Photocurrent and Photoconductance Properties of a GaAs Nanowire

TL;DR

This study investigates the optoelectronic properties of a p-doped GaAs nanowire, revealing polarization-sensitive photocurrent and photoconductance effects driven by surface charges and Schottky contacts.

Contribution

It demonstrates the fabrication and characterization of a GaAs nanowire photodetector with polarization-dependent responses, highlighting surface effects and contact influences.

Findings

Photocurrent generated at Schottky contacts.

Photoconductance explained by photogating effect.

Polarization sensitivity enables polarization-dependent detection.

Abstract

We report on photocurrent and photoconductance processes in a freely suspended p-doped single GaAs nanowire. The nanowires are grown by molecular beam epitaxy (MBE), and they are electrically contacted by a focused ion beam (FIB) deposition technique. The observed photocurrent is generated at the Schottky contacts between the nanowire and metal source-drain electrodes, while the observed photoconductance signal can be explained by a photogating effect induced by optically generated charge carriers located at the surface of the nanowire. Both optoelectronic effects are sensitive to the polarization of the exciting laser field, enabling polarization dependent photodetectors.