Large excitonic binding energy in GaN based superluminescent light emitting diode on naturally survived sub-10 nm lateral nanowires

TL;DR

This paper reports the formation of sub-10 nm GaN nanowires via natural selection during wet etching, leading to enhanced excitonic emission and superluminescent LEDs with high efficiency and stability.

Contribution

It introduces a novel natural etching method for creating defect-free, ultra-thin GaN nanowires with high exciton binding energy for improved optoelectronic devices.

Findings

Nanowires of sub-10 nm diameter were naturally formed during wet etching.

The nanowires exhibit large exciton binding energies (~45 meV).

The LEDs show superluminescent behavior with no efficiency roll-off at high current densities.

Abstract

We demonstrate a novel method for nanowire formation by natural selection during wet chemical etching in boiling Phosphoric acid. It is observed that wire lateral dimensions of sub-10 nm and lengths of 700 nm or more have been naturally formed during the wet etching. The dimension variation is controlled through etching times wherein the underlying cause is the merging of the nearby crystallographic hexagonal etch pits. The emission processes involving excitons are found to be efficient and lead to enhanced emission characteristics. The exciton binding energy is augmented by using quantum confinement whereby enforcing greater overlap of the electron-hole wave-function. The surviving nanowires are nearly defect-free, have large exciton binding energies of around 45 meV and a small temperature variation of the output electroluminescent light. We have observed superluminescent behaviour of the LEDs formed on these nanowires. There is no observable efficiency roll off till current densities of 400 A/cm2. The present work thus provides an innovative and cost effective manner of device fabrication on the formed nanowires and proves the immediate performance enhancement achievable.