Carrier statistics and quantum capacitance effects on mobility extraction in two-dimensional crystal semiconductor field-effect transistors

TL;DR

This paper investigates how high density of states and quantum capacitance in 2D semiconductor transistors affect carrier density and mobility measurements, proposing a new extraction method to improve accuracy.

Contribution

It introduces a novel approach for accurately extracting carrier densities and mobilities in 2D semiconductor transistors considering quantum effects.

Findings

High band-edge density of states impacts carrier statistics.

Traditional mobility extraction methods may be inaccurate for 2D materials.

A new method improves the accuracy of mobility and carrier density measurements.

Abstract

In this work, the consequence of the high band-edge density of states on the carrier statistics and quantum capacitance in transition metal dichalcogenide two-dimensional semiconductor devices is explored. The study questions the validity of commonly used expressions for extracting carrier densities and field-effect mobilities from the transfer characteristics of transistors with such channel materials. By comparison to experimental data, a new method for the accurate extraction of carrier densities and mobilities is outlined. The work thus highlights a fundamental difference between these materials and traditional semiconductors that must be considered in future experimental measurements.