Related Experiment Video
Updated: Apr 16, 2026
15:47
Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots
Published on: November 1, 2013
17.2K
Graphene/Si-quantum-dot heterojunction diodes showing high photosensitivity compatible with quantum confinement
Dong Hee Shin1, Sung Kim, Jong Min Kim
1Department of Applied Physics and Institute of Natural Sciences, Kyung Hee University, Yongin, 446-701, Korea.
Advanced Materials (Deerfield Beach, Fla.)
|March 18, 2015
Summary
Graphene/Si quantum dot diodes show enhanced photoresponse in the near-UV range. This novel photodetector
Area of Science:
- Materials Science
- Nanotechnology
- Semiconductor Physics
Background:
- Quantum dots (QDs) offer tunable optoelectronic properties.
- Graphene possesses unique electronic characteristics.
- Heterojunctions are crucial for device applications.
Purpose of the Study:
- To report the first graphene/Si quantum dot (QD) heterojunction diodes.
- To investigate the photoresponse characteristics of these novel devices.
- To compare their performance against commercial bulk-Si photodetectors.
Main Methods:
- Fabrication of graphene/Si QD heterojunction diodes.
- Characterization of photoresponse under varying conditions.
- Analysis of the influence of QD size and graphene doping concentration.
- Investigation of the underlying photoresponse mechanism.
Main Results:
- Demonstrated a novel graphene/Si QD heterojunction diode.
- Observed photoresponse highly sensitive to QD size and graphene doping.
- Reported significantly enhanced photoresponse in the near-ultraviolet (UV) range compared to bulk-Si detectors.
- Identified carrier tunneling as the dominant photoresponse mechanism.
Conclusions:
- Graphene/Si QD heterojunctions represent a promising platform for advanced photodetectors.
- The quantum-confinement effect in QDs plays a critical role in device performance.
- Carrier tunneling facilitates efficient photocarrier collection in these devices.
Related Concept Videos
01:27Schottky Barrier Diode
1.3K
Schottky barrier diodes are specialized semiconductor devices characterized by their unique construction. This construction involves combining a metal layer with a moderately doped n-type semiconductor material. This combination leads to the formation of a Schottky barrier, a pivotal element that defines the diode's operational characteristics. The core functionality of Schottky barrier diodes is their capacity to allow current to flow in only one direction due to their distinctive...
1.3K
02:26Photoelectric Effect
41.4K
When light of a particular wavelength strikes a metal surface, electrons are emitted. This is called the photoelectric effect. The minimum frequency of light that can cause such emission of electrons is called the threshold frequency, which is specific to the metal. Light with a frequency lower than the threshold frequency, even if it is of high intensity, cannot initiate the emission of electrons. However, when the frequency is higher than the threshold value, the number of electrons ejected...
41.4K
01:16Biasing of P-N Junction
2.7K
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
2.7K
01:24Metal-Semiconductor Junctions
1.4K
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
1.4K
01:11P-N junction
1.8K
A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...
1.8K
01:27Biasing of Metal-Semiconductor Junctions
857
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
857