Conventional silicon microelectronics has undergone relentless miniaturisation over the last decades, leading to significant improvements in processing speed and power. Miniaturisation, however, is near its limits and scientists have been exploring other promising avenues. Electronic components comprised of molecular building blocks can help overcome problems related to the miniaturisation of conventional silicon devices. In molecular-based devices, individual molecules can replace wires, resistors and transistors. Research in this emerging field is, however, fragmented. To help overcome this, the EU-funded project MEKIMI helped establish a new methodology for the design of molecular devices, nanocircuits and nanoexperiments that could fill the gap between micro and molecular electronics in the near future. Researchers focused on a particular molecular electronics device called a molecular quantum-dot cellular automata wire (MQCAW) that can be used as a precursor of other molecular systems to come. They studied the bis-ferrocene molecule to analyse its potential for quickly transmitting electrons, a critical property for molecular electronics, using ab initio simulations. Results proved the molecule’s ability to reliably propagate information for nanocomputation, demonstrating high carrier mobility when oxidised and good behaviour to the clock signal. The team then closely examined the behaviour of bis-ferrocene deposited on a real gold substrate. Results are essential to derive constraints on surface quality when fabricating the MQCAW sub-elements. MQCAW subsystems were simulated to understand the possible structures that might influence the molecule’s capability for write-in and/or clocking. Another research strand focused on developing a method to fabricate the electrodes hosting the molecule and forcing an input field and an external multi-phase clock. Researchers conceived a completely new technique to fabricate nanometre-sized nanowires, overcoming the current limit in resolution of up-to-date fabrication methods. The fabricated test structure constitutes a fundamental element for other more complex MQCAW structures and for any molecular-based device requiring very narrow electrodes. The combination of several simulation tools for investigating the molecular self-assembly and the relation between the molecular behaviour and the control electrodes, implemented for the first time, will have a disruptive effect on the way in which not only MQCAW but also other molecular structures will be analysed. The holistic modelling approach of the MQCAW sets a new paradigm regarding the conventional way of simulating molecular electronics.
Molecular electronics, microelectronics, MEKIMI, molecular quantum-dot cellular automata wire, nanocomputation