Nanotech Process Devised for Graphene Semiconductors

Helge Weman (NTNU)

Researchers at the Norwegian University of Science and Technology in Trondheim developed a process to make semiconductors by growing nanoscale wires on a graphene substrate. Helge Weman (pictured left), a professor of electronics, led the research team that published its findings last month in the journal Nano Letters; paid subscription required. Weman also co-founded a company that is taking the technology to market.

Graphene is a sheet of hexagonal carbon rings, one atom in thickness, that resembles a honeycomb. The material can conduct electricity and heat, and is among the strongest and thinnest materials ever measured. Potential uses of graphene include composite materials, flexible touchscreens, pollution sensors, and biomedical sensors.

The process devised by Weman and colleagues at NTNU (the Norwegian acronym for the university) grows nanowires made of gallium arsenide, a compound of the elements gallium and arsenic. The process for growing the nanowires is known as molecular beam epitaxy, a technique for depositing single crystals on a crystalline substrate, and already in use to make semiconductors. Inspections using electron microscopes verified the crystalline growth of nanowires with a regular hexagonal cross-sectional shape, and uniform in length and diameter.

Weman emphasizes the NTNU team’s main accomplishment was the new process for gallium arsenide semiconductors, which he calls “a template for a new production method for semiconductor devices,” leading to a platform for electronics and optoelectronics devices. Among the potential applications are nanowire solar cells that can be more efficient, less expensive, and more flexible than current solar panels, as well as smaller and more efficient electronics.

In June 2012, Weman and NTNU colleague Bjørn-Ove Fimland founded CrayoNano AS, a company in Trondheim to commercialize the technology that Crayonano licensed from NTNU. The company’s target markets are solar energy, light-emitting diodes (LEDs), thermoelectronics, piezoelectronics that generate energy from motion, and 3-D integrated circuits.

“Semiconductors grown on graphene could become the basis for new types of device systems, and could transform the semiconductor industry by introducing graphene as a preferred substrate for many applications,” says Weman. And Weman notes the semiconductor industry can quickly adopt the NTNU technology. “Our invention fits perfectly with the production machinery they already have,” he adds.

Read more:

• Simple Process Devised to Make Thin-Film Display Material
• Univ. Start-Up Developing High-Energy Light for Microchips
• Method Devised for Inexpensive Graphene Production
• Prototype Molybdenite Microchip Developed
• Semiconductor Foundation, NSF Fund Nanoelectronics Research

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