Silver plasmonic density tuned polarity switching and anomalous behaviour of high performance self-powered \b{eta}-gallium oxide solar-blind photodetector

TL;DR

This study explores how silver nanoparticle density influences the polarity and behavior of ta-Ga2O3 solar-blind photodetectors, revealing tunable switching modes and anomalous effects driven by plasmonic interactions.

Contribution

It provides the first experimental demonstration of plasmonic tuning effects causing reverse and anomalous switching behaviors in ta-Ga2O3 photodetectors.

Findings

Polarity of photodetectors can be switched by Ag nanoparticle density.

High responsivity achieved with sparse Ag nanoparticle decoration.

Photocurrent behavior reverses with increasing nanoparticle density.

Abstract

Deep understanding of plasmonic nanoparticles (PNPs)-light interaction over semiconductors surface shows great promises in enhancing their optoelectronic devices efficiency beyond the conventional limit. However, PNP-light interaction critically decided by the distribution density of PNPs over the semiconductor surface which is not entirely understood. Here, a systematic study depicting how the interparticle gap between Silver (Ag) NPs influences the performance of the \b{eta}-Ga2O3 based solar-blind photodetector. Interestingly, a remarkable transition is observed, where the varied interparticle gap not only changes the polarity but also reverses the traditional photodetector behaviour. The positive transient response of bare \b{eta}-Ga2O3 photodetector with feeble DUV light switches its behaviour remarkably to 20 times enhance negative-photoresponse when decorated by sparsely-spaced Ag-PNPs with ultra-high responsivity of 107.47 A/W at moderate power and an incredible report-highest responsivity of 4.29 mA/W on single semiconducting \b{eta}-Ga2O3 layer at self-powered mode. Moreover, as the density of the Ag-PNPs was further increased, the photocurrent decreases with illumination which dynamically reverses the traditional photodetector to unnatural anomalous effect. In particular, our study represents the first demonstration of plasmonic tuning effect to two active dynamic switching modes; i.e. reverse switchable and anomalous behaviour, the fundamentals of which have not studied experimentally yet. Finally, we propose a unified well-explained model to rationalize all observed experimental trends while set-up fundamental basis for establishing potential applications.