writes Electronics printed on paper promise to be cheap, flexible, and recyclable, and could lead to applications such as smart labels on foods and pharmaceuticals or as wearable medical sensors. Many engineers have managed to print transistors and solar cells on paper, but one key component of a smart device has been missing—memory. Now a group of researchers has developed a method that uses ink-jet technology to print resistive random access memory on an ordinary letter sized piece of paper. The memory is robust: Engineers could bend the device 1,000 times without any loss of performance.
The memory is not yet very dense, but could be: "Each silver dot they printed was approximately 50 microns across and separated from its neighbor by 25 microns, so each bit of memory is 100 microns on a side. At that size, a standard 8.5- by 11-inch piece of paper can hold 1 MB of memory. Der-Hsien Lien, the paper's lead author, says existing ultrafine ink-jet technology can produce dots less than 1 micron across, which would allow the same piece of paper to hold 1 gigabyte. Reading and writing the bits takes 100 to 200 microseconds"