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.
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.