Photocurrent Polarity Switching and Enhanced Photoresponse in Silver Nanoparticles Decorated a-GaN-Based Photodetector

The photodetection properties of a-GaN nanorods-based photodetector and the effect of decorating silver nanoparticles are reported. For the pristine a-GaN detector, a surprising phenomenon of negative photoconductivity is observed, explained on the basis of defect states present in GaN nanorods. After the introduction of nanoparticles, the device exhibits reversal in the photocurrent polarity. The photoresponsivity reverses its sign from -0.12 A/W (bare a-GaN) to +6.75 A/W, with the introduction of nanoparticles (wavelength: 355 nm, 4.9 V bias). This current reversal and enhanced performance have been rationalized by considering passivation of surface defect states, resulting into significantly reduced dark current in the hybrid detector.

Automated summary

The photodetection properties of a-GaN nanorods-based photodetector and the effect of decorating silver nanoparticles are investigated. The original a-GaN detector exhibits negative photoconductivity, attributed to defect states in GaN nanorods. Introduction of nanoparticles reverses the photocurrent polarity, leading to a significant enhancement in the photoresponsivity due to the passivation of surface defect states and reduced dark current.