(a,b) SEM image
(a) and AFM topographic map (b) of a graphene monolayer on Ge(001).
Scale bars, 200 nm
(a,b); height scale bar, 11.8 nm (b). Inset of b is height (h) plotted against
projected surface
distance (d) showing the profile of the facets across the dotted line in b. (c)
LEED pattern taken
at 19 eV showing the {01} spots from the unreconstructed Ge(001)
surface (magenta)
and the {00} spots from the Ge facets (cyan). (image: Nature Communications)
(August 12, 2015) Graphene,
an atom-thick material with extraordinary properties, is a promising candidate
for the next generation of dramatically faster, more energy-efficient
electronics. However, scientists have struggled to fabricate the material into
ultra-narrow strips, called nanoribbons, that could enable the use of graphene
in high-performance semiconductor electronics.
Now, University of Wisconsin-Madison engineers have
discovered a way to grow graphene nanoribbons with desirable semiconducting
properties directly on a conventional germanium semiconductor wafer. This
advance could allow manufacturers to easily use graphene nanoribbons in hybrid
integrated circuits, which promise to significantly boost the performance of
next-generation electronic devices. The technology could also have specific
uses in industrial and military applications, such as sensors that detect
specific chemical and biological species and photonic devices that manipulate
light.
In a paper published Aug. 10 in the journal Nature
Communications, Michael Arnold, an associate professor of materials science and
engineering at UW-Madison, Ph.D. student Robert Jacobberger, and their
collaborators describe their new approach to producing graphene nanoribbons.
Importantly, their technique can easily be scaled for mass production and is
compatible with the prevailing infrastructure used in semiconductor processing.
"Graphene nanoribbons that can be grown directly on the
surface of a semiconductor like germanium are more compatible with planar
processing that's used in the semiconductor industry, and so there would be
less of a barrier to integrating these really excellent materials into
electronics in the future," Arnold says.