Enhanced photoelectrochemical transient photoresponse properties of molybdenum oxide film deposited on black silicon

Nanostructured black silicon (b-Si) is widely deployed for different solar applications due to its novel light-harvesting characteristics, and large surface area-to-volume ratio. The present research work applies a novel approach via the chemical vapour deposition method to prepare molybdenum oxide (MoO3) film on a b-Si substrate for photoelectrochemical application. X-ray diffraction revealed α-MoO3 phase, with the MoO3/b-Si film exhibiting a relatively large crystallite size and improved crystalline quality. Optical reflectance measurements showed a relatively low reflectance and reduced optical bandgap energy for the MoO3/b-Si film. Chronoamperometric measurements showed an enhanced photocurrent density of 656.34 µA/cm2 at 1 V bias for the MoO3/b-Si photoanode measured in a 0.5 M H2SO4 solution. The enhanced photoelectrochemical activity could be attributed to an increase in light absorption, the relatively small bandgap energy, improved crystalline quality, and improved charge carrier separation and transfer at the interface.