Design of Optimized Quantum-dot Cellular Automata RS Flip Flops

Document Type : Research Paper


Electrical Engineering Department, Kermanshah University of Technology, Kermanshah, Iran


   Complementary metal-oxide semiconductor (CMOS) technology has been the industry standard to implement Very Large Scale Integrated (VLSI) devices for the last two decades. Due to the consequences of miniaturization of such devices (i.e. increasing switching speeds, increasing complexity and decreasing power consumption), it is essential to replace them with a new technology. Quantum-dot cellular automata (QCA) is one of the alternative technologies proposed as a replacement solution to the fundamental limits of CMOS technology. QCA has the potential to be one of the features promising nanotechnologies because of its higher speed, smaller size and lower power consumption in comparison with transistor-based technology. This work proposes optimized QCA RS (Reset Set) flip flops. The proposed structures are simulated and validated using QCADesigner software. In comparison with the previous works the proposed QCA RS flip flops require the minimum number of cells, area and delay. Also, in comparison with CMOS technology our QCA designs are more efficient in terms of area, delay and frequency. Therefore, these structures can be used to design nanoscale circuits.


  1. Walus, K., Wang, W., Julliaen, G.A. (2004). “Quantum Cellular Automata Adders”, IEEE Nanotechnology conf., 3: 461-463.
  2. Lent, CS., Tougaw, PD., Porod, W. (1994). “Quantum Cellular Automata: the Physics of Computing With Arrays of Quantum Dot Molecules”, IEEE Computer Society Press, Silver Spring, 5-13.
  3. Walus, K. (2003). “Computer Architecture structure for Quantum Cellular Automata”, IEEE Nanotechnology conf. 3: 1435-1439.
  4. Walus, K., Schulaf, GA. (2004). “Circuit Design Based on Majority Gates for Application with Quantum Dot Cellular Automata“, IEEE Nanotechnology conf., 4: 1350-135.
  5. Momenzadeh, M., Huang, J., Lombardi, F., (2005). “Defect Characterization and Tolerance of QCA Sequential Devices and Circuits“, IEEE International Symposium on Defect and Fault Tolerance in VLSI Systems, 199-207.
  6. Huang, J., Momenzadeh, M., Lombardi, F., (2007). “Design of Sequential Circuits by Quantum Dot Cellular Automata“, Microelectronic Journal. 38: 525-537.
  7. Dallaki, H., Mehran, M., (2015). “Novel Subtractor Design Based on Quantum-Dot Cellular Automata (QCA) Nanotechnology“, Int. J. Nanosci. Nanotechnol. 11(4): 257-262.
  8. Safavi, A., Mosleh, M., (2016). “Presenting a New Efficient QCA Full Adder Based on Suggested MV32 Gate“, Int. J. Nanosci. Nanotechnol. 12(1): 55-69.
  9. Kianpour1, M., Sabbaghi-Nadooshan, R., (2014). “Novel Design of n-bit Controllable Inverter by Quantum-dot Cellular Automata“, Int. J. Nanosci. Nanotechnol. 10(2): 117-126.

10. Nath Sasamal, T., Singh, A.K., Mohan, A., (2016). “An optimal design of full adder based on 5-input majority gate in coplanar quantum-dot cellular automata“, Optik-International Journal for Light and Electron Optics. 127(20): 8576-8591.

11. Rao, N.G., Srikanth, P.C., Sharan, P., (2016). “A novel quantum dot cellular automata for 4-bit code converters“, Optik-International Journal for Light and Electron Optics. 127(10): 4246-4249.

12. Heikalabad, S.R., Navin, A.H., Hosseinzadeh, M., (2016). “Content addressable memory cell in quantum-dot cellular automata“, Microelectronic Engineering. 163: 140-150.

13. Mohammadi, M., Mohammadi, M., Gorgin, S., (2016). “An efficient design of full adder in quantum-dot cellular automata (QCA) technology“, Microelectronics Journal. 50: 35-43.

14., (2016).

15. Jagarlamudi, HS., Saha, M., Jagarlamudi, PK., (2011). “Quantum Dot Cellular Automata Based Effective Design of Combinational and Sequential Logical Structures“, World Academy of Science, Engineering and Technology. 60: 671-675.

16. Vetteth, A., Walus, K., Dimitrov, VS., Jullien, GA., (2003). “Quantum-dot Cellular Automata of flip-flops”, The National Conference on Communications (NCC). 368-372.

17. Choi, M., (2005). “A study on a Quantum-dot Cellular Automata based asynchronous circuit design“, M.S., Oklahoma State University, 49: 1431653.