Heterotwin Zn3P2 superlattice nanowires: the role of indium insertion in the superlattice formation mechanism and their optical properties

TL;DR

This paper investigates the growth mechanism and optical properties of Zn3P2 nanowire superlattices formed via heterotwins, highlighting the role of indium insertion and surface energy reduction in superlattice formation.

Contribution

It reveals how periodic heterotwins driven by surface energy considerations lead to superlattice formation in Zn3P2 nanowires, with implications for nanowire-based optoelectronic devices.

Findings

Superlattices formed by heterotwins involve Zn-In exchange at boundaries.

Surface energy reduction drives zigzag superlattice formation.

Optical homogeneity maintained despite chemical variation.

Abstract

Zinc phosphide, Zn3P2, nanowires constitute prospective building blocks for next generation solar cells due to the combination of suitable optoelectronic properties and an abundance of the constituting elements in the Earths crust. The generation of periodic superstructures along the nanowire axis could provide an additional mechanism to tune their functional properties. Here we present the vapour-liquid-solid growth of zinc phosphide superlattices driven by periodic heterotwins. This uncommon planar defect involves the exchange of Zn by In at the twinning boundary. We find that the zigzag superlattice formation is driven by reduction of the total surface energy of the liquid droplet. The chemical variation across the heterotwin does not affect the homogeneity of the optical proerties, as measured by cathodoluminescence. The basic understanding provided here brings new perspectives on the use of II-V semiconductors in nanowire technology.