Related Experiment Video
Updated: May 3, 2026
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
14.7K
Space charge neutralization by electron-transparent suspended graphene
Siwapon Srisonphan1, Myungji Kim2, Hong Koo Kim3
11] Department of Electrical and Computer Engineering and Petersen Institute of NanoScience and Engineering, 1140 Benedum, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States of America [2] [3].
Scientific Reports
|January 21, 2014
Summary
Graphene anodes show high transparency to low-energy electrons. Induced hole charges in graphene neutralize electron space charge, significantly boosting electron emission beyond theoretical limits.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Graphene exhibits unique electronic properties due to its atomic structure.
- Understanding electron transport and charge interactions in graphene is crucial for advanced electronic devices.
Purpose of the Study:
- To measure the electron transparency of a suspended graphene anode.
- To investigate the hole charge induction response of graphene in a void channel.
- To analyze the impact of graphene on electron emission enhancement.
Main Methods:
- Fabrication of a suspended graphene anode over a void channel in a SiO2/Si substrate.
- Induction of a two-dimensional (2D) electron gas at the oxide interface.
- Measurement of electron transport and capture by the graphene anode.
- Analysis of space charge neutralization and emission enhancement.
Main Results:
- Graphene demonstrates high transparency (>~0.1%) to very low energy (<3 eV) electrons.
- Hole charges induced in graphene effectively neutralize electron space charge in the void channel.
- This charge compensation significantly enhances 2D electron gas emission from the cathode.
Conclusions:
- Suspended graphene anodes are effective for low-energy electron manipulation.
- Graphene's charge induction properties can overcome space-charge limitations in electron emission.
- This finding has implications for developing novel electron sources and vacuum nanoelectronics.
Related Concept Videos
01:30The Electrical Double Layer
241
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
241
01:26Charge on a Conductor
4.5K
An interesting property of a conductor in static equilibrium is that extra charges on the conductor end up on its outer surface, regardless of where they originate. Consider a hollow metallic conductor with a uniform surface charge density. Since the conductor itself is in electrostatic equilibrium, there should not be any electric field inside the conductor. Now, assume a Gaussian surface enclosing the hollow portion. Applying Gauss's law, the inner surface of the hollow conductor will not...
4.5K
02:42Formal Charges
32.2K
In some cases, there are seemingly more than one valid Lewis structures for molecules and polyatomic ions. The concept of formal charges can be used to help predict the most appropriate Lewis structure when more than one reasonable structure exists.
32.2K
01:15Charging Conductors By Induction
7.8K
The Earth is a good conductor of electricity, and it is so big that it can be considered an infinite source or sink of charges. It can easily exchange charges with any matter.
Generally, conductors like metals do not allow any excess charge to be present on them. Any excess charge added to metals easily flows away, for example, when a metal is placed on the Earth. This process is called earthing.
However, conductors can be charged by a process called induction. For example, consider charging a...
Generally, conductors like metals do not allow any excess charge to be present on them. Any excess charge added to metals easily flows away, for example, when a metal is placed on the Earth. This process is called earthing.
However, conductors can be charged by a process called induction. For example, consider charging a...
7.8K
01:30Electric Field of Two Equal and Opposite Charges
5.6K
Atoms generally contain the same number of positively and negatively charged particles, protons, and electrons. Hence, they are electrically neutral. However, the centers of the positive and negative charges do not always coincide. In such a scenario, the electric field of an atom may not be zero.
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
5.6K
01:23Electric Field of a Charged Disk
3.1K
The simplest case of a surface charge distribution is the uniformly charged disk. Calculating its electric field also helps us calculate the electric field of a large plane of charge.
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...
3.1K