Negative photoconductance in SiO2(Co)/GaAs heterostructure in the avalanche regime

TL;DR

This study reports negative photoconductance in SiO2(Co)/GaAs heterostructures during avalanche conditions, where sub-bandgap light reduces current by trapping holes and suppressing avalanche feedback.

Contribution

It demonstrates the occurrence of negative photoconductance in SiO2(Co)/GaAs heterostructures under avalanche regime, revealing a new photoconductive behavior related to defect trapping.

Findings

Negative photoconductance observed under avalanche conditions.

Sub-bandgap light creates trapped holes that suppress avalanche feedback.

Current reduction correlates with defect-related hole trapping.

Abstract

In the avalanche regime we observed the negative photoconductance of heterostructures of silicon dioxide films containing cobalt nanoparticles grown on gallium arsenide, SiO2(Co)/GaAs. Light irradiation with the photon energy less than the bandgap energy of the GaAs creates holes trapped on defects within the GaAs bandgap, suppresses the avalanche feedback and causes a reduction of the current flowing in the SiO2(Co)/GaAs.