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Graphene key to two-dimensional semiconductor with extraordinary properties

Monday, August 29, 2016
An illustration of the Migration Enhance Encapsulated Growth (MEEG) process to stabilize novel wide-bandgap two-dimensional nitride semiconductors that are not naturally occurring. MEEG is facilitated by defects in the graphene lattice that act as pathways for intercalation. When the gallium and nitrogen atoms meet at the graphene/SiC interface, they chemically react to form two-dimensional gallium nitride. Image: Z. Al Balushi and Stephen Weitzner / Penn State MatSE

A newly discovered method for making two-dimensional materials could lead to new and extraordinary properties, particularly in a class of materials called nitrides, say the Penn State materials scientists who discovered the process. This first-ever growth of two-dimensional gallium nitride using graphene encapsulation could lead to applications in deep ultraviolet lasers, next-generation electronics and sensors.

"These experimental results open up new avenues of research in 2D materials," says Joshua Robinson, associate professor of materials science and engineering. "This work focuses on making 2D gallium nitride, which has never been done before."

Gallium nitride in its three-dimensional form is known to be a wide-bandgap semiconductor. Wide-bandgap semiconductors are important for high frequency, high power applications. When grown in its two-dimensional form, gallium nitride transforms from a wide-bandgap material to an ultrawide-bandgap material, effectively tripling the energy spectrum it can operate in, including the whole ultraviolet, visible and infrared spectrum. This work will have a particular impact on electro-optic devices that manipulate and transmit light.