Optical properties of single ZnTe nanowires grown at low temperature

TL;DR

This study investigates the optical properties of low-temperature grown ZnTe nanowires, revealing strain-induced shifts in emission spectra and providing insights into their structural and optical characteristics.

Contribution

It presents a novel low-temperature growth method for ZnTe nanowires and analyzes their optical properties, highlighting strain effects on emission lines.

Findings

Narrow emission line with a 2-3 meV blue-shift compared to bulk ZnTe

Strain induced by a 5 nm oxide layer affects optical emission

Nanowires are zinc blende, tapered, and predominantly <111> oriented

Abstract

Optically active gold-catalyzed ZnTe nanowires have been grown by molecular beam epitaxy, on a ZnTe(111) buffer layer, at low temperature 350\degree under Te rich conditions, and at ultra-low density (from 1 to 5 nanowires per micrometer^{2}. The crystalline structure is zinc blende as identified by transmission electron microscopy. All nanowires are tapered and the majority of them are <111> oriented. Low temperature micro-photoluminescence and cathodoluminescence experiments have been performed on single nanowires. We observe a narrow emission line with a blue-shift of 2 or 3 meV with respect to the exciton energy in bulk ZnTe. This shift is attributed to the strain induced by a 5 nm-thick oxide layer covering the nanowires, and this assumption is supported by a quantitative estimation of the strain in the nanowires.