Abstract
A three-dimensional (3-D) QCA architecture is proposed in this express. The design of a 3-D quantum-dot cellular automata (QCA) full adder based on 3-D inverters and majority gates is presented and compared with its 2-D counterparts. The 3-D adder uses over 46% less cells and occupies 40% less area compared with the best 2-D design. The proposed 3-D QCA architecture offers an additional dimension for computation, which is not available in current CMOS technology.