Spectroscopic assessment of short-term nitric acid doping of epitaxial graphene

TL;DR

This study investigates the short-term and reversible hole doping effects of nitric acid on epitaxial graphene, using electrical and spectroscopic methods to understand desorption timescales and doping stability for device applications.

Contribution

It provides a detailed analysis of the transient nature of nitric acid-induced doping in epitaxial graphene using combined spectroscopic and electrical measurements.

Findings

Doping effects are reversible under vacuum conditions.

Desorption timescales are characterized by spectroscopic and electrical data.

Nitric acid doping can be a viable alternative to metallic gating.

Abstract

This work reports information on the transience of hole doping in epitaxial graphene devices when nitric acid is used as an adsorbent. Under vacuum conditions, desorption processes are monitored by electrical and spectroscopic means to extract the relevant timescales from the corresponding data. It is of vital importance to understand the reversible nature of hole doping because such device processing can be a suitable alternative to large-scale, metallic gating. Most measurements are performed post-exposure at room temperature, and, for some electrical transport measurements, at 1.5 K. Vacuum conditions are applied to many measurements to replicate the laboratory conditions under which devices using this doping method would be measured. The relevant timescales from transport measurements are compared with results from X-ray photoelecton spectroscopy and Fourier transform infrared spectroscopy measurements, with the latter performed at ambient conditions and accompanied by calculations of the spectra in the Reststrahlen band.