Area Efficient Multilayer Designs of XOR Gate Using Quantum Dot Cellular Automata

Quantum dot cellular automata is a well known technology which is a prospective paradigm for quantum computing. It is evident that QCA is going to be an alternative for CMOS technology for future circuits due to its property of low power, high speed and high density. Numerous digital circuits employ exclusive OR functions for executing arithmetic, error detecting or correcting operations. Thus, design of XOR gate is crucial with regard to cost efficiency and modular design competency. In QCA circuits, improved cost efficiency can be attained by minimizing one of the important parameters i.e. area of the QCA layout. Multilayer topology works successfully to reduce area and enhance the density of large circuits. This paper targets the design of multilayer XOR gate with improved cost function. Four possible QCA structures of XOR gate are proposed here, using multilayer topology. Multilayer topology assures area efficient structures. Moreover, the multiplexer and half adder circuits are presented here, using the most efficient proposed XOR design.