Researchers at the University of California, Berkeley have developed a new type of artificial skin out of inorganic single crystalline semiconductors. Previous attempts at creating pressure-sensitive skin have relied on organic materials because they are more flexible and easier to process, but their poor semiconducter properties often require high voltages to operate the circuitry, limiting their use.
A new process now allows the use of inorganic material. It grows germanium/silicon nanowires on a cylindrical drum and then rolls them onto a sticky substrate in an orderly fashion, forming the basis from which thin, flexible sheets of electronic materials can be built. For the e-skin, nanowires were printed onto an 18 by 19 pixel matrix measuring 7 centimeters on each side, creating one transistor per matrix field. The transistors were then integrated with a pressure sensitive rubber to provide the sensing functionality. The final patch of skin required less than 5 volts of power to operate and maintained its robustness after being subjected to more than 2,000 bending cycles.
The researchers are now thinking about scaling up their approach.