Home > Press > Getting electrons to move in a semiconductor: Gallium oxide shows high electron mobility, making it promising for better and cheaper devices
![]() |
Schematic stack and the scanning electron microscopic image of the β-(AlxGa1-x)2O3/Ga2O3 modulation-doped field effect transistor. CREDIT Choong Hee Lee and Yuewei Zhang |
Abstract:
The next generation of energy-efficient power electronics, high-frequency communication systems, and solid-state lighting rely on materials known as wide bandgap semiconductors. Circuits based on these materials can operate at much higher power densities and with lower power losses than silicon-based circuits. These materials have enabled a revolution in LED lighting, which led to the 2014 Nobel Prize in physics.
In new experiments reported in Applied Physics Letters, from AIP Publishing, researchers have shown that a wide-bandgap semiconductor called gallium oxide (Ga2O3) can be engineered into nanometer-scale structures that allow electrons to move much faster within the crystal structure. With electrons that move with such ease, Ga2O3 could be a promising material for applications such as high-frequency communication systems and energy-efficient power electronics.
"Gallium oxide has the potential to enable transistors that would surpass current technology," said Siddharth Rajan of Ohio State University, who led the research.
Because Ga2O3 has one of the largest bandgaps (the energy needed to excite an electron so that it's conductive) of the wide bandgap materials being developed as alternatives to silicon, it's especially useful for high-power and high-frequency devices. It's also unique among wide bandgap semiconductors in that it can be produced directly from its molten form, which enables large-scale manufacturing of high-quality crystals.
For use in electronic devices, the electrons in the material must be able to move easily under an electric field, a property called high electron mobility. "That's a key parameter for any device," Rajan said. Normally, to populate a semiconductor with electrons, the material is doped with other elements. The problem, however, is that the dopants also scatter electrons, limiting the electron mobility of the material.
To solve this problem, the researchers used a technique known as modulation doping. The approach was first developed in 1979 by Takashi Mimura to create a gallium arsenide high-electron mobility transistor, which won the Kyoto Prize in 2017. While it is now a commonly used technique to achieve high mobility, its application to Ga2O3 is something new.
In their work, the researchers created a so-called semiconductor heterostructure, creating an atomically perfect interface between Ga2O3 and its alloy with aluminum, aluminum gallium oxide -- two semiconductors with the same crystal structure but different energy gaps. A few nanometers away from the interface, embedded inside the aluminum gallium oxide, is a sheet of electron-donating impurities only a few atoms thick. The donated electrons transfer into the Ga2O3, forming a 2-D electron gas. But because the electrons are now also separated from the dopants (hence the term modulation doping) in the aluminum gallium oxide by a few nanometers, they scatter much less and remain highly mobile.
Using this technique, the researchers reached record mobilities. The researchers were also able to observe Shubnikov-de Haas oscillations, a quantum phenomenon in which increasing the strength of an external magnetic field causes the resistance of the material to oscillate. These oscillations confirm formation of the high mobility 2-D electron gas and allow the researchers to measure critical material properties.
Rajan explained that such modulation-doped structures could lead to a new class of quantum structures and electronics that harnesses the potential of Ga2O3.
####
About American Institute of Physics
Applied Physics Letters features concise, rapid reports on significant new findings in applied physics. The journal covers new experimental and theoretical research on applications of physics phenomena related to all branches of science, engineering, and modern technology. See http://apl.aip.org .
For more information, please click here
Contacts:
Julia Majors
301-209-3090
Copyright © American Institute of Physics
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related Links |
Related News Press |
News and information
Photonic synapses with low power consumption and high sensitivity are expected to integrate sensing-memory-preprocessing capabilities July 1st, 2022
New protocol for assessing the safety of nanomaterials July 1st, 2022
Boron nitride nanotube fibers get real: Rice lab creates first heat-tolerant, stable fibers from wet-spinning process June 24th, 2022
2 Dimensional Materials
Controlled synthesis of crystal flakes paves path for advanced future electronics June 17th, 2022
Solving the puzzle of 2D disorder: An interdisciplinary team developed a new method to characterize disorder in 2D materials June 17th, 2022
UBCO researchers change the game when it comes to activity tracking: Flexible, highly sensitive motion device created by extrusion printing June 17th, 2022
Bumps could smooth quantum investigations: Rice University models show unique properties of 2D materials stressed by contoured substrates June 10th, 2022
UCI scientists turn a hydrogen molecule into a quantum sensor: New technique enables precise measurement of electrostatic properties of materials April 22nd, 2022
Display technology/LEDs/SS Lighting/OLEDs
A solution to perovskite solar cell scalability problems April 22nd, 2022
Hardware
A Carbon Nanotube Microprocessor Mature Enough to Say Hello: Three new breakthroughs make commercial nanotube processors possible March 2nd, 2020
Powering the future: Smallest all-digital circuit opens doors to 5 nm next-gen semiconductor February 11th, 2020
Do you Kyoto? World-leading companies share their approaches to environmentally friendly business at NAUM’19 October 14th, 2019
Possible Futures
Photonic synapses with low power consumption and high sensitivity are expected to integrate sensing-memory-preprocessing capabilities July 1st, 2022
New protocol for assessing the safety of nanomaterials July 1st, 2022
Solving the solar energy storage problem with rechargeable batteries that can convert and store energy at once June 24th, 2022
Chip Technology
Photonic synapses with low power consumption and high sensitivity are expected to integrate sensing-memory-preprocessing capabilities July 1st, 2022
Boron nitride nanotube fibers get real: Rice lab creates first heat-tolerant, stable fibers from wet-spinning process June 24th, 2022
Nanoelectronics
Controlled synthesis of crystal flakes paves path for advanced future electronics June 17th, 2022
Eyebrow-raising: Researchers reveal why nanowires stick to each other February 11th, 2022
Visualizing temperature transport: An unexpected technique for nanoscale characterization November 19th, 2021
Discoveries
Photonic synapses with low power consumption and high sensitivity are expected to integrate sensing-memory-preprocessing capabilities July 1st, 2022
New protocol for assessing the safety of nanomaterials July 1st, 2022
Flexing the power of a conductive polymer: A new material holds promise for the next generation of organic electronics June 24th, 2022
Materials/Metamaterials
New protocol for assessing the safety of nanomaterials July 1st, 2022
Nanotubes: a promising solution for advanced rubber cables with 60% less conductive filler June 1st, 2022
New route to build materials out of tiny particles May 27th, 2022
A one-stop shop for quantum sensing materials May 27th, 2022
Announcements
Photonic synapses with low power consumption and high sensitivity are expected to integrate sensing-memory-preprocessing capabilities July 1st, 2022
New protocol for assessing the safety of nanomaterials July 1st, 2022
Boron nitride nanotube fibers get real: Rice lab creates first heat-tolerant, stable fibers from wet-spinning process June 24th, 2022
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Photonic synapses with low power consumption and high sensitivity are expected to integrate sensing-memory-preprocessing capabilities July 1st, 2022
New protocol for assessing the safety of nanomaterials July 1st, 2022
Solving the solar energy storage problem with rechargeable batteries that can convert and store energy at once June 24th, 2022
Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records
Solving the solar energy storage problem with rechargeable batteries that can convert and store energy at once June 24th, 2022
Boron nitride nanotube fibers get real: Rice lab creates first heat-tolerant, stable fibers from wet-spinning process June 24th, 2022
![]() |
||
![]() |
||
The latest news from around the world, FREE | ||
![]() |
![]() |
||
Premium Products | ||
![]() |
||
Only the news you want to read!
Learn More |
||
![]() |
||
Full-service, expert consulting
Learn More |
||
![]() |