Nanomaterial-based ultra-low-energy device design is one of the prime research areas in nanoscale computation. In ‘more-than-Moore’ technological trends, new device designs with quantum dot nanostructure have become an emerging domain of research. Various quantum dot-based devices, especially quantum dot cellular automata, have been designed both experimentally and by simulation. These quantum devices operate solely on the principle of charge localisation, which accounts for their high speed and ultra-low energy consumption. Quantum dots have an innate ability to confine electrons. As a result, quantum dot formation in a device is highly desirable in order to design quantum devices. Quantum dot implementation with interfacing indium phosphide (InP)–gallium arsenide (GaAs)–indium phosphide nanostructure and quantum dot formation within the redox centres of an allyl molecule are reported in this paper. The formation of the quantum dot is confirmed by the density-of-state studies conducted by the density functional theory calculation on the proposed nanostructures. The possibility of a new device design with two polarised states, namely ‘state x’ and ‘state x −1’, is also explored. Further, outlined in this paper is the design of quantum devices using Python coding, which makes it easier for a programmer to design any kind of complex nanostructure for nanoscale computation.

In this paper, fan-out constraints are demonstrated for robust and reliable quantum dot cellular automata (QCA) device design. These QCA devices can be used to implement large and complex circuits without affecting the expected result. The tile-based QCA nanostructures are more robust and reliable. In this paper, the Hopfield artificial neural network (HANN) model is proposed to find out the robustness and the reliability of QCA nanostructure devices. This proposed HANN model demonstrates that the tile nanostructures of QCA devices are more robust and reliable for driving multiple fan-outs from a particular QCA device. The Kink energy was used in computing the polarity when considering multiple fan-outs. The tile three-input majority voter, the triple fan-out butterfly tile, the multiple fan-out tile structure and the five-input majority voter are the most robust and reliable structures for solving the fan-out problem in QCA and are described in this paper by the proposed HANN model.