Zero-dimensional quantum dots identified by University of Cincinnati researchers could someday have a big effect on a variety of technologies, such as solar energy, lasers and medical diagnostics.
In physics, there's small, and then there's nullity – as in zero-dimensional.
UC student Teng Shi will present her semiconductor nanowire research at the American Physical Society meeting.
University of Cincinnati researchers have reached this threshold with a special structure that may someday lead to better ways of harnessing solar energy, stronger lasers or more sensitive medical diagnostic devices.
These structures are semiconductor nanowires. UC doctoral student Teng Shi says she and a team of researchers have observed unique optical signatures indicating that electronic excitations within these nanowires can be confined to a zero-dimensional state called a "quantum dot."
This latest discovery is all about going small, but its significance is anything but. The research team’s ability to control the confinement energy by varying the size of the quantum dot opens up a world of possibilities.
"Exploring the basic physics of semiconductor nanowires enables one to envision applications or to design structures for applications," says Shi of UC's Department of Physics. "These structures are potential candidates for a variety of applications including photovoltaics, lasers and ultra-sensitive nanosensors."
Shi will present the team's research "Temperature-dependent Photoluminescence Imaging of GaAs/AlGaAs Heterostructure Quantum Well Tubes" at the American Physical Society (APS) meeting to be held March 3-7 in Denver. Nearly 10,000 professionals, scholars and students will attend the APS meeting to discuss new research from industry, universities and laboratories from around the world.
This research advances work previously done on semiconductor nanowires at UC. By using a thin shell called a quantum well tube and growing it – to about 4 nanometers thick – around the nanowire core, researchers found electrons within the nanowire were distributed in an unusual way in relation to the facets of the hexagonal tube. The result is a quantum wire, like a long string many times thinner than a human hair.
Now they've taken things even further, going from one-dimensional wires to zero-dimensional quantum dots. These little structures could have a big effect on a variety of technologies. Semiconductors are at the center of modern electronics. Computers, TVs and cellphones have them. They’re made from the crystalline form of elements that have scientifically beneficial electrical conductivity properties. Many semiconductors are made of silicon, but gallium arsenide is used in this research.
Additional contributors to this research are UC physics professors Howard Jackson and Leigh Smith in the McMicken College of Arts and Sciences; Jan Yarrison-Rice of Miami University; and Nian Jiang, Hoe Tan, Qiang Gao and Chennupati Jagadish of Australian National University.
The team at UC is one of only about a half dozen in the U.S. conducting competitive research in the field, and UC’s efforts in this area are partially funded by the National Science Foundation. The team's big achievements in the science of small support the UC2019 Academic Master Plan by producing new ways of understanding and transforming the world through research and scholarship.
Tom Robinette | EurekAlert!
Taking a spin on plasma space tornadoes with NASA observations
20.11.2017 | NASA/Goddard Space Flight Center
NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
20.11.2017 | Earth Sciences
20.11.2017 | Earth Sciences
20.11.2017 | Life Sciences