Study of patterned GaAsSbN nanowires using sigmoidal model

Sean Johnson,Hemali Rathnayake,Klinton Davis,Hirandeep Kuchoor,Michael Lowe,Rabin Pokharel,Surya Nalamati,Shanthi Iyer

doi:10.1038/s41598-021-83973-9

Abstract

This study presents the first report on patterned nanowires (NWs) of dilute nitride GaAsSbN on p-Si (111) substrates by self-catalyzed plasma-assisted molecular beam epitaxy. Patterned NW array with GaAsSbN of Sb composition of 3% as a stem provided the best yield of vertical NWs. Large bandgap tuning of ~ 75 meV, as ascertained from 4 K photoluminescence (PL), over a pitch length variation of 200–1200 nm has been demonstrated. Pitch-dependent axial and radial growth rates show a logistic sigmoidal growth trend different from those commonly observed in other patterned non-nitride III–V NWs. The sigmoidal fitting provides further insight into the PL spectral shift arising from differences in Sb and N incorporation from pitch induced variation in secondary fluxes. Results indicate that sigmoidal fitting can be a potent tool for designing patterned NW arrays of optimal pitch length for dilute nitrides and other highly mismatched alloys and heterostructures.

Highlights

Nanowires (NWs), due to their unique properties arising from one-dimensional (1D) architecture, demonstrate excellent enhancement of light confinement, photosensitivity, and optical absorption for optoelectronic applications such as photodetectors, optical switches, optical interconnects, and solar cells[1,2,3,4,5,6,7]
NWs grown via selective area growth (SAG) techniques, which is a hybrid of top-down and bottom-up nanofabrication methods, further enhance these properties by patterning the substrate to precisely position nucleation sites for self-assisted vapor–liquid-solid (SA-VLS) growth of vertical NWs
The NW growth consists of a GaAs stem, GaAsSb stem, and the GaAsSbN NW

Summary

Introduction

Nanowires (NWs), due to their unique properties arising from one-dimensional (1D) architecture, demonstrate excellent enhancement of light confinement, photosensitivity, and optical absorption for optoelectronic applications such as photodetectors, optical switches, optical interconnects, and solar cells[1,2,3,4,5,6,7]. This maximum contribution is predicted to occur at lower pitch lengths and is consistent with results observed in non-nitride patterned GaAs/ GaAsSb NWs. this trend is not observed within the results obtained for patterned GaAsSbN NWs. It is surmised that the changes in the fluxes at each pitch produce average growth rates that follow a sigmoidal trend, which can be used to describe systems in where there is a transition from one steady-state to a nother[46,47,48].

Results

Conclusion