of either p- or n-type, are injected into the flame by a controlled process and deposited in layers. The heat of the flame causes the transition metals to oxidize. The advantages of these detectors are that they can be deposited in very large areas on any shape substrate at a much lower cost than alternative semiconductor detectors. Although still in the development stage, these prototype detectors have demonstrated a useful response to x-ray in the keV and MeV range and protons. Recently preliminary tests were performed at UV wavelengths at the BaD ElPh beamline at Elettra. Results showed a linear response to UV flux across the 5 to 40 eV range, and excellent correlation with a silicon diode.