novel design of n-bit controllable inverter by quantum-dot cellular automata

application of quantum-dot is a promising technology for implementing digital systems at nano-scale.  quantum-dot cellular automata (qca) is a system with low power consumption and a potentially high density and regularity. also, qca supports the new devices with nanotechnology architecture. this technique works based on electron interactions inside quantum-dots leading to emergence of quantum features and decreasing the problem of future integrated circuits in terms of size. in this paper, we will successfully design, implement and simulate a new 2-input and 3-input xor gate (exclusive or gate) based on qca with the minimum delay, area and complexities. then, we will use xor gates presented in this paper, in 2-bit, 4-bit and 8-bit controllable inverter in qca. being potentially pipeline, the qca technology calculates with the maximum operating speed. we can use this controllable inverter in the n-bit adder/subtractor and reversible gate.