Experimental demonstration of a latch in clocked quantum-dot cellular automata

We present an experimental demonstration of a latch in a clocked quantum-do t cellular automata (QCA) device. The device consists of three floating mic ron-size metal dots, connected in series by multiple tunnel junctions and c ontrolled by capacitively coupled gates. The middle dot acts as an adjustab le barrier to control single-electron tunneling between end dots. The posit ion of a switching electron in the half cell is detected by a single-electr on electrometer. We demonstrate "latching" of a single electron in the end dots controlled by the gate connected to the middle dot. This ability to lo ck an electron in a controllable way enables pipelining, power gain and red uced power dissipation in QCA arrays. (C) 2001 American Institute of Physic s.