Food contamination by aflatoxins is an urgent global issue due to its high level of toxicity and the difficulties in limiting the diffusion. Unfortunately, current detection techniques, which mainly use biosensing, prevent the pervasive monitoring of aflatoxins throughout the agri-food chain. In this work, we investigate, through ab initio atomistic calculations, a pyrrole-based Molecular Field Effect Transistor (MolFET) as a single-molecule sensor for the amperometric detection of aflatoxins. In particular, we theoretically explain the gate-tuned current modulation from a chemical–physical perspective, and we support our insights through simulations. In addition, this work demonstrates that, for the case under consideration, the use of a suitable gate voltage permits a considerable enhancement in the sensor performance. The gating effect raises the current modulation due to aflatoxin from 100% to more than 103÷104%. In particular, the current is diminished by two orders of magnitude from the μA range to the nA range due to the presence of aflatoxin B1. Our work motivates future research efforts in miniaturized FET electrical detection for future pervasive electrical measurement of aflatoxins.
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.
NanoSheet-Gate-All-Around-FETs (NS-GAAFETs) are commonly recognized as the future technology to push the digital node scaling into the sub-3 nm range. NS-GAAFETs are expected to replace FinFETs in a few years, as they provide highly electrostatic gate control thanks to the GAA structure, with four sides of the NS channel entirely enveloped by the gate. At the same time, the NS rectangular cross-section is demonstrated to be effective in its driving strength thanks to its high saturation current, tunable through the NS width used as a design parameter. In this work, we develop a NS-GAAFET compact model and we use it to link peculiar single-device parameters to digital circuit performance. In particular, we use the well-known BSIM-CMG core solver for multigate transistors as a starting point and develop an ad hocresistive and capacitive network to model the NS-GAAFET geometrical and physical structure. Then, we employ the developed model to design and optimize a digital inverter and a five-stage ring oscillator, which we use as a performance benchmark for the NS-GAAFET technology. Through Cadence Virtuoso SPICE simulations, we investigate the digital NS-GAAFET performance for both high-performance and low-power nodes, according to the average future node present in the International Roadmap for Devices and Systems. We focus our analysis on the main different technological parameters with regard to FinFET, i.e., the inner and outer spacers. Our results highlight that in future technological nodes, the choice of alternative low-K dielectric materials for the NS spacers will assume increasing importance, being as relevant, or even more relevant, than photolithographic alignment and resolution at the sub-nm scale.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.