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` Kuniharu Takei, 32
A novel fabrication step for nanomaterials could lead to fast, energy-efficient flexible electronics.
Innovation: Kuniharu Takei, a professor at Japan’s Osaka Prefecture University, has led the development of cheap and robust methods for “printing” uniform, ultrathin patterns of different types of nanoelectronics on a wide range of surfaces.
Why it matters: Nanoscale components made of materials other than silicon could lead to more versatile, less expensive electronic devices. Transistors made from so-called compound semiconductors, for instance, could be up to twice as fast and 10 times as energy efficient as silicon transistors.
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Takei’s goal is to build circuits and sensor networks that simultaneously exploit the properties of several materials, each chosen because it offers a specific advantage. Nanomaterials made of compound semiconductors could be used to add high-speed radio-frequency components and efficient light emitters to silicon chips. But there is not yet a way to cheaply and reliably add such nanoscale components. Existing strategies involve highly specialized procedures for growing these materials on silicon or attaching them to silicon wafers; such methods are expensive and may not be practical for manufacturing. Printing processes like Takei’s could be an attractive alternative.
Methods: In the process he uses to print compound-semiconductor nanomaterials, Takei grows thin films of the chosen material on a suitable substrate, uses a lithography technique to create strips in the material, and releases the patterns from the substrate with a chemical etchant. He can then transfer the nanomaterial to a range of new surfaces, including silicon wafers and bendable plastics, by using a silicone rubber stamp that picks up the material and prints it.
Next steps: Takei’s printing methods could be used to produce electronic devices that exploit the properties of multiple materials. For example, he says, organic light-emitting diodes could be combined with transistors made of inorganic nanomaterials to make low-power, bendable displays. He’s now working on a smart bandage that would be able to sense and respond to things like glucose level and skin temperature.
—Mike Orcutt