Vertical molecular transistors: a new strategy towards practical quantum devices

Considerable effort has been dedicated to improving molecular devices since they were initially proposed by Aviram and Ratner in 1974. Organic molecules are small and have discrete molecular orbitals. These features can facilitate fascinating quantum transport phenomena, such as single-carrier tunneling, resonant tunneling, and quantum interference. The effective gate modulation of these quantum transport phenomena holds the promise of realizing a new computing architecture that differs from that of current Si electronics. In this article, we review the recent research progress on molecular transistors, specifically vertical molecular transistors (VMTs). First, we discuss the benefits of VMTs for future molecular-scale transistors compared with the currently dominant lateral molecular transistors. Subsequently, we describe representative examples of VMTs, where single molecules, self-assembled monolayers, and isolated molecules are used as transistor channels. Finally, we present our conclusions and perspectives about the use of VMTs for attractive quantum devices.