A quantum-dot cellular automata shift register

Presents a more advanced device in the family of clocked QCA systems - a two cell shift register. The device consists of two capacitively coupled QCA latches The QCA latch consists of three micron-sized aluminum islands, or dots separated by tunnel junctions. Multiple tunnel junctions are used between dots to increase the charge retention time of the latches. Two single-electron electrometers measure the state of the shift register.