Towards electron transport measurements in chemically modified graphene: The effect of a solvent

TL;DR

This study investigates how solvents used in chemical functionalization, specifically isopropanol, affect electron transport in graphene, revealing that solvents can significantly alter doping levels and mobility, complicating interpretation of chemical effects.

Contribution

The paper demonstrates that solvents used during chemical modification of graphene influence its electron transport properties, highlighting the need to consider solvent effects in such experiments.

Findings

Isopropanol reduces doping concentration and increases mobility.

Isopropanol alone increases dopant concentration and causes electron-hole asymmetry.

Solvent effects can mimic or obscure chemical functionalization impacts.

Abstract

Chemical functionalization of graphene modifies the local electron density of the carbon atoms and hence electron transport. Measuring these changes allows for a closer understanding of the chemical interaction and the influence of functionalization on the graphene lattice. However, not only chemistry, in this case diazonium chemistry, has an effect on the electron transport. Latter is also influenced by defects and dopants resulting from different processing steps. Here, we show that solvents used in the chemical reaction process change the transport properties. In more detail, the investigated combination of isopropanol and heating treatment reduces the doping concentration and significantly increases the mobility of graphene. Furthermore, the isopropanol treatment alone increases the concentration of dopants and introduces an asymmetry between electron and hole transport which might be difficult to distinguish from the effect of functionalization. The results shown in this work demand a closer look on the influence of solvents used for chemical modification in order to understand their influence.