Graphene Nanoribbons Grown on Germanium

[Guest_Jim_*]

After the electrical properties of graphene were discovered, many started working on ways to use the atom-thick material. While there are a tremendous number of possible applications, we have been struggling to find ways to grow enough graphene in the proper form to be useful. At least for some applications now, researchers at the University of Wisconsin, Madison have discovered a means to efficiently grow graphene on the semiconductor germanium.

For graphene to be useful in semiconductors applications, it has to be in the form of nanoribbons less than 10 nm wide, and have smooth armchair edges. Typical means of making graphene with this geometry though would involve either cutting apart sheets into the ribbons, leaving rough edges, or growing the ribbons on a metal substrate. The catch with the metal substrate is that the nanoribbons would be too short. The solution the Wisconsin researchers discovered is that when you grow graphene on a germanium substrate, its properties can be controlled by manipulating how much methane, the carbon source in the process, is used. The graphene growing on the germanium naturally forms long nanoribbons with the desirable armchair edges, and can be made less than 10 nm wide.

While this discovery indicates it path to the desired graphene nanoribbons, there is still more work to do as the nanoribbons grow at random spots on the substrate, and in random directions. The researchers are now working to control the growth and alignment of the nanoribbons.

Source: University of Wisconsin, Madison

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