Quantum-Dot Cellular Automata (QCA) Nanotechnology for Next-Generation Systems

Quantum-dot cellular automata (QCA) is one of the new promising nanotechnologies. QCA can replace the complementary metal-oxide semiconductor (CMOS) technology in an ultra-nano-scale regime. Short-channel effects limit the use of CMOS in the ultra-nano-scale regime. QCA circuits are fast, highly dense, and dissipate less energy. This chapter presents the basics of QCA nanotechnology, focusing on digital circuit design. QCA digital circuits consume low power along with high cell density. In digital circuits, an adder performs addition and is widely used in different applications. Various existing full adders using QCA nanotechnology are extensively discussed and compared using the QCA designer tool. QCA full adders have been designed using different approaches, which gives an idea to design an efficient digital complex circuit.