Optical control of internal electric fields in band-gap graded InGaN nanowires

TL;DR

This paper demonstrates that optically controlling internal electric fields in band-gap graded InGaN nanowires enables fast, tunable photocurrent responses, paving the way for innovative nanowire-based photodetectors.

Contribution

It introduces a method to control internal electric fields in graded InGaN nanowires using optical means, revealing a sign change in photocurrent and ultrafast response.

Findings

Sign change in photocurrent with photon flux

Photocurrent response as fast as 1.5 ps

Potential for new nanowire-based photodetectors

Abstract

InGaN nanowires are suitable building blocks for many future optoelectronic devices. We show that a linear grading of the indium content along the nanowire axis from GaN to InN introduces an internal electric field evoking a photocurrent. Consistent with quantitative band structure simulations we observe a sign change in the measured photocurrent as a function of photon flux. This negative differential photocurrent opens the path to a new type of nanowire-based photodetector. We demonstrate that the photocurrent response of the nanowires is as fast as 1.5 ps.