Coexistence of quantum-confined Stark effect and localized states in an (In,Ga)N/GaN nanowire heterostructure

TL;DR

This study investigates (In,Ga)N/GaN nanowire heterostructures, revealing the coexistence of quantum-confined Stark effect and localized states through spectroscopic analysis and simulations, highlighting their impact on emission properties.

Contribution

It demonstrates the simultaneous presence of quantum-confined Stark effect and localized states in (In,Ga)N/GaN nanowires using combined experimental and simulation approaches.

Findings

Green luminescence is blueshifted with excitation density.

Quantum-confined Stark effect is confirmed by simulations.

Localized states produce sharp, non-shifting emission peaks.

Abstract

We analyze the emission of single GaN nanowires with (In,Ga)N insertions using both micro-photoluminescence and cathodoluminescence spectroscopy. The emission spectra are dominated by a green luminescence band that is strongly blueshifted with increasing excitation density. In conjunction with finite-element simulations of the structure to obtain the piezoelectric polarization, these results demonstrate that our (In,Ga)N/GaN nanowire heterostructures are subject to the quantum-confined Stark effect. Additional sharp peaks in the spectra, which do not shift with excitation density, are attributed to emission from localized states created by compositional fluctuations in the ternary (In,Ga)N alloy.