Intrinsic Response of Graphene Vapor Sensors

TL;DR

This paper investigates how contamination affects graphene vapor sensors, showing that cleaning the surface reveals the material's true sensing capabilities and the contamination's dual role in both degrading and enhancing sensor response.

Contribution

It introduces a cleaning process that removes resist residue, enabling measurement of graphene's intrinsic sensor response, and clarifies contamination's impact on sensor performance.

Findings

Contamination degrades electronic properties of graphene.

Cleaning restores intrinsic sensor responses.

Contamination enhances sensor response by concentrating analytes.

Abstract

Graphene is a purely two-dimensional material that has extremely favorable chemical sensor properties. It is known, however, that conventional nanolithographic processing typically leaves a resist residue on the graphene surface, whose impact on the sensor characteristics of the system has not yet been determined. Here we show that the contamination layer both degrades the electronic properties of the graphene and masks graphene s intrinsic sensor responses. The contamination layer chemically dopes the graphene, enhances carrier scattering, and acts as an absorbent layer that concentrates analyte molecules at the graphene surface, thereby enhancing the sensor response. We demonstrate a cleaning process that verifiably removes the contamination on the device structure and allows the intrinsic chemical responses of graphene to be measured.