Optimizing UV detection properties of n-ZnO nanowire/p-Si heterojunction photodetectors by using a porous substrate
In this work, the effect of porous silicon substrates with various structures on response in ultraviolet range of a zinc oxide nanowire based heterojunction ultraviolet detectors was studied. This was realized through modifications made in bandgap of silicon as a result of porosification for the purpose of increasing the sensitivity and selectivity. Different porous substrates were prepared by electrochemical anodic etching process at different anodization times, current densities and acid concentration which is considered an easy and cost-effective fabrication process that makes the proposed heterojunction a suitable choice for ultraviolet sensing applications. The electrical and optical properties of the prepared samples were measured and the sample with highest porosity exhibits the most selective response with the highest sensitivity (\(2\times 10^{4}\) at \(-\)3.4V) and the lowest dark current (\(1.2\times 10^{-8}\) A at \(-\)3.4V) among all samples, although the sample with crystalline silicon substrate shows the highest responsivity (1,109A/W at 356nm).
heterojunction porous silicon uv detector zno nanowire