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

Abstract

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.

Design of Pyrrole-Based Gate-Controlled Molecular Junctions Optimized for Single-Molecule Aflatoxin B1 Detection

“…Interestingly, by adequately tuning the gate voltage, , n-type (or p-type) devices can be realized by introducing the LUMO (or HOMO) molecular state into the . Furthermore, a proper engineering of the gate voltage may also enhance the ON/OFF current ratio in MolFETs, as shown in [ 29 ], and enhance the SMS sensitivity as we prove in Section 4 .…”

“…Furthermore, the possibility of synthesizing ad hoc molecules with different and peculiar transport features permits implementing promising molecular electronic components [ 16 , 17 ]. For instance, Negative Differential Resistance (NDR), which cannot be observed in current solid-state technology, can be found in [3,3]paraCyclophane (pCp)-based molecular junctions and can be exploited in designing MolFET-based circuits [ 29 , 38 ].…”

“…Molecular electrical detection has been demonstrated in various applications experimentally and theoretically [ 22 , 23 , 24 , 25 , 26 ], and significantly novel properties have been highlighted by the use of molecules in the realization of sensors [ 25 ]. In addition, possible nanoscale phenomena with exclusive conductive properties, e.g., the quantum interference [ 27 , 28 , 29 ], and successful applications in high-sensitivity sensors make it very promising for the detection of small molecules.…”

Effect of Adsorption Mechanism on Conduction in Single-Molecule Pyrrole-Based Sensor for AFB1

“…Indeed, torsion in conjugated molecules results in a certain degree of conjugation breaking, and the electrons in the π orbitals gain extra energy and angular momentum because of the orbital increased curvature. Moreover, it is known that the device portion that mainly influences the TS is the one with fewer electron states -the molecular channel [26], [32]. Therefore, an upward shift of the 8-PyDT energy levels should reflect a corresponding shift of the resonant TS peaks.…”