Localized Surface Plasmon Induced Position-Sensitive Photodetection in Silicon-Nanowire-Modified Ag/Si

Surface plasmon-based approaches are widely applied to improve the efficiency of photoelectric devices such as photosensors and photocells. In order to promote the light absorption and electron-hole pair generation in devices, metallodielectric nanostructures are used to boost the growth of surface plasmons. Here, silicon nanowires (SiNWs) are used to modify a metal-semiconductor structure; thus, Ag/SiNWs/Si is manufactured. In this system, a large increased lateral photovoltaic effect (LPE) is detected with a maximum positional sensitivity of 65.35 mV mm^-1 , which is ≈53-fold and 1000-fold compared to the conventional Ag/Si (1.24 mV mm^-1 ) and SiNWs/Si (0.06 mV mm^-1 ), respectively. It is demonstrated that localized surface plasmons (LSPs) contribute a lot to the increment of LPE. Furthermore, through the surface-enhanced Raman scattering spectra of rhodamine-6G and finite-difference time-domain simulation, it is illustrated that silver-coated SiNWs support strong LSPs. The results propose an enhancement mechanism based on LSPs to facilitate the photoelectric conversion in LPE and offer an effective way to improve the sensitivity of photodetectors.