Tailoring Ag nanoparticles via PLAL laser energy for high-performance GaN MSM UV photodetectors

Abstract

We explore the influence of laser pulse energy (100–1000 mJ) on the synthesis of silver nanoparticles (AgNPs) via pulse laser ablation in liquid (PLAL) and their integration into gallium nitride (GaN)-based ultraviolet (UV) photodetectors (PDs). Using 9 ns laser pulses at a wavelength of 1064 nm and a repetition rate of 10 Hz, we ablated a 99.99 % pure silver target submerged in ethanol, producing AgNPs that were subsequently deposited onto GaN-based UV PDs to enhance their performance. PDs were evaluated at wavelengths of 365 nm and 280 nm. The devices exhibited a remarkable responsivity of 374.73 A/W and a detectivity of 8.89 × 10¹² J in the deep UV range. Furthermore, the HR-TEM established a novel empirical correlation between the UV–Vis absorbance peak and nanoparticle size, which was also verified and explained by the simulation results. This correlation enables the rapid, non-destructive size estimation of AgNPs. These results offer critical insights into plasmonic enhancement mechanisms, contributing to advancing next-generation solar-blind UV PDs with superior sensitivity and wide-spectrum detection capabilities.