Diamond electronics: Defect passivation for high performance photodetectoroperation

Deep UV, visible blind, photoconductive devices fabricated on polycrystalli ne CVD diamond using inter-digitated planar electrodes have shown promising characteristics. The 'as-fabricated' device performance is insufficient fo r many applications; a particularly demanding example is the monitoring of high power excimer lasers operating in the UV, which ideally require visibl e-blind, radiation hard fast UV detectors. However, post-growth treatments can strongly modify the performance level achieved. In this paper, we show that sequentially applied treatments can progressively change both the gain and speed of these devices. We have used charge sensitive deep level trans ient spectroscopy (Q-DLTS) to study the effect of these treatments on the d efect structure of CVD material. For the first time, we report the realisat ion of diamond photoconductive devices capable of operating at more than 1 MHz at 193 nm.