Dynamic photoconductive gain effect in shallow-etched AlGaAs/GaAs quantum wires

TL;DR

This paper demonstrates a dynamic photoconductive gain effect in shallow-etched AlGaAs/GaAs quantum wires, revealing subband structures and charge dynamics through optical and electrical measurements.

Contribution

It introduces a novel method to resolve quantum wire subbands and analyze charge carrier dynamics using photoconductive gain effects in lithographically fabricated structures.

Findings

Quantum wires show maxima in photoresponse at subband energies.

Optically induced holes shift the quantum wire's chemical potential.

Recombination times limit the photoconductive gain dynamics.

Abstract

We report on a dynamic photoconductive gain effect in quantum wires which are lithographically fabricated in an AlGaAs/GaAs quantum well via a shallow-etch technique. The effect allows resolving the one-dimensional subbands of the quantum wires as maxima in the photoresponse across the quantum wires. We interpret the results by optically induced holes in the valence band of the quantum well which shift the chemical potential of the quantum wire. The non-linear current-voltage characteristics of the quantum wires also allow detecting the photoresponse effect of excess charge carriers in the conduction band of the quantum well. The dynamics of the photoconductive gain are limited by the recombination time of both electrons and holes.