It is expected that the role of complementary metal–oxide–semiconductor (CMOS) as the dominant technology for very-large-scale integrated circuits will encounter serious problems in the near future due to limitations such as short channel effects, doping fluctuations, and increasingly difficult and expensive lithography at nanoscale. The projected expectations of diminished device density and performance and increased power consumption encourage investigation of radically different technologies. Nanotechnology, especially quantum-dot cellular automata (QCA) provides new possibilities for computing owing to its unique properties . QCA relies on a fresh physical phenomena (Coulombic interaction), and its logic states are not stored as voltage levels, but rather as the position of individual electrons. Even though the physical implementation of devices is still being developed, it is appropriate to investigate QCA circuit architecture.