Friday, July 29, 2011

Warmed-Up Organic Memory Transistor Has Larger Memory Capacity

Scientists show that non-volatile memory made from a sandwich of silver nanoparticle-laced plastic retains its on/off state over a wider voltage range when operating at toasty temperatures.

Plastics are cheap, flexible, and relatively easy to manufacture, but they can also be more heat sensitive than other materials such as metals. The same goes for plastic (or organic) electronics, which offer the promise of foldable displays or thin, inexpensive devices, but react to temperature swings differently than traditional silicon-based electronics. 

So, researchers at the Hong Kong Polytechnic University decided to explore this temperature-dependent behavior more closely. They took a non-volatile organic memory transistor, made from the plastic pentacene and a layer of silver nanoparticles, and heated the device to 90 degrees Celsius. After initial heating, the distribution of nanoparticles changed, with particles clumping together in larger groups. Also, the memory window of the device — the voltage range over which it retained an original on or off state — at first decreased. 

However, when researchers cycled the heat following the one-time structural change, they found that higher operating temperatures meant a larger memory window. The results appear in the AIP's Applied Physics Letters. The heat and memory window relationship could be put to use in temperature-sensing applications, such as measuring and storing the temperature profile of an object, the researchers write.

Contacts and sources:
Catherine Meyers
American Institute of Physics

Article: "Thermal annealing and temperature dependences of memory effect in organic memory transistor" is accepted for publication in Applied Physics Letters.

Authors: X.C. Ren (1), S.M. Wang (1), C.W. Leung (2), F. Yan (2) and P.K.L. Chan (1)

(1) Department of Mechanical Engineering, Hong Kong Polytechnic University, Hong Kong
(2) Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong

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