Robots can be made made strong, robots can be made tireless, but a big problem with robots so far is that they can't be made to have a sense of touch as humans do.
The same issue challenges designers of prosthetic limbs. Imitating the motor movements of joints and muscles is one thing, but imitating human skin with all its myriad ways of detecting sensation is quite another.
Now, a team at the University of California, Berkeley, has developed a pressure-sensitive electronic material from semiconductor nanowires that they're calling "e-skin." It is the first such material made out of inorganic single crystalline semiconductors, according to the researchers.
Previous attempts to develop artificial skin have utilized organic materials. Those materials tends to be flexible and easier to work with than inorganic ones. However, organic materials do not conduct electricity well; thus, any device that used that type of artificial skin had to also use relatively high voltages to ensure proper communication of the signals.
"Inorganic materials, such as crystalline silicon, on the other hand, have excellent electrical properties and can operate on low power. They also are more chemically stable," explained team leader Ali Javey, associate professor of electrical engineering and computer sciences at Berkeley.
Using miniaturized wires made of inorganic materials can allow researchers to create a surface that is both very conductive and also very flexible. This is the kind of surface required for such applications as prosthetic limbs -- like hands -- that require great sensitivity.
The Berkeley researchers were unavailable for further comment by this story's deadline.
Scientists now are turning their attention to the other part of the feedback loop.
"How to feed those signals back to the subjects so they feel the limb," said Hsiao, "has been a problem for a long time."