Quantum dot Cellular Automata (QCA) is an emerging technology for development of logic circuits based on nanotechnology, and is one of the alternative for designing high performance computing over existing CMOS-VLSI technology. QCA does not use voltage level for logic representation rather it represents binary state by polarization of electrons in the QCA Cell. Conventional logic circuits are irreversible in nature and always lead to energy dissipation. Thus extensive research is going on to design the circuits which does not dissipation the energy and hence will not loose the information. In this paper we have designed the QCA based toffoli gate and then implemented the basic logic gates with it. The circuits were successfully simulated and verified by QCA Designer tool.
