Insulator Film Thickness to Fix the Spacing between Electrodes to Molecular Length Scale

Successful fabrication of reliable and scalable molecular electrodes is a major challenge in the making practical molecular electronics devices. Most of the present day molecular electrodes suffer with short circuit, scalability, and reproducibility problems. Moreover only few metals, gold (Au) is the mostly used one, can be utilized due to limitations with current molecular electrode design. We have come up with a new approach that is not only reliable but also allows the use of wide range of metals, including magnetic metals, in molecular electrodes. We have prepared novel molecular electrodes utilizing the exposed edge of metal-insulator-metal cross junction. As much as 50 fold increase over bare tunnel junction current was noticed following molecule attachment. The molecular electrodes with as high as 90% yield and 10 months long device life, were produced by using optical photolithography and sputtering deposition method. Major obstacle in the fabrication of molecular electrode was the adverse effects of mechanical stresses on the stability on ~2nm insulator barrier used in the tunnel junctions.