Physical movement stored as memory in a microchip could lead to advances in touch screens, robot control devices and medical implants. Researchers are arraying nanowires on a microchip to form a write-read memory cell as part of ongoing work that could convert motions, such as a hand in a glove or pressing a display, into memory. Moving or putting pressure on the nanowires creates an electrical current that can be read and recorded as memory. Arrays of such cells offer the potential for a variety of user interface applications and for new ways to convert mechanical or biological actions into electronic data.
Developed by researchers at the Georgia Institute of Technology (Georgia Tech), the piezoelectrically modulated resistive memory (PRM) system relies on the piezoelectric effect, where some materials, in this case zinc oxide nanowires, will generate electrical current when they are put under pressure or moved, which causes them to temporarily bend or deform. Piezoelectric materials also create mechanical strain (movement) when they are exposed to an electric current. PRM technology allows the creation of a new type of transistor that is switched on or off through movement or mechanical activity, explains Zhong Lin Wang, regents professor in Georgia Tech’s School of Material Science and Engineering in Atlanta.
Current memory systems, such as flash memory, are mainly if not entirely electronic, Wang says. But PRM technology allows the direct writing of electrical or optical memory through physical means. “Once you introduce the piezoelectric effect into the memory, you talk about the memory of strain and stress,” Wang notes.