Evidence for semiconducting behavior with a narrow band gap of Bernal graphite

TL;DR

This study investigates the resistivity of highly oriented graphite samples, revealing that ideal Bernal-stacked graphite behaves as a narrow-gap semiconductor with an energy gap around 40 meV, influenced by both semiconducting layers and internal interfaces.

Contribution

The paper provides experimental evidence that Bernal graphite is a narrow-gap semiconductor, clarifying its electronic behavior and the role of internal interfaces.

Findings

Graphite exhibits semiconducting behavior with a narrow energy gap of ~40 meV.

Resistivity results can be explained by contributions from semiconducting layers and metallic interfaces.

Ideal Bernal graphite is characterized as a narrow-gap semiconductor.

Abstract

We have studied the resistivity of a large number of highly oriented graphite samples with areas ranging from several mm$^2$ to a few $\mu$m$^2$ and thickness from $\sim 10 $nm to several tens of micrometers. The measured resistance can be explained by the parallel contribution of semiconducting graphene layers with low carrier density $< 10^9$ cm$^{-2}$ and the one from metallic-like internal interfaces. The results indicate that ideal graphite with Bernal stacking structure is a narrow-gap semiconductor with an energy gap $E_g \sim 40 $meV.