Solution processed highly sensitive visible-light photodetectors based on α-Fe2O3/p-Si heterojunctions

High-sensitive visible-light photodetectors based on α-Fe2O3 thin films on p-Si substrates with a responsivity as high as 2 × 103 A/W have been fabricated and characterized. The solution-processed devices exhibit a rapid rise/decay time (<1 ms) and a high ratio of photocurrent to dark current (∼1.3 × 104) under 12.5 mW/cm2 illumination at 403 nm. The superior performances can be attributed to the interface with a suitable energy band structure of the α-Fe2O3/p-Si heterojunction and the role of fast transport channel for photogenerated holes the p-Si substrates played. A stable, reversible, and rapid photoresponse at visible wavelengths, along with the simple, low-cost, and large-scale fabrication of the photodetectors, clearly demonstrates the possibility of industrial mass-production for commercial and military applications.