Quantum-dot cellular automata

An introduction to the operation of quantum-dot cellular automata (QCA) is presented, along with recent experimental results. QCA is a transistorless computation paradigm that addresses the issues of device density and interc onnection. The basic building blocks of the QCA architecture,:such as AND, OR, and NOT are presented. The experimental device is a four-dot QCA-cell w ith two electrometers. The dots are metal islands, which are coupled by cap acitors and tunnel junctions. An improved design of the cell is presented i n which all four dots of the cell are coupled by tunnel junctions. A noninv asive electrometer is presented which improves the sensitivity and linearit y of dot potential measurements. The operation of this basic cell is confir med by an externally controlled polarization change of the cell. (C) 1999 A merican Vacuum Society. [S0734-2101(99)07104-3].