Self-assembled Te nanowire thin film/silicon heterostructure for cost-effective and fast photoresponse in near-infrared photodetector

Due to its narrow bandgap and high carrier mobility, tellurium (Te) has tremendous potential for a variety of optoelectronic applications, especially in near-infrared (NIR) photodetection. However, the long-chain helical structure of Te poses a significant challenge in effective separating of photogenerated electrons and holes, thereby impacting the overall performance of Te-based photodetectors. To address this issue, we have developed a vertical heterostructure photodetector by combining a self-assembled hydrothermal p-type Te nanowire (NW) thin film with an n-type silicon substrate. This heterostructure facilitates efficient transfer and collection of photogenerated charges. The designed Te NW thin film/Si heterostructure photodetector not only exhibits self-power photodetection characteristics, but also demonstrates a responsivity of 0.12 A/W and detectivity of 3.5 × 1010 Jones under 808 nm illumination. Furthermore, the cost-effective photodetector displays fast photoresponse, with a rising time of 34.5 μs and a falling time of 32.8 μs, resulting in a corresponding 3 dB cutoff frequency of approximately 7 kHz. Consequently, the photodetector shows great potential as a cost-effective and high-speed alternative for developing Te-based NIR photoelectric devices.