A team of researchers from the Georgia Institute of Technology recently developed a revolutionary form of nanowire technology that enables artificial surfaces to detect mechanical pressure at the same level of sensitivity as would a human finger.
Previous attempts to create an artificial sense of touch have relied largely on the use of control gates within microcircuits as well as changes in wire capacitance or resistance caused by external pressure (1). These designs met limited success however, because they can only permit comparatively low sensor densities and tend to lose sensitivity upon mechanical deformations of their supporting substrates (1).
The new technology, explains Georgia Tech professor Zhong Lin Wang, eliminates the use of control gates, and instead exploits tiny electrical currents produced by piezoelectric crystals, a type of semiconducting material, in response to mechanical pressure (1,2).
The design features arrays of zinc oxide nanowires that transmit electrical charge from iezotronic transistors (2). The piezoelectric nature of the zinc oxide material enables the structure to function without the supply of outside current or electrical gates, providing the new arrangement with over 15 times the sensor density and spatial resolution compared to existing pressure-sensing technology, and pressure sensitivity comparable to that of the skin on human fingertips (1). The wires can also be embedded within almost any substrate material and do not lose sensitivity as a result of deformations of the base substrate (1).
This new mode of sensing holds great promise for areas such as human-computer interface and robotics (2). For example, the high sensitivity of the transistors can be utilized to record electronic signatures by sensing the pressure a digital pen exerts while an individual is signing (2). The sensors’ piezoelectric properties could also potentially allow engineers to control electrical devices solely through manipulations of mechanical pressure (1). Perhaps the most exciting implication of the invention is the prospect of creating robotic or prostatic arms with a human-like sense of touch (2).
The researchers who developed the technology at Georgia Tech are now working toward creating a system capable of interpreting these piezoelectric signals and using them to perform these more complex functions (1).
- Orcutt, Mike, NanoScale Pressure Sensors Mimic Human Skin, (2013). Available at http://www.technologyreview.com/news/514131/nanoscale-pressure-sensors-mimic-human-skin/
- ‘Smart Skin’ Hope for Touch Sensor, (2013). Available at http://www.bbc.co.uk/news/science-environment-22302487