Using TiO 2 to capture hot electrons for self-powered position-sensitive photodetection

• Published in: Optics letters Vol. 49; no. 19; p. 5367
• Main Authors: Zheng, Diyuan, Deng, Wenhao, Duan, Zhiyong, Dong, Lin, Dong, Xinyuan
• Format: Journal Article
• Language: English
• Published: United States 01.10.2024
• ISSN: 1539-4794
• DOI: 10.1364/OL.538571

As environmental issues arise, the demand for self-powered position-sensitive detectors (PSDs) is increasing because of their advantages in miniaturization and low power consumption. Finding higher efficiency schemes for energy conversion is paramount for realizing high-performance self-powered PSDs. Here, a surface plasmon-based approach was used to improve the energy conversion efficiency, and a plasmon-enhanced lateral photovoltaic effect (LPE) was observed in PSD with TiO /Au nanorods (NRs)/Si structure. The Au NRs convert absorbed light energy into electricity by generating hot electrons, which are efficiently captured by the TiO layer, and the PSD is capable of generating position sensitivity as high as 251.75 mV/mm when illuminated by a 780 nm laser without any external power supply, i.e. about five times higher than similar sensors in previous studies. In addition, the position sensitivity can be tailored by the thickness of TiO films. The enhancement mechanism is investigated by a localized surface plasmon (LSP)-driven carrier diffusion model. These findings reveal an important strategy for high sensitivity and low energy cost PSDs while opening up new avenues for energy harvesting self-powered position sensors.