Related Experiment Video
Updated: May 11, 2026
15:47
Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots
Published on: November 1, 2013
GdN nanoisland-based GaN tunnel junctions.
Sriram Krishnamoorthy1, Thomas F Kent, Jing Yang
1Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210, USA.
Nano Letters
|May 14, 2013
Summary
Gadolinium nitride (GdN) nanoislands significantly improve hole injection in gallium nitride (GaN) p-n junctions. This breakthrough enables lower resistance tunnel junctions for efficient light-emitting diodes and lasers.
Area of Science:
- Materials Science
- Semiconductor Physics
- Optoelectronics
Background:
- Gallium nitride (GaN) and aluminum nitride (AlN)-based devices face challenges with hole injection and p-contacts.
- Efficient tunnel junctions are crucial for advanced optoelectronic devices like LEDs and lasers.
Purpose of the Study:
- To demonstrate GdN nanoislands for enhancing interband tunneling and hole injection in GaN p-n junctions.
- To achieve low specific resistivity in tunnel junctions for wide bandgap semiconductors.
Main Methods:
- Fabrication of GaN p-n junctions incorporating GdN nanoisland layers.
- Characterization of tunnel junction properties, including specific resistivity.
- Low-temperature electroluminescence measurements to confirm tunnel injection.
Main Results:
- GdN nanoislands enhanced hole injection by several orders of magnitude.
- Achieved a low tunnel junction specific resistivity of 1.3 × 10(-3) Ω-cm(2).
- Confirmed tunnel injection via low-temperature operation (down to 20 K) with strong electroluminescence.
Conclusions:
- GdN nanoislands effectively overcome hole injection challenges in GaN devices.
- The low resistance and low optical absorption of GdN are highly promising for GaN-based light emitters.
- This approach offers a pathway to improved performance in wide bandgap optoelectronics.
Related Concept Videos
01:24Metal-Semiconductor Junctions
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 semiconductor's...
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 semiconductor's...
01:11P-N junction
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...
01:37Gap Junctions
Multicellular organisms employ a variety of ways for cells to communicate with each other. Gap junctions are specialized proteins that form pores between neighboring cells in animals, connecting the cytoplasm between the two, and allowing for the exchange of molecules and ions. They are found in a wide range of invertebrate and vertebrate species, mediate numerous functions including cell differentiation and development, and are associated with numerous human diseases, including cardiac and...
01:27Gap Junctions
The cytoplasm of adjacent animal cells can exchange small molecules, ions, and secondary messengers via the communication channels which form the gap junctions. These junctions comprise a few hundred to thousands of molecular channels, each made of two halves, called the connexon hemichannel. A connexon is a hexamer of six transmembrane connexin proteins, which assemble radially, thus forming a pore or channel in the center. One connexon hemichannel docks with a corresponding connexon on the...
01:22Semiconductors
There is variation in the electrical conductivity of materials - metals, semiconductors, and insulators that are showcased with the help of the energy band diagrams.
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...
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...
01:27Biasing of Metal-Semiconductor Junctions
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...