As the electronics industry works toward developing smaller and more compact devices, the need to create new types of scaled-down semiconductors that are more efficient and use less power has become essential.
In a study to be published in the April issue of Nature Materials (currently available online), researchers from UCLA's Henry Samueli School of Engineering and Applied Science describe the creation of a new material incorporating spintronics that could help usher in the next generation of smaller, more affordable and more power-efficient devices.
While conventional complementary metal-oxide semiconductors (CMOS), a technology used today in all types of electronics, rely on electrons' charge to power devices, the emerging field of spintronics exploits another aspect of electrons — their spin, which could be manipulated by electric and magnetic fields.
"With the use of nanoscaled magnetic materials, spintronics or electronic devices, when switched off, will not have a stand-by power dissipation problem. With this advantage, devices with much lower power consumption, known as non-volatile electronics, can become a reality," said the study's corresponding author, Kang L. Wang, Raytheon Professor of Electrical Engineering at UCLA Engineering, whose team carried out the research. "Our approach provides a possible solution to address the critical challenges facing today's microelectronics industry and sheds light on the future of spintronics."
"We've built a new class of material with magnetic properties in a dilute magnetic semiconductor (DMS) system," said Faxian Xiu, a UCLA senior researcher and lead author of the study. "Traditionally, it's been really difficult to enhance the ferromagnetism of this material above room temperature. However in our work, by using a type of quantum structure, we've been able to push the ferromagnetism above room temperature."
Ferromagnetism is the phenomenon by which certain materials form permanent magnets. In the past, the control of magnetic properties has been accomplished by applying an electric current. For example, passing an electric current will generate magnetic fields. Unfortunately, using electric currents poses significant challenges for reducing power consumption and for device miniaturization.
"You can think of a transformer, which passes a current to generate a magnetic field. This will have huge power dissipation (heat)," Xiu said. "In our study, we tried to modulate the magnetic properties of DMS without passing the current."
Ferromagnetic coupling in DMS systems, the researchers say, could lead to a new breed of magneto-electronic devices that alleviate the problems related to electric currents. The electric field–controlled ferromagnetism reported in this study shows that without passing an electric current, electronic devices could be operated and functioning based on the collective spin behavior of the carriers. This holds great promise for building next-generation nanoscaled integrated chips with much lower power consumption.
To achieve the ferromagnetic properties, Kang's group grew germanium dots on a silicon p-type substrate, creating quantum dots on top of the substrate. Silicon and germanium are ideal candidates because of their excellent compatibility and ability to be incorporated within conventional CMOS technology. The quantum dots, which are themselves semiconductors, would then be utilized in building new devices.
"To demonstrate possible applications of these fantastic quantum dots, we fabricated metal-oxide semiconductor devices and used these dots as the channel layer. By applying an electric field, we are able to control the hole concentration inside the dots and thus modulate their ferromagnetism," Xiu said.
"This finding is significant in the sense that it opens up a completely new paradigm for next-generation microelectronics, which takes advantage of the spin properties of carriers, in addition to the existing charge transport as envisaged in the conventional CMOS technology."
The key is to be able to use this material at room temperature.
"The material is not very useful if it doesn't work at room temperature," Wang said. "We want to be able to use it anywhere. In this work, we've achieved success on electric field–controlled ferromagnetism at 100 degrees Kelvin and are moving towards room temperature. We feel strongly that we'll be able to accomplish this. Once we've achieved room-temperature controllability, we'll be able to start building real devices to demonstrate its viability in non-volatile electronic devices."
Study collaborators Jin Zou, professor of material engineering, and postdoctoral fellow Yong Wang, both from the University of Queensland, Australia, also contributed significantly to this work.
The study was funded by the Center for Functional Engineered Nano Architectronics (FENA), the Western Institute of Nanoelectronics (WIN) at UCLA Engineering, and in part by Intel Corp. and the Australian government.
The UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs, including an interdepartmental graduate degree program in biomedical engineering. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to eight multimillion-dollar interdisciplinary research centers in wireless sensor systems, nanotechnology, nanomanufacturing and nanoelectronics, all funded by federal and private agencies.
For more news, visit the UCLA Newsroom and follow us on Twitter.
Wileen Wong Kromhout | EurekAlert!
Further reports about: > Applied and Environmental Microbiology > CMOS > CMOS technology > DMS > Ferchau Engineering > Science TV > UCLA > electric field > electronic devices > electronics industry > magnetic field > magnetic material > power consumption > quantum dot > room temperature > semiconductor device
New design improves performance of flexible wearable electronics
23.06.2017 | North Carolina State University
Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
27.06.2017 | Earth Sciences
27.06.2017 | Earth Sciences
27.06.2017 | Life Sciences