Robust and efficient QCA cell-based nanostructures of elementary reversible logic gates

Increasing device density and reducing energy consumption are challenging issues in integrated nanoscale circuits. Reversible logic in quantum-dot cellular automata (QCA) nanotechnology is emerging as a promising candidate to overcome these issues and to introduce new computation paradigms with unique features like nanoscale feature size and ultra-low power dissipation. For the first time, QCA cell-based designs of reversible Feynman, Toffoli, Fredkin, and Peres gates are presented in this paper. These elementary gates are usually used in the synthesis of reversible circuits. The proposed layouts utilize electrostatic interactions between cells within QCA configurations to perform desired functions. All the robust designs are evaluated in terms of hardware complexity and power dissipation using QCADesigner and QCAPro simulation tools. The efficient QCA layouts of proposed gates have notable improvements as compared to the existing ones in terms of gate delay, cell count, area occupation, quantum cost, leakage energy, and switching energy. As a result, the proposed elementary gates via QCA cell level-based design are good candidates for building and developing high-level nanoelectronic reversible circuits.