查看完整版本: 研究发现石墨烯具有相变的开关行为

研究发现石墨烯具有相变的开关行为

[size=3][b]Graphene switch behaves like phase-change memory[/b][/size]Z/Q:I|+yz'^!oS

Yf T:ZIBe? [color=blue]【纳米科技世界论坛快讯】Graphene, a zero-gap semi-metal, can reversibly switch between an insulating and conductive state, according to new work by researchers in Germany. Such a result has never been reported before, either in experiments or theory, and opens up a host of new potential applications[/color].$GEZ2}$J7k H&VHoTJ
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2~6]K8Z_%j7i The graphene switch made by Tim Echtermeyer and Max Lemme of AMO in Aachen and colleagues is not much different in design to a silicon transistor (MOSFET). The researchers deposited graphene, obtained by exfoliating layers of graphite, onto a SiO2 covered silicon wafer. They then added source and drain electrodes to the device.WF$E4|W5wm"qt
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Next, the scientists covered the graphene with a silicon oxide gate insulator and top-gate electrode. "When we apply high voltages to the top gate, we believe we induce a reaction with water-related species in the gate oxide with the graphene underneath the silicon oxide gate insulator," explained Echtermeyer. jB3\;F,d i` q"SKK

,P3@HZ/b9tv Normally, the carbon pi-electrons in graphene are delocalized, which is why the material is an excellent conductor. According to the researchers, once the devices are switched off, the water-related species are chemisorbed by the graphene. This causes the carbon pi-electrons to become localized, which destroys the conductivity of the graphene. "Appropriate top-gate voltages or heating the graphene using current pulses desorbs the attached species and restores the conductivity," said Echtermeyer.E1o1j~*oR
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[b]Resistive switch[/b]
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x7v The new carbon-based "resistive" switch could find use in non-volatile memory applications and can be likened to a phase change memory, adds Echtermeyer. However, thanks to the large on/off ratio of >106 the new graphene switch could allow for multilevel memory.L;oEV@

_H,T.P$JS"bJ The team now plans to investigate how to better control its device, improve switching speed and cyclability.kr&K#U R _1s"Hu s
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"It is remarkable that graphene is fully open to controlled reversible surface modification," said Echtermeyer. "And it is exciting that molecules can be adsorbed and desorbed while graphene's electronic properties are conserved – something that may lead to new applications that were not considered feasible until now." These include non-volatile memory, sensing and multilevel logic.$m'D2K@Z|mg ^

jvW(cr The work, which was carried out as part of the ALEGRA project, was published in IEEE Electron Device Letters.
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[url=http://ieeexplore.ieee.org/xpls/abs_all.jsp?tp=&arnumber=4571159&isnumber=4571121][color=#0000ff][i]IEEE Electron Device Letters[/i] 10.1109/LED.2008.2001179[/color][/url]7{E*[wf v"VCO
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Source:  nanotechweb.org

hehe 一个新的时代可能到来了 电学电子设备的革命性发展,可称经典之作!