Mechanical behavior of InP twinning superlattice nanowires

TL;DR

This study investigates the mechanical properties and fracture mechanisms of InP twinning superlattice nanowires, revealing brittle failure without inelastic deformation, supported by experimental tensile tests and molecular dynamics simulations.

Contribution

It provides the first detailed analysis of the tensile behavior and fracture mechanisms of InP TSL nanowires, combining experimental and simulation approaches.

Findings

Brittle fracture occurs along twin boundaries.

Elastic modulus, failure strain, and tensile strength are quantified.

Fracture propagates via crack surface propagation along twin boundaries.

Abstract

Taper-free InP twinning superlattice (TSL) nanowires with an average twin spacing of ~ 13 nm were grown along the zinc-blende close-packed [111] direction using metalorganic vapor phase epitaxy. The mechanical properties and fracture mechanisms of individual InP TSL nanowires in tension were ascertained by means of in situ uniaxial tensile tests in a transmission electron microscope. The elastic modulus, failure strain and tensile strength along the [111] direction were determined. No evidence of inelastic deformation mechanisms was found before fracture, which took place in a brittle manner along the twin boundary. The experimental results were supported by molecular dynamics simulations of the tensile deformation of the nanowires that also showed that the fracture of twinned nanowires occurred in the absence of inelastic deformation mechanisms by the propagation of a crack from the nanowire surface along the twin boundary.