Influence of Te-doping on self-catalyzed VS InAs nanowires

TL;DR

This study investigates how tellurium doping influences the morphology, crystal structure, and electrical conductivity of self-catalyzed InAs nanowires grown on silicon substrates via molecular beam epitaxy.

Contribution

It provides new insights into the effects of Te-doping on nanowire properties and highlights the role of growth conditions such as arsenic pressure in these effects.

Findings

Te-doping decreases nanowire length and increases diameter.

Te-doping enhances zinc blende crystal structure ratio.

Increased Te-doping improves electrical conductivity.

Abstract

We report on growth of Te-doped self-catalyzed InAs nanowires by molecular beam epitaxy on silicon (111) substrates. Changes in the wire morphology, i.e. a decrease in length and an increase in diameter have been observed with rising doping level. Crystal structure analysis based on transmission electron microscopy as well as X-ray diffraction reveals an enhancement of the zinc blende/(wurtzite+zinc blende) segment ratio if Te is provided during the growth process. Furthermore, electrical two-point measurements show that increased Te-doping causes a gain in conductivity. Two comparable growth series, differing only in As-partial pressure by about $1 \times 10^{-5}$ while keeping all other parameters constant, were analyzed for different Te-doping levels. Their comparison suggests that the crystal structure is stronger affected and the conductivity gain is more distinct for wires grown at a comparably higher As-partial pressure.