Electrical bistability in molecular films: transition from memory to threshold switching

Conductance switching in molecular layers of an organic material has been observed. With decrease in film thickness down to molecular limit, the nature of switching has changed from memory to threshold switching. The mechanisms of switching have been discussed in terms of band diagram in metal/semiconductor/metal structures. In films of several molecular layers, the carriers those are transported electroreduce organic molecules to a high-conducting state at a suitable forward bias. In the single molecular layer, direct tunneling of electrons can reduce the molecules at both bias directions. Both types of switching exhibited applications in molecular memory and logic elements. (C) 2004 Elsevier B.V.. All rights reserved.