Related Experiment Video
Updated: Jun 10, 2026

Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Silicon nitride gate dielectrics and band gap engineering in graphene layers
Wenjuan Zhu1, Deborah Neumayer, Vasili Perebeinos
1IBM Thomas J Watson Research Center, Yorktown Heights, New York 10598, USA. wenjuan@us.ibm.com
Abstract:
We show that silicon nitride can provide uniform coverage of graphene in field-effect transistors while preserving the channel mobility. This insulator allowed us to study the maximum channel resistance at the Dirac (neutrality) point as a function of the strength of a perpendicular electric field in top-gated devices with different numbers of graphene layers. Using a simple model to account for surface potential variations (electron-hole puddles) near the Dirac point we estimate the field-induced band gap or band overlap in the different layers.
Related Concept Videos
Semiconductors
Metals such as copper (Cu), zinc (Zn), or lead (Pb) have low resistivity and feature conduction bands that are either not fully occupied or overlap with the valence band, making a bandgap non-existent. This allows electrons in the highest energy levels of the valence band to easily transition to the conduction band upon gaining...
Fermi Level Dynamics
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Energy Bands in Solids
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
Band Theory
The energy difference between these bands is known as the band gap.
Conductor, Semiconductor,...
Fermi Level
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
Types of Semiconductors

