In a vastly rapid progress of very large scale integration (VLSI) archetype, it is the requirement of moment to attain a consistent model with swifter functioning speed and low power utilization. Quantum-dot Cellular Automata (QCA) is an inimitable transistorless computation approach that is based on semiconductor substantial and a substitute for customary CMOS and VLSI archetype at nanoscale point which comprises a better switching frequency, enhanced scale integration and small extent. In the design of digital logic, a comparator is the essential forming component which implements the resemblance of two numbers and a binary full adder is a major entity in digital logic systems. This paper deals with an expanded layout of reversible 1-bit comparator and proficient full adder without wire-crossing in QCA. The proposed layouts are significantly declined in terms of area and cell complexity, assessed to other layouts and clock cycle is retained at least. Quantum costs of the proposed circuits are estimated and compared, that shows the proposed QCA layouts have lesser quantum cost equated to regular designs and the energy depletion by the circuits endorses the view of QCA nano-circuit attending as a substitute level for the completion of reversible computing. Under thermal unpredictability, the constancy of the proposed designs is evaluated which show the operating efficacy of the designs. The simulation outcomes in QCADesigner tool approve that the presented designs performs properly and can be operated as an extreme performing design in QCA technology.

Quantum-dot cellular automata (QCA) is the beginning of novel technology and is capable of an appropriate substitute for orthodox semiconductor transistor technology in the nanoscale extent. A competent adder and subtractor circuit can perform a substantial function in devising arithmetic circuits. The future age of digital techniques will exercise QCA as preferred nanotechnology. The QCA computational procedures will be simplified with an effective full adder and subtractor circuit. The deficiencies of variations and assembly still endure as a setback in QCA based outlines, and being capricious and inclined to error is the limitation of these circuits. In this study, a new full adder and subtractor design using unique 3-input XOR gate with cells redundancy is proposed. This designs can be utilized to form different expedient QCA layouts. The structures are formed in a single layer deprived of cross-wiring. Besides, this study is directed to the analysis of the functionality and energy depletion possessions of the outlined full adder and subtractor circuits. For the first time, QCADesigner-Energy (QD-E) version 2.0.3 tool is utilized to find the overall depleted energy. The attained effects with QCADesigner have verified that the outlined design has enhanced functioning in terms of intricacy, extent, and latency in contrast to the earlier designs. Moreover, the redundant form of full adder and subtractor has uncomplicated and robust arrangement competing typical styles.

Quantum-dot cellular automata (QCA) as nanotechnology is a pledging contestant that has incredible prospective to substitute complementary metal-oxide-semiconductor (CMOS) because of its superior structures such as intensely high device thickness, minimal power depletion with rapid operation momentum. In this study, the dataset of average output polarization (AOP) for fundamental reversible logic circuits is organized as presented in (Abdullah-Al-Shafi and Bahar, 2017; Bahar et al., 2016; Abdullah-Al-Shafi et al., 2015; Abdullah-Al-Shafi, 2016) [1-4]. QCADesigner version 2.0.3 has been utilized to survey the AOP of reversible circuits at separate temperature point in Kelvin (K) unit.