University of California, Riverside

Department of Electrical and Computer Engineering

Graduate Students Research in Balandin Laboratory Published in Nature Communications - Highlighted in Media

Graduate Students Research in Balandin Laboratory Published in Nature Communications....

Graduate Students Research in Balandin Laboratory Published in Nature Communications - Highlighted in Media

May 21, 2012

Gallium Nitride (GaN) is a semiconductor used in transistors and light-emitting diodes. GaN offers advantages in high-power electronics, especially in automotive and electric car applications, radars and communication devices. However, the market share of GaN electronics is limited owing to difficulties of heat removal. The side product of high-power operation is large amount of dissipated heat, which leads to device degradation and breakdown. The Nano-Device Laboratory (NDL) research group of Prof. Balandin, Professor of Electrical Engineering and Founding Chair of Materials Science and Engineering program at UCR found an unusual solution for the thermal management problem of GaN technology. They demonstrated that heat removal from GaN transistors can be substantially improved via introduction of alternative heat-escaping channels implemented with graphene multilayers – excellent heat conductors. The new approach to thermal management of power electronics was reported this month in Nature Communications (

The breakthrough in thermal management was achieved by Prof. Balandin together with three of his EE graduate students: Guanxiong Liu, Zhong Yan and Javed Khan. Guanxiong Liu and Zhong Yan are currently PhD candidates (see Photo) while Javed Khan has already defended his PhD and started to work at Intel.  Prof. Balandin – recipient of IEEE Nanotechnology Pioneer Award for 2011 – has previously discovered that graphene is an excellent heat conductor. Few-layer graphene films preserve their excellent thermal properties even when their thickness is only a few nanometers, which is unlike metal or semiconductor films. The latter makes them excellent candidates for applications as the lateral heat spreaders and interconnects.

The work on thermal management of GaN transistors with graphene quilts was supported by the US Office of Naval Research (ONR), Semiconductor Research Corporation (SRC) and the Defense Advanced Research Project Agency (DARPA). The Nature Communication paper with these results was highlighted in media worldwide, including Physics World, Phys.Org, NanoWerk, EE India Times and others. The UCR story is linked here.

Photo (from left to right): Researchers involved in the demonstration of graphene quilts for GaN power transistors. From left to right: PhD Candidate Guanxiong Liu, Prof. Alexander Balandin, and PhD Candidate Zhong Yan in Nano-Device Laboratory at UCR. The panel below shows graphene etching into NDL and UCR logos. The dark color regions are graphene and the light color is the substrate.

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