Quantum Transport Length Scales in Silicon-based Semiconducting Nanowires: Surface Roughness Effects

TL;DR

This study investigates quantum charge transport in silicon nanowires with surface roughness, analyzing how disorder affects conduction regimes, mobility, and localization, with results aligning with experimental data.

Contribution

It provides a detailed theoretical analysis of surface roughness effects on quantum transport in silicon nanowires using atomistic models and advanced computational methods.

Findings

Charge mobilities match experimental estimates.

Elastic mean free paths depend on surface roughness correlation length.

Limitations of Thouless relation are discussed.

Abstract

We report on a theoretical study of quantum charge transport in atomistic models of silicon nanowires with surface roughness-based disorder. Depending on the nanowires features (length, roughness profile) various conduction regimes are explored numerically by using efficient real space order N computational approaches of both Kubo-Greenwood and Landauer-Buttiker transport frameworks. Quantitative estimations of the elastic mean free paths, charge mobilities and localization lengths are performed as a function of the correlation length of the surface roughness disorder. The obtained values for charge mobilities well compare with the experimental estimates of the most performant undoped nanowires. Further the limitations of the Thouless relationship between the mean free path and the localization length are outlined.