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What Can Happen When Graphene Meets a Semiconductor

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UWM doctoral student Shivani Rajput and fellow postdoc researchers Yaoyi Li (left) and Mingxing Chen.

UWM doctoral student Shivani Rajput, first author on the paper, shows a reconstructed image of graphene with the ripples clearly visible. Two postdoctoral researchers also worked on the project: Yaoyi Li (left) and Mingxing Chen.

Credit: Troye Fox

Although graphene is touted as a material that could be used to build next-generation electronics and quantum computers, much is unknown about how it controls an electric current. University of Wisconsin-Milwaukee (UWM) researchers say they have identified new characteristics of electron transport in a two-dimensional sheet of graphene layered on top of a semiconductor.

The researchers demonstrated that when electrons are rerouted at the interface of the graphene and its semiconducting substrate, they encounter what is known as a Schottky barrier. If the Schottky barrier is deep enough, electrons do not pass, unless rectified by applying an electric field, which the researchers say is a promising mechanism for turning a graphene-based device on and off. The researchers also found that intrinsic ripples form on graphene when it is placed on top of a semiconductor, which affects the height of the barrier.

"Our study says that ripples affect the barrier height and even if there's a small variation in it, the results will be a large change in the electron transport," says UWM professor Li Lian. The barrier needs to be a consistent height across the whole sheet in order to ensure that the current is either on or off, the researchers note.

From UWM News
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Abstracts Copyright © 2013 Information Inc., Bethesda, Maryland, USA


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