Understanding the role of facets and twin defects in the optical performance of GaAs nanowires for laser applications

Zahra Azimi, Nikita Gagrani, Jiangtao Qu, Olivier L.C. Lem, Sudha Mokkapati, Julie M. Cairney, Rongkun Zheng, Hark Hoe Tan, Chennupati Jagadish, Jennifer Wong-Leung

Research output: Contribution to journalArticleResearchpeer-review

12 Citations (Scopus)

Abstract

GaAs nanowires are regarded as promising building blocks of future optoelectronic devices. Despite progress, the growth of high optical quality GaAs nanowires is a standing challenge. Understanding the role of twin defects and nanowire facets on the optical emission and minority carrier lifetime of GaAs nanowires is key for the engineering of their optoelectronic properties. Here, we present new insights into the microstructural parameters controlling the optical properties of GaAs nanowires, grown via selective-area metal-organic vapor-phase epitaxy. We observe that these GaAs nanowires have a twinned zinc blende crystal structure with taper-free {110} side facets that result in an ultra-low surface recombination velocity of 3.5 × 104 cm s-1. This is an order of magnitude lower than that reported for defect-free GaAs nanowires grown by the vapor-liquid-solid technique. Using time-resolved photoluminescence and cathodoluminescence measurements, we untangle the local correlation between structural and optical properties demonstrating the superior role of the side facets in determining recombination rates over that played by twin defects. The low surface recombination velocity of these taper-free {110} side facets enable us to demonstrate, for the first time, low-temperature lasing from bare (unpassivated) GaAs nanowires, and also efficient room-temperature lasing after passivation with an AlGaAs shell.

Original languageEnglish
Pages (from-to)559-567
Number of pages9
JournalNanoscale Horizons
Volume6
Issue number7
DOIs
Publication statusPublished - Jul 2021

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