Temporal response of UV sensors made of highly oriented diamond films by 193 and 313 nm laser pulses

Abstract

Ultraviolet sensors were fabricated on a Si substrate using an undoped, highly oriented diamond film with Pt and Al interdigited electrodes with a gap length of 5, 10 and 15 μm. Transient voltage outputs due to photocurrent of the sensors under a bias voltage of 20, 40 and 80 V were measured by the pulsed irradiation of an ArF excimer laser (λ=193 nm, pulse width=5 ns) or a dye laser (λ=313 nm, pulse width=7 ns). It was found that the transient voltage output by the ArF laser irradiation on a sensor (Pt electrodes with a 15-μm gap) consisted of main and second peaks at 1.1 and 3.8 ns, respectively, when the bias voltage was 20 V. The FWHM was approximately 4 ns. The second peak was observed in the output signals of most sensors. On the other hand, the voltage output was two orders of magnitude weaker when the sensors were irradiated by the dye laser.