Related Experiment Video
Updated: May 13, 2026
10:53
Scanning-probe Single-electron Capacitance Spectroscopy
Published on: July 30, 2013
Arbitrarily Large Area Graphene Suspension with Ultralow Standoff for Varying Capacitance Applications
Tamzeed B Amin1, Md R Kabir2, Syed M Rahman2
1Department of Physics, University of Arkansas, Fayetteville, AR 72701, USA.
Nanomaterials (Basel, Switzerland)
|May 12, 2026
Summary
Researchers developed a scalable method to create thousands of freestanding graphene variable capacitors on silicon wafers. This process enables voltage-controlled capacitance for advanced electronic applications.
Area of Science:
- Materials Science
- Electrical Engineering
- Nanotechnology
Background:
- Freestanding graphene offers unique mechanical and electrical properties.
- Graphene's flexibility allows for voltage-controlled capacitor (varactor) applications.
Purpose of the Study:
- To present a detailed, scalable fabrication process for graphene-based variable capacitor devices.
- To enable mass production of individually accessible freestanding graphene varactors.
Main Methods:
- Utilized standard semiconductor fabrication techniques on 100 mm silicon wafers.
- Key steps include metal deposition, oxide etching, graphene transfer, oxygen plasma patterning, critical point drying, and wire bonding.
- Characterization involved optical microscopy, atomic force microscopy, and electrical measurements.
Main Results:
- Successfully fabricated thousands of individually accessible freestanding graphene variable capacitors.
- Confirmed device design specifications through microscopy.
- Demonstrated successful graphene suspension and voltage-controlled capacitance via electrical characterization.
- The process is compatible with both pure multilayer graphene and graphene with PMMA.
Conclusions:
- The presented fabrication process is detailed, scalable, and effective for producing graphene variable capacitors.
- The method successfully suspends graphene, enabling varactor functionality.
- This work paves the way for the integration of graphene-based tunable capacitors in electronic devices.
Related Concept Videos
01:19Equivalent Capacitance
Multiple capacitors can be connected in a circuit in series or parallel configuration. When the capacitor combination is connected to a battery, the potential drop across each capacitor and the magnitude of charge stored in the individual capacitor depends on the type of the connection. The capacitor combination is replaced by a single equivalent capacitor that stores the same amount of charge as the combination for a given potential difference.
The following strategies are adopted to calculate...
The following strategies are adopted to calculate...
01:19Equivalent Capacitance
From the study of resistive circuits, it is understood that employing a series-parallel combination serves as an effective strategy for simplifying circuits. Capacitors can be arranged within a circuit in one of two ways: a series configuration or a parallel configuration. The way these capacitors are connected to a battery will influence both the potential drop across each individual capacitor and the size of the charge that each capacitor can store. This is determined by the specific type of...
01:25MOS Capacitor
A Metal-Oxide-Semiconductor (MOS) capacitor is a fundamental structure used extensively in semiconductor device technology, particularly in the fabrication of integrated circuits and MOSFETs (metal-oxide-semiconductor field-effect transistors). The MOS capacitor consists of three layers: a metal gate, a dielectric oxide, and a semiconductor substrate.
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
01:26Spherical and Cylindrical Capacitor
A spherical capacitor consists of two concentric conducting spherical shells of radii R1 (inner shell) and R2 (outer shell). The shells have equal and opposite charges of +Q and −Q, respectively. For an isolated conducting spherical capacitor, the radius of the outer shell can be considered to be infinite.
Conventionally, considering the symmetry, the electric field between the concentric shells of a spherical capacitor is directed radially outward. The magnitude of the field, calculated by...
Conventionally, considering the symmetry, the electric field between the concentric shells of a spherical capacitor is directed radially outward. The magnitude of the field, calculated by...
01:18Capacitor With A Dielectric
Parallel plate capacitors consist of two conducting plates separated by a certain distance. However, it is mechanically difficult to hold the large plates parallel to each other without actual contact. Hence, a dielectric layer is commonly placed between the plates, which provides an easy solution for holding the plates together with a small gap and increases the capacitance of the capacitor.
Dielectrics are non-conducting materials with no free or loosely bound electrons. When a dielectric is...
Dielectrics are non-conducting materials with no free or loosely bound electrons. When a dielectric is...
01:31Dielectric Polarization in a Capacitor
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...