Graphene has long been considered a revolutionary material for the field of electronics due to its remarkable set of electronic properties, standing as a very promising candidate for the post-silicon era. However, it is not just a silicon replacement, but rather an enabling material for different computing paradigms. In this work, we investigate the use of graphene in devices and circuits that are employed for the realisation of computing architectures and systems. More specifically, we focus on impactful key applications such as conventional computing and Boolean logic, high-radix computing and multi-valued logic, memristive devices and in-memory-computing, neuromorphic applications, quantum computing and photonics. Additionally, taking into consideration the state-of-the-art as well as the existing graphene-related challenges that are still present, this work attempts to assess the possible future development of graphene-based devices, circuits and systems in each of the aforementioned fields and to propose a coarse yet directive roadmap for the material's future in computing architectures.

Quantum-dot Cellular Automata (QCA) provide very high scale integration potential, very high switching frequency, and have extremely low power demands, which make the QCA technology quite attractive for the design and implementation of large-scale, high-performance nanoelectronic circuits. However, state-of-the-art QCA circuit designs were not derived by following a set of universal design rules, as is the case of CMOS circuits, and, as a result, it is either impossible or very difficult to combine QCA circuit blocks in effective large-scale circuits. In this paper, we introduce a novel automated design methodology, which builds upon a QCA specific universal design rules set. The proposed methodology assumes the availability of a generic QCA crossbar architecture and provides the means to customize it in order to implement any given logic function. The programming principles and the flow of the proposed automated design tool for crossbar QCA circuits are described analytically and we apply the proposed automated design method for the design of both combinatorial and sequential circuits. The obtained designs demonstrate that the proposed method is functional, easy to use, and provides the desired QCA circuit design unification.