Diamond deep UV photodetectors: reducing charge decay times for 1-kHz operation

摘要

Diamond grown by chemical vapour deposition (CVD) methods is thought to be ideal for the fabrication of visible blind, fast deep UV photodetectors. However, careful device design and selection of high-quality CVD thin film diamond is, in itself, insufficient for the realisation of high performance devices. Post-growth device treatments are capable of transforming the optoelectronic properties of the material such that commercially interesting devices result. In the present study we have shown that sequentially applied methane-air treatments continue to modify both the gain level and speed of the device. Three such treatments give an optimal gain level, whilst more treatments than this lead to an improved turn-off speed. For the first time we have demonstrated the successful operation of a CVD diamond photoconductive device at at least 1 kHz at 193 nm, a frequency that is required for state-of-the-art excimer laser applications at this wavelength.