A major challenge in molecular electronics is to attach electrodes to single molecules in a reproducible manner to make molecular junctions that can be operated as transistors. Several attempts have been made to attach electrodes to proteins, but these devices have been unstable. Here, we show that self-assembly can be used to fabricate, in a highly reproducible manner, molecular junctions in which an antibody molecule (immunoglobulin G) binds to two gold nanoparticles, which in turn are connected to source and drain electrodes. We also demonstrate effective gating of the devices with an applied voltage, and show that the charge transport characteristics of these protein transistors are caused by conformational changes in the antibody. However, because of limitations in current technology, the achievement of these goals is very challeng- ing. Although, some isolated examples of such devices and architectures have been demonstrated, they exhibit only moderate or limited performance, or are constructed via sophisticated multistep methodologies. In this publication Mentovich and his team suggest and demonstrate a universal method in which a new type of nanometer-sized, ambipolar, vertical molecular transistor is fabricated in parallel fashion. This centralgate molecular vertical transistor (C-Gate MolVeT) is fabricated by a combination of conventional microlithography techniques and self-assembly methods. The general fabrication methodology of the C-Gate MolVeT allows the process to be adapted for various materials and systems.In this design, the nanometer channel length is determined by a protein-based self-assembled monolayer composed of bovine serum albumin protein, that is sandwiched between source and drain electrodes inside a microcavity, while a centered oxidized-metal-electrode column inside the cavity serves as the gate electrode. The results showed a transistor fully operational, that can be made with lithography thechniques, they messured the gate effect, and demonstrated the characteristic transistor curves when variating the voltage in the drain terminal.
The full article can be found in nanoletters: