Enhancing the On/Off Current Ratio in Single-Molecule FET via Destructive Quantum Interference

We investigate through atomistic calculation the electronic structure and transport properties of 3-phenylethynylene (OPE3), 7-phenylvynylene (OPV7), and [3,3]paraCyclophane(pCp)-based molecules. We reveal and analyze the Destructive Quantum Interference (DQI) phenomenon for the pCp single-molecule junction. The provided explanation of DQI via the dominant concurrence of inter-orbital and intra-orbital interference may support DQI engineering through the chemical synthesis of ad hoc molecular channel. Furthermore, we propose a Back gate Biasing-based method for the ON/OFF CUrrent Ratio Enhancement of the single-molecule Field-Effect transistor via the control of DQI (BBB-CURE-DQI). As an important outcome of the proposed method, an ON/OFF current ratio of 10(3) is achieved for pCp single-molecule FET. This value is orders of magnitude larger than typical values presented in the literature. The benefit of the DQI and the effectiveness of the BBB-CURE-DQI method are finally demonstrated at the circuital level by SPICE simulations of digital inverters implemented with the investigated molecules. Our analysis and results motivate the importance of future research investment for DQI manipulation via chemical synthesis and successive control to enable single-molecule FET-based nanocomputing applications.