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].