Phase Diagram for Twinning Superlattice Te-Doped GaAs Nanowires

Twinning superlattices (TSLs) are a growing class of semiconductor structures proposed as a means of phonon and optical engineering in nanowires (NWs). In this work, we examine TSL formation in Te-doped GaAs NWs grown by a self-assisted vapor-liquid-solid mechanism (with a Ga droplet as the seed particle), using selective-area molecular beam epitaxy. In these NWs, the TSL structure is comprised of alternating zincblende twins, whose formation is promoted by the introduction of Te dopants. Using transmission electron microscopy, we investigated the crystal structure of NWs across various growth conditions (V/III flux ratio, temperature), finding periodic TSLs only at the low V/III flux ratio of 0.5 and intermediate growth temperatures of 492 to 537 degrees C. These results are explained by a kinetic growth model based on the diffusion flux feeding the Ga droplet.

Automated summary

Transmission electron microscopy was used to investigate the formation of TSLs in Te-doped GaAs nanowires grown by selective-area molecular beam epitaxy, revealing periodic TSLs only at low V/III flux ratio and intermediate growth temperatures. These results were explained by a kinetic growth model based on diffusion flux feeding the Ga droplet.