An introduction to the operation of quantum-dot cellular automata is presen
ted, along with recent experimental results. Quantum-dot cellular automata
(QCA) is a transistorless computation paradigm that addresses the issues of
device density and interconnection. The basic building blocks of the QCA a
rchitecture, such as AND, OR, and NOT are presented. The experimental devic
e is a four-dot QCA cell with two electrometers. The dots are metal islands
, which are coupled by capacitors and tunnel junctions.