Sulfur and few-layer graphene interaction under thermal treatments

TL;DR

This study investigates how sulfur interacts with multilayer graphene under thermal treatments, revealing altered thermal behavior, covalent bonding, doping effects, and proposing a new 2D sulfur structure based on experimental and theoretical analysis.

Contribution

It demonstrates sulfur-graphene covalent bonding and doping at high temperatures, and proposes a novel 2D sulfur structure through combined experimental and computational methods.

Findings

Sulfur exhibits different thermal behavior when confined between graphene layers.

Covalent sulfur-graphene bonds and p-type doping were achieved at 500°C.

A new bidimensional sulfur structure is hypothesized based on first-principles calculations.

Abstract

In this work we study sulfur confined between two multilayer graphene films under thermal treatments by means of electrical and Raman spectroscopy characterization. We found some similarities between the electrical behavior and differential scanning calorimetry of sulfur immersed into nanoporous anodic alumina template during sulfur phase transitions, this suggests that sulfur has a different thermal behavior when it is in confining conditions compared to the free state. In addition, multilayer graphene was exposed to sulfur vapors at 500 {\deg}C to induce chemical reaction. This method effectively produced covalent bonding between sulfur and multilayer graphene and a p-type doping of about 2x10^13 cm^-2 in charge concentration. Finally, based on first principle calculations we speculate on the existence of a new bidimensional structure of sulfur.