Analyzing capacitance-voltage measurements of vertical wrapped-gated nanowires

TL;DR

This paper presents a detailed analysis of capacitance-voltage measurements in vertical wrapped-gate InAs nanowires, revealing how doping, surface states, and charge coexistence influence electrical characteristics, with implications for nanowire material properties.

Contribution

It introduces a method using a Poisson-Schrödinger solver to extract doping density and analyze surface states from capacitance-voltage data of nanowires.

Findings

Doping density can be directly obtained from measurements.

Surface states significantly affect capacitance-voltage characteristics.

Material-dependent differences influence the capacitance beyond geometric limits.

Abstract

The capacitance of arrays of vertical wrapped-gate InAs nanowires are analyzed. With the help of a Poisson-Schr"odinger solver, information about the doping density can be obtained directly. Further features in the measured capacitance-voltage characteristics can be attributed to the presence of surface states as well as the coexistence of electrons and holes in the wire. For both scenarios, quantitative estimates are provided. It is furthermore shown that the difference between the actual capacitance and the geometrical limit is quite large, and depends strongly on the nanowire material.