联系我们  |  网站地图  |  English   |  移动版  |  中国科学院 |ARP
站内搜索:
首页 简介 管理部门 科研部门 支撑部门 研究队伍 科研成果 成果转化 研究生教育 党建与创新文化 科普 信息公开 办公内网 OA系统
科技信息
清华大学在力学结构超材料...
科学家发明光催化水裂解新...
摩擦/力致发光研究取得进展
Physicists uncover why n...
New photodetector could ...
科学家为设计手性发光材料...
二维本征铁磁半导体研究获...
3D打印材料可磁化形变
Nobarrier to application...
Turbocharge for lithium ...
层状钒酸钾K0.5V2O5用于非...
石墨烯等离激元寿命的新突破
西安交大多模式微纳平台实...
The physics of better ba...
Research shows graphene ...
现在位置:首页>新闻动态>科技信息
Researchers control the properties of graphene transistors using pressure
2018-05-17 09:08:52 | 【 【打印】【关闭】

By compressing layers of boron nitride and graphene, researchers were able to enhance the material's band gap, bringing it one step closer to being a viable semiconductor for use in today's electronic devices. Credit: Philip Krantz

  A Columbia University-led international team of researchers has developed a technique to manipulate the electrical conductivity of graphene with compression, bringing the material one step closer to being a viable semiconductor for use in today's electronic devices.

  "Graphene is the best electrical conductor that we know of on Earth," said Matthew Yankowitz, a postdoctoral research scientist in Columbia's physics department and first author on the study. "The problem is that it's too good at conducting electricity, and we don't know how to stop it effectively. Our work establishes for the first time a route to realizing a technologically relevant band gap in graphene without compromising its quality. Additionally, if applied to other interesting combinations of 2-D materials, the technique we used may lead to new emergent phenomena, such as magnetism, superconductivity, and more."

  The study, funded by the National Science Foundation and the David and Lucille Packard Foundation, appears in the May 17 issue ofNature.

  The unusual electronic properties of graphene, a two-dimensional (2-D) material comprised of hexagonally-bonded carbon atoms, have excited the physics community since its discovery more than a decade ago. Graphene is the strongest, thinnest material known to exist. It also happens to be a superior conductor of electricity—the unique atomic arrangement of the carbon atoms in graphene allows its electrons to easily travel at extremely high velocity without the significant chance of scattering, saving precious energy typically lost in other conductors.

  But turning off the transmission of electrons through the material without altering or sacrificing the favorable qualities of graphene has proven unsuccessful to-date.

  "One of the grand goals in graphene research is to figure out a way to keep all the good things about graphene but also create a band gap—an electrical on-off switch," said Cory Dean, assistant professor of physics at Columbia University and the study's principal investigator. He explained that past efforts to modify graphene to create such a band gap have degraded the intrinsically good properties of graphene, rendering it much less useful. One superstructure does show promise, however. When graphene is sandwiched between layers of boron nitride (BN), an atomically-thin electrical insulator, and the two materials are rotationally aligned, the BN has been shown to modify the electronic structure of the graphene, creating a band gap that allows the material to behave as a semiconductor—that is, both as an electrical conductor and an insulator. The band gap created by this layering alone, however, is not large enough to be useful in the operation of electrical transistor devices at room temperature. 

  In an effort to enhance this band gap, Yankowitz, Dean, and their colleagues at the National High Magnetic Field Laboratory, the University of Seoul in Korea, and the National University of Singapore, compressed the layers of the BN-graphene structure and found that applying pressure substantially increased the size of the band gap, more effectively blocking the flow of electricity through the graphene.

  "As we squeeze and apply pressure, the band gap grows," Yankowitz said. "It's still not a big enough gap—a strong enough switch—to be used in transistor devices at room temperature, but we have gained a fundamentally better understanding of why this band gap exists in the first place, how it can be tuned, and how we may target it in the future. Transistors are ubiquitous in our modern electronic devices, so if we can find a way to use graphene as a transistor it would have widespread applications."

  Yankowitz added that scientists have been conducting experiments at high pressures in conventional three-dimensional materials for years, but no one had yet figured out a way to do them with 2-D materials. Now, researchers will be able to test how applying various degrees of pressure changes the properties of a vast range of combinations of stacked 2-D materials.

  "Any emergent property that results from the combination of 2-D materials should grow stronger as the materials are compressed," Yankowitz said. "We can take any of these arbitrary structures now and squeeze them and the strength of the resulting effect is tunable. We've added a new experimental tool to the toolbox we use to manipulate 2-D materials and that tool opens boundless possibilities for creating devices with designer properties."

  Explore further: Scientists move graphene closer to transistor applications 

  More information: Dynamic band - structure tuning of graphene moiré superlattices with pressure,Nature (2018). nature.com/articles/doi:10.1038/s41586-018-0107-1    

  Journal reference: Nature  

版权所有 中国科学院上海硅酸盐研究所 沪ICP备05005480号-1
长宁园区地址:上海市长宁区定西路1295号 电话:86-21-52412990 传真:86-21-52413903 邮编:200050
嘉定园区地址:上海市嘉定区和硕路585号  电话:86-21-69906002 传真:86-21-69906700 邮编:201899