Nanowire growth and sublimation: CdTe quantum dots in ZnTe nanowires

TL;DR

This paper investigates the effects of sublimation and evaporation during CdTe-ZnTe nanowire growth, demonstrating control over quantum dot formation, interface sharpness, and shape, with implications for nanowire device fabrication.

Contribution

It provides new insights into controlling quantum dot incorporation and interface quality in nanowires through temperature and growth condition management.

Findings

Controlled growth yields sharp quantum dot interfaces.

High temperature reduces Cd incorporation and adatom density.

Uncapped CdTe segments dissolve, forming bulb-like shapes.

Abstract

The role of the sublimation of the compound and of the evaporation of the constituents from the gold nanoparticle during the growth of semiconductor nanowires is exemplified with CdTe-ZnTe heterostructures. Operating close to the upper temperature limit strongly reduces the amount of Cd present in the gold nanoparticle and the density of adatoms on the nanowire sidewalls. As a result, the growth rate is small and strongly temperature dependent, but a good control of the growth conditions allows the incorporation of quantum dots in nanowires with sharp interfaces and adjustable shape, and it minimizes the radial growth and the subsequent formation of additional CdTe clusters on the nanowire sidewalls, as confirmed by photoluminescence. Uncapped CdTe segments dissolve into the gold nanoparticle when interrupting the flux, giving rise to a bulb-like (pendant-droplet) shape attributed to the Kirkendall effect.