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The Development of an Improved Design and Simulation Tool for Atomic Silicon Quantum Dot Cellular Automata (QCA) Circuits

Principal Supervisor (Director of Studies): Dr G. Edwards, Electronic & Electrical Engineering Subject Group, Department of Computer Science and Electronic & Electrical Engineering

Second Supervisor: Dr G. Spink, Department of Chemical Engineering

Suitable Background for Prospective Student: 

Upper Second Class in Undergraduate Degree (BSc Physics, BEng Electrical & Electronic Engineering, BSc Applied Mathematics)

Project Description:

Recent experiments in scanning probe microscopy have shown that the creation and erasure of Silicon (Si) dangling bonds (DBs) on the hydrogen passivated Si surface, can be carried out reproducibly at room temperature. The DBs can be considered as zero - dimensional quantum dots (QDs) with energies that sit withing the Si bulk bandgap. These DBs have at most two occupying electrons and the total number of electrons for a spatial configuration, of a set of these DB QDs, in close proximity, is determined by the electrostatic interaction. By controlling the spatial location of an array of DB QDs, logic gates can be created, allowing a brand new implementation platform for the Quantum Dot Cellular Automata (QCA) paradigm (Lent, Liu, & Lu, 2006). The Walrus group has developed the Silicon Quantum Atomic Designer (SiQAD) Computer Aided Design (CAD) tool for the design and simulation of DB QD circuits. SiQAD allows the rapid prototyping of nano-electronic computer circuits, to give insight whether the design will function properly, before being actually fabricated. The PhD topic for this project, is to enhance the SiQAD simulation tool by improving the treatment of the underlying physics describing the formation of the DBs, covering both the energetics and the hopping dynamics aspects. The PhD student needs a strong aptitude for both mathematical modelling and object - oriented programming skills in C++.


Hang Ng, S. S., Retallick, J., Chiu, H. N., Lupoiu, R., Livadaru, L., Huff, T., . . . Walus, K. (2020). SiQAD: A Design and Simulation Tool for Atomic. IEEE Transactions on Nanotechnology, 19, 137.

Lent, C. S., Liu, M., & Lu, Y. (2006). Bennett clocking of quantum-dot cellular automata and the limits to binary logic. Nanotechnology, 17, 4240.

Contact Information:

For self-funding PhD candidates interesting in the above project and the research area of nano-electronics in general, contact Dr Gerard Edwards.

Dr Gerard Edwards
Tel: 01244 512314