Quantum-dot cellular automaton (QCA) is a novel nanotechnology that provides a very different computation platform than traditional CMOS, in which polarization of electrons indicates the digital information. This paper demonstrates designing combinational circuits based on quantum-dot cellular automata (QCA) nanotechnology, which offers a way to implement logic and all interconnections with only one homogeneous layer of cells. In this paper, the authors have proposed a novel design of XOR gate. This model proves designing capabilities of combinational circuits that are compatible with QCA gates within nano-scale. Novel adder circuits such as half adders, full adders, which avoid the fore, mentioned noise paths, crossovers by careful clocking organization, have been proposed. Experiment results show that the performance of proposed designs is more efficient than conventional designs. The modular layouts are verified with the freely available QCA Designer tool.
 Lent, C.S., Taugaw, P.D., Porod, W. and Berstein, G.H. (1993) Quantum Cellular Automata. Nanotechnology, 4, 49. http://dx.doi.org/10.1088/0957-4484/4/1/004
 Lent, C.S., Tougaw, P.D. and Porod, W. (1994) Quantum Cellular Automata: The Physics of Computing with Arrays of Quantum Dot Molecules. Proceedings of the Workshop on Physics and Computing, Dallas, 17-20 November 1994, 5-13,
 Ahmad, P.Z., Ahmad, F. and Khan, H.A. (2014) A New F-Shaped XOR Gate and Its Implementations as Novel Adder Circuits Based Quantum-Dot Cellular Automata (QCA). IOSR Journal of Computer Engineering (IOSR-JCE), 16, 110-117.
 Vetteth, A. Walus, K. Jullien, G.A. and Dimitrov, V. (2002) Quantum Dot Cellular Automata Carry-Look-Ahead Adder and Barrel Shifter. Proceedings of the IEE Emerging Telecommunication Technologies, Dallas Tex, 2, 1-4.
 Vetteth, A., Walus, K., Dimitrov, V.S. and Jullien, G.A. (2002) Quantum-Dot Cellular Automata Carry-Look-Ahead Adder and Barrel Shifter. Proceedings of IEEE Emerging Telecommunications Tech-nologies Conference, Dallas, September 2002.
 Beigh, M.R., Mustafa, M. and Ahmad, F. (2013) Performance Evaluation of Efficient XOR Structures in Quantum-Dot Cellular Automata (QCA). Circuits and Systems, 4, 147-156.
 Lent, C.S., Liu, M. and Lu, Y.H. (2006) Bennett Clocking of Quantum-Dot Cellular Automata and the Limits Tobinary Logic Scaling. Nanotechnology, 17, 4240.
 Liu, W.Q., Srivastava, S., Lu, L., O’Neill, M. and Swartzlander, E.E. (2012) Are QCA Cryptographic Circuits Resistant to Power Analysis Attack? IEEE Transactions on Nanotechnology, 11, 1239-1251. http://dx.doi.org/10.1109/TNANO.2012.2222663
 Amlani, I., Orlov, A.O., Toth, G., Bernstein, G.H., Lent, C.S. and Snider, G.L. (1999) Digital Logic Gate Using Quantum-Dot Cellular Automata. Science, 284, 289-291.
 Lent, C.S. and Tougaw, P.D. (1997) A Device Architecture for Computing with Quantum Dots. Proceedings of the IEEE, 85, 541-557. http://dx.doi.org/10.1109/5.573740
 Karthigai lakshmi, S. and Athisha, G. (2010) Efficient Design of Logical Structures and Functions Using Nanotechnology Based Quantum Dot Cellular Automata Design. International Journal of Computer Applications (0975-8887), 3, 35.
 Teja, V.C., Polisetti, S. and Santhosh, K. (2008) QCA Based Multiplexing of 16 Arithmetic & Logical Sub-System a Paradigm for Nano Computing. 3rd Annual IEEE-International Conference on Nano/Micro Engineering Molecular System, Sanya, 6-9 January 2008, 758-763.
 Choi, Myungsu and Choi, Minsu (2008) Scalability of Globally Asynchronous QCA (Quantum-Dot Cellular Automata) Adder Design. Journal of Electronic Testing, 24, 313-320.
 Hanninen, I. and Taka, J. (2008) Arithmetic Design on Quantum-Dot Cellular Automata Nanotechnology. Workshop on Embedded Computer Systems Architectures, Modeling, and Simulation SAMOS, Samos, 21-24 July 2008, 43-52.
 Lakshmi, S.K. and Athisha, G. (2011) Design and Analysis of Adders Using Nanotechnology Based Quantum Dot Cellular Automata. Journal of Computer Science, 7, 1072-1079.
 Tougaw, P. and Lent, C. (1994) Logical Devices Implemented Using Quantum Cellular Automata. Journal of Applied Physics, 75, 1818-1825. http://dx.doi.org/10.1063/1.356375
 Santra, S. and Roy, U. (2014) Design and Implementation of Quantum Cellular Au-tomata Based Novel Adder Circuits. World Academy of Science, Engineering, and Technology. International Journal of Computer, Information Science and Engineering, 8.
 Walus, K., Schulaf, G. and Jullien, G.A. (2004) Circuit Design Based on Majority Gates for Application with Quantum Dotcellular Automata. Proceedings of the IEEE Conference on Nanotechnology, 4, 1350-1356.