A New Nano-Scale and Energy-Optimized Reversible Digital Circuit Based on Quantum Technology

A nano-scale quantum-dot cellular automaton (QCA) is one of the most promising replacements for CMOS technology. Despite the potential advantages of this technology, QCA circuits are frequently plagued by numerous forms of manufacturing faults (such as a missing cell, extra cell, displacement cell, and rotated cell), making them prone to failure. As a result, in QCA technology, the design of reversible circuits has received much attention. Reversible circuits are resistant to many kinds of faults due to their inherent properties and have the possibility of data reversibility, which is important. Therefore, this research proposes a new reversible gate, followed by a new 3 × 3 reversible gate. The proposed structure does not need rotated cells and only uses one layer, increasing the design’s manufacturability. QCADesigner-E and the Euler method on coherence vector (w/energy) are employed to simulate the proposed structure. The 3 × 3 reversible circuit consists of 21 cells that take up just 0.046 µm2. Compared to the existing QCA-based single-layer reversible circuit, the proposed reversible circuit minimizes cell count, area, and delay. Furthermore, the energy consumption is studied, confirming the optimal energy consumption pattern in the proposed circuit. The proposed reversible 3 × 3 circuit dissipates average energy of 1.36 (eV) and overall energy of 1.49 (eV). Finally, the quantum cost for implementing the reversible circuits indicates a lower value than that of all the other examined circuits.