A Novel Design of Reversible Toffoli Gate in Quantum-Dot Cellular Automata

It has always happened in human history that when we thought that things were perfect and nothing better can be done or the thing will suffice us forever some problems unforeseen came up same is the case with CMOS (Complementary Metal Oxide Semiconductors), now researchers are looking beyond CMOS to QCA (Quantum-dot Cellular Automata), a technique which was formulated out of the applications of quantum mechanics. Talking about QCA it is an ingenious technique to fabricate new generation processors and other combinational and sequential circuits. The eye-catching and commercially useful properties of QCA that set it apart from any other technique is its extremely low power consumption in meV, small size going up to nanometer scale, high frequency operation (THz) and elimination of short channel effect. Quantum computing aims to use QCA as the building block for upcoming devices. In this paper, we have improved on the design of the Toffoli gate which is a reversible universal gate. We have successfully improved it on parameters such as cell count by more than 20%, total area by 34%, cell area by 29% and we have maintained latency and complexity as the previous optimal designs even by having less cell count. These improvements will help reduce the size of the chip and reduce power dissipation and thus improve efficiency and be compliant with the ever-increasing computational ability and downscaling requirements.