Low-cost photodetector architectures fabricated at room-temperature using nano-engineered silicon wafer and sol-gel...

In the last decades, significant research has been done on the nanocrystalline forms of titanium dioxide (TiO₂). Amorphous TiO₂ has not been studied intensively despite being significantly less expensive compared to crystalline TiO₂. This study reveals significant improvement in UV-VIS photodetection properties from heterostructures fabricated in ambient environment using n-type silicon nanowire arrays and amorphous TiO₂ sol-gel. Our ultra-low-cost UV-VIS photodetectors can cover a wide range of applications. We report fast rise/decay time constants of 0.23 ms/0.17 ms and high responsivity up-to 6.0 A/W in the UV and 25.0 A/W in the visible range under low (1 V) external bias. The large surface area due to the nanowire array architecture leads to 2 orders of magnitude enhancement in photo-response. Besides the final electrode deposition, the entire device fabrication is performed using low-cost, all solution-based methods in ambient conditions. These low-cost UV-Visible broadband photodetectors can potentially serve a wide range of applications.