Position-sensitive detector (PSD) is an essential noncontact
optical
position sensor based on the lateral photovoltaic effect (LPE), which
plays a vital role in various applications. However, limited by the
absorption of substrate and rapid recombination of carriers, it remains
challenging to develop superior-performance PSDs. Here, we use Ag
nanoparticles (NPs) to boost the light-harvesting efficiency and ZnO
nanowires (NWs) to capture hot electrons and observe the plasmon-enhanced
LPE in this structure. Without any applied bias voltage, it shows
an excellent position sensitivity in a broad-band range of 405–980
nm with a maximum sensitivity of 252.6 mV/mm, which is about six times
larger than that in the ZnO NWs/Si (42.8 mV/mm) structure. Besides,
the LPE response is strongly dependent on the ZnO NW growth time and
Ag NP concentration. We elaborated the underlying mechanism by analyzing
hot electron generation and injection and the diffusion of charge
carriers under nonuniform light illumination. The excellent position
sensitivity performance can be attributed to the efficient transport
of hot electrons in the conductive network of the ZnO NW film. Our
findings further establish the potential of Ag-decorated ZnO NWs for
noncontact photoelectric sensing and provide insights into developing
high-sensitivity, low-cost, and self-powered PSDs.