Diamond microstrip detector for deep UV imaging

CVD diamond detectors with metal diamond metal (MDM) microstrip structures have been constructed and characterized for image sensor and large area applications. These sensors are suitable for UV and soft X-ray detection. The device photoelectrical characterization under deep UV (lambda=193 nm) laser pulses has been performed both on the nucleation and growth sides of a diamond slab, by varying bias voltage, contacts interspacing and light intensity. Such a characterization was also performed on a laser-smoothed part of the growth side. Reflecting the true electronic quality, largely different photocurrent peak shapes were detected on the untreated and laser-treated parts of the growth side, as well as on the nucleation side. Pulse amplitude and duration appear to decrease according to the different defect density value, which turns out to be larger on the laser-treated growth side of the diamond slab. Independent of pulsed illumination intensity, a linear photoresponse increase with the applied electric field is found in the range 10(1)-10(4) V/cm. Depending on the defect density value, the photocurrent versus pulse energy changes according to a different power law, the linear dependence extending into a wider pulse energy range when larger defect densities are involved. Such a characteristics is also a figure of the wide signal dynamics. The sensor uniformity has been also tested both on as grown and laser-treated surface, as well as on the nucleation side surface where a linear signal increase has been found by adding adjacent strips connected in parallel. These results suggest the suitability of the sensor for image acquisition. (c) 2005 Elsevier B.V. All rights reserved.