Low-field electron mobility of InSb nanowires: Numerical efforts to larger cross sections

TL;DR

This study uses a Boltzmann equation and k·p theory to analyze low-field electron mobility in large-diameter InSb nanowires, revealing how mobility varies with size and comparing it to silicon nanowires.

Contribution

It provides a detailed numerical analysis of electron mobility in large InSb nanowires considering multiple subbands and phonon modes, highlighting size-dependent behavior.

Findings

Mobility increases monotonically with nanowire diameter up to 51.84 nm.

Small InSb nanowires have similar mobility to Si nanowires of comparable size.

InSb nanowire mobility decreases faster than Si nanowires as size reduces.

Abstract

Within the framework of Boltzmann equation, we present a $\mathbf{k\cdot p}$ theory based study for the low-field mobilities of InSb nanowires (InSb NWs) with relatively large cross sectional sizes (with diameters up to 51.8 nm). For such type of large size nanowires, the intersubband electron-phonon scattering is of crucial importance to affect the scattering rate and then the mobility. In our simulation, the lowest 15 electron subbands and 50 transverse modes of phonons are carefully accounted for. We find that, up to the 51.84 nm diameter, the mobility monotonously increases with the diameter, not yet showing any saturated behavior. We also find that, while the bulk InSb mobility is considerably higher than the bulk Si, the small size (e.g. $\sim 3$ nm diameter) nanowires from both materials have similar magnitude of mobilities. This implies, importantly, that the mobility of the InSb NWs would decrease faster than the SiNWs as we reduce the cross sectional size of the nanowires.