Design and Implementation of Novel Efficient Full Adder/Subtractor Circuits Based on Quantum-Dot Cellular Automata Technology

One of the emerging technologies at the nanoscale level is the Quantum-Dot Cellular Automata (QCA) technology, which is a potential alternative to conventional CMOS technology due to its high speed, low power consumption, low latency, and possible implementation at the atomic and molecular levels. Adders are one of the most basic digital computing circuits and one of the main building blocks of VLSI systems, such as various microprocessors and processors. Many research studies have been focusing on computable digital computing circuits. The design of a Full Adder/Subtractor (FA/S), a composite and computing circuit, performing both the addition and the subtraction processes, is of particular importance. This paper implements three new Full Adder/Subtractor circuits with the lowest number of cells, lowest area, lowest latency, and a coplanar (single-layer) circuit design, as was shown by comparing the results obtained with those of the best previous works on this topic.