Negative differential resistance and electrical bistability in nanocrystal organic memory devices

The authors observed a unique phenomenon in the Si/SiO2/Au/organic layer/Al devices in regard to negative differential resistance (NDR) and bistability. Bistability was found to be transited from the NDR by annealing the gold film before the deposition of the organic layer. Meanwhile, the on/off current ratio in the NDR region could be tuned by as much as up to six orders. By suitable manipulation, the device exhibited repeatable electrical switching behavior. The observed NDR/bistability transition behavior is speculated to have resulted from the formation of discrete gold crystals. These crystals provide more trapping sites, which collect more charges, resulting in the repulsive Coulomb interaction. (c) 2006 American Institute of Physics.