Amplification of the photocurrent in SiO2(Co)/GaAs heterostructure induced by magnetic field in the avalanche regime

TL;DR

This paper reports a significant magnetic field-induced amplification of photocurrent in SiO2(Co)/GaAs heterostructures during avalanche conditions, driven by spin-dependent recombination processes.

Contribution

It demonstrates a novel magnetic field effect on photocurrent amplification in heterostructures involving cobalt nanoparticles and GaAs, with detailed explanation of the underlying spin-dependent mechanism.

Findings

Photocurrent amplification reaches 9.5 at 1.50 eV photon energy.

Magnetic field suppresses avalanche process but enhances photocurrent for energies above GaAs bandgap.

Amplification is due to spin-dependent recombination at impurity centers.

Abstract

Amplification of the photocurrent in heterostructures of silicon dioxide films containing cobalt nanoparticles grown on gallium arsenide SiO2(Co)/GaAs has been observed in magnetic field in the avalanche regime. While the avalanche process is suppressed by the magnetic field and the current decreases, for photon energy E greater than the GaAs bandgap energy the photocurrent significantly increases. The amplification reaches 9.5 for E = 1.50 eV. The effect of the photocurrent amplification is explained by the spin-dependent recombination process at deep impurity centers in GaAs.