Blue shift of yellow luminescence band in self-ion-implanted n-GaN nanowire

TL;DR

This study investigates the blueshift of yellow luminescence in self-ion-implanted n-GaN nanowires, revealing defect-related emission changes and their recovery through annealing.

Contribution

It demonstrates how ion implantation induces defect-related luminescence shifts and how annealing can restore the original emission properties in n-GaN nanowires.

Findings

Yellow luminescence band blueshifts with increased ion fluence.

Donor-acceptor pair model explains the shift involving nitrogen vacancies.

Annealing restores the luminescence peak position.

Abstract

Optical photoluminescence studies are performed in self-ion (Ga+)-implanted nominally doped n-GaN nanowires. A 50-keV Ga+ focused ion beam (FIB) in the fluence range of 1x1014 -2x10^16 ions cm^-2 is used for the irradiation process. A blueshift is observed for the yellow luminescence (YL) band with increasing fluence. Donor-acceptor pair (DAP) model with emission involving shallow donor introduced by point-defect clusters related to nitrogen vacancies and probable deep acceptor created by gallium interstitial clusters is made responsible for the shift. High temperature annealing in nitrogen ambient restores the peak position of YL band by removing nitrogen vacancies.