Organic Quantum Wells: Molecular Rectification and Single-Electron Tunnelling

Abstract

We present the first direct observation of molecular rectification as a consequence of asymmetric tunnelling process through molecular quantum wells. In addition, single-electron tunnelling effects were observed which might be attributed to the charging of single molecules or molecular stacks. As molecular systems we used LB-film-based heterostructures consisting of an octasubstituted metallophthalocyanine and a perylene-3,4,9,10-tetracarboxyldiimide derivative sandwiched between two gold electrodes. By using a special thermal evaporation technique to deposit the top gold electrode, we have overcome the problem of short circuits and were able to fabricate highly reproducible devices.