Timescales for Nitric Acid Desorption in Epitaxial Graphene Devices

TL;DR

This study investigates the transient hole doping dynamics in epitaxial graphene caused by nitric acid exposure, analyzing desorption timescales through electrical and optical measurements to inform device fabrication.

Contribution

It provides new insights into the desorption timescales of nitric acid-induced doping in epitaxial graphene, combining transport and Raman spectroscopy data.

Findings

Desorption timescales vary with temperature and measurement method.

Reversible hole doping can be achieved without gating.

Electrical and optical properties are affected by nitric acid exposure.

Abstract

This work reports the dynamics of transient hole doping in epitaxial graphene devices by using nitric acid as an adsorbent. The timescales associated with corresponding desorption processes are extracted from the data. The understanding of reversible hole doping without gating is of crucial importance to those fabricating devices with a particular functionality. Measurements of the electrical and optical properties of several devices post-exposure were performed with transport temperatures between 300 K and 1.5 K. Ambient conditions are applied to non-transport measurements to replicate the most likely laboratory conditions for handling devices using this doping method. The relevant timescales from transport measurements are compared with results from Raman spectroscopy measurements.