In this work, SnO2 thin film was deposited on p-Si wafer substrates using the Hot Wall-Nebulizer Spray Pyrolysis technique with various precursor concentrations (PCs) of 0.015 M, 0.02 M, 0.025 M, and 0.05 M to form SnO₂/p-Si heterojunctions. The deposited SnO₂ matrix was characterized by XRD, FESEM and the Hall effect measurements to analyse their structural, morphological, and electrical properties, respectively. Different PCs resulted in modifications to the surface morphology and electrical characteristics of the films. The photoelectrical properties were investigated based on two distinct sections; various PCs and different electrode geometries (EGs), designated as ET-I, ET-II, and ET-III to fabricate Photodetectors (PDs). Silver contacts were placed in the configuration of Ag/SnO2/p-Si/Ag. The study was conducted under 365 nm UV LED illumination at a power density of 0.2 mW/cm2. Among all the EGs, the PD device of ET-III exhibited the excellent sensing capability. The fabricate PDs were analyzed through current–voltage (I-V) characteristics, light intensity versus photocurrent, and time-dependent transient photoresponse measurement. The ET-III device, fabricated using 0.05 M PC, demonstrated excellent performance: a sensitivity (Rλ) of 1750.1 mA/W, external quantum efficiency (EQE) of 598%, detectivity (D) of 4.0437 × 1011 Jones, and sensitivity (k) of 2263. Furthermore, all devices operated without an external power source (self-powered mode), making them ideal candidates for the development of efficient, low-power optoelectronic devices.
