Interface traps in graphene field effect devices: extraction methods and influence on characteristics

TL;DR

This paper investigates how near-interfacial oxide traps affect the electrical characteristics of graphene FETs, introduces extraction methods for trap density, and discusses how traps influence device behavior and measurement interpretation.

Contribution

It presents new methods for extracting interface trap density in graphene devices and analyzes how these traps impact device electrical characteristics and measurement results.

Findings

Interface traps significantly affect C-V and I-V characteristics.

Electron-electron interactions and puddles complicate trap density extraction.

Variations in resistivity peaks are explained by differing trap capacitances.

Abstract

We study impact of the near-interfacial oxide traps on the C-V and I-V characteristics of graphene gated structures. Methods of extraction of interface trap level density in graphene field effect devices from the capacitance-voltage measurements are described and discussed. It has been found that the effects of electron-electron or hole-hole interactions and electron-hole puddles can be mixed in C-V characteristics putting obstacles in the way of uniquely determined extraction of the interface trap density in graphene. Influence of the interface traps on DC and AC capacitance and conductance characteristics of graphene field-effect structures is described. It has been shown that variety of widths of resistivity peaks in various samples could be explained by different interface trap capacitance values.