**6. Conclusions**

The development of nano-scale quantum dot cellular automata (QCA) has been drivern by the immense need for high performance and energy-efficient computational systems. The present work proposed a new three-input QCA XOR gate consisting of 12 cells with an occupied space of 0.01 μm2 . Hence, the proposed gate is superior than the existing XOR structures in literature. The designed gate dissipate less energy, has been verified using the QCAPro tool. Simulation results have been shown that the suggested gate is suitable techniques to implement efficient logic circuits for QCA.. In the future, we will strive to explore and construct more excellent QCA based-design in order to provide basic module for the larger scale arithmetic operation circuits.

*Quantum Computing and Communications*
