At this stage, the modern science and technology of human civilization is based on such semiconductor materials represented by silicon. It is inseparable from solar cells to chips, but silicon is also destined to not be the most ideal due to thermal conductivity and other reasons. of semiconductor materials.
On July 22, a research team from the Massachusetts Institute of Technology, the University of Houston and other institutions discovered a material called “cubic boron arsenide” that breaks through both of these limitations, providing both electrons and holes. High mobility, excellent electrical conductivity, and extremely high thermal conductivity.
Scientists say this is the best semiconductor material ever discovered, and perhaps the best in the future. Relevant results have been published in the recent “Science” magazine, and the author column includes many Chinese, such as Chen Gang, professor of mechanical engineering at the Massachusetts Institute of Technology, and Ren Zhifeng (University of Houston), Chinese Academy of Sciences.
Of course, so far, cubic boron arsenide has only been mass-produced and tested in the lab on a small scale, and it’s not uniform. More work needs to be done to determine whether cubic boron arsenide can be manufactured in a practical, economical form, and it is still a long way from replacing silicon that is ubiquitous on Earth. But even in the near future, the material may find some uses where its unique properties have a big impact, the researchers say.
The research results involve 14 other universities including MIT, the University of Houston, the University of Texas at Austin and Boston College. Earlier research, including co-author David Broido of the new paper, theoretically predicted that the material would have high thermal conductivity, and subsequent work confirmed this. a prediction.
IT House learned that this work experimentally confirmed a prediction made by Chen Gang’s team in 2018 and completed the analysis: cubic boron arsenide also has high mobility for electrons and holes, “which makes this material really changeable. unique,” he said.
They also showed that the material has a very good band gap (energy system, which generally refers to the energy gap between the top of the valence band and the bottom of the conduction band of a semiconductor or insulator), a property that gives it great potential as a semiconductor material.
Cubic boron arsenide is the best semiconductor material
The new work confirms that boron arsenide has high electron and hole mobility, with all the major qualities required for an ideal semiconductor. “This is important because of course in semiconductors we have both positive and negative charges. So, if you’re going to make a chip, you need a material that has less resistance for both electrons and holes,” said Gang Chen.
According to reports, currently commonly used silicon has good electron mobility, but poor hole mobility, while other materials (such as gallium arsenide widely used in lasers) also have good electron mobility, but are insensitive to holes. Has good mobility.
“Heat is now a major bottleneck for many electronic products,” said Shin, lead author of the paper. “Silicon carbide is gaining traction in major electric vehicle industries, including Tesla, because despite its low electrical mobility, its The thermal conductivity is three times that of silicon. Imagine what you can achieve with boron arsenide, which has 10 times higher thermal conductivity and mobility than silicon. It’s a game changer.”
Shin adds that the electronic properties of cubic boron arsenide were initially predicted based on quantum mechanical density function calculations done by Gang Chen’s team, and these predictions have now been verified by experiments at MIT, which used optical detection to detect them. Tested with samples made by team members at the University of Houston.
The material’s thermal conductivity is not only the best of all semiconductors, but even ranks third in thermal conductivity of all materials — behind diamond and isotope-rich cubic boron nitride, the researchers say. “Now, we have also predicted the quantum mechanical behavior of electrons and holes from first principles, which has also been shown to be correct”.
“It’s impressive because I don’t actually know of any other material other than graphene that has all these properties,” he said. “It’s a bulk material with these properties.”
Of course, Gang Chen also emphasized that while its thermal and electrical properties have proven to be excellent, many other properties of this material have yet to be tested, such as its long-term stability.
“It’s probably so important that people haven’t even really paid attention to this material,” he added. Now, the ideal properties of boron arsenide have become clearer, suggesting that the material is “in many ways the best semiconductor.” .
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