  We present a method of forming and controlling large arrays of gate-defined
quantum devices. The method uses a novel, on-chip, multiplexed charge-locking
system and helps to overcome the restraints imposed by the number of wires
available in cryostat measurement systems. Two device innovations are
introduced. Firstly, a multiplexer design which utilises split gates to allow
the multiplexer to divide three or more ways at each branch. Secondly we
describe a device architecture that utilises a multiplexer-type scheme to lock
charge onto gate electrodes. The design allows access to and control of gates
whose total number exceeds that of the available electrical contacts and
enables the formation, modulation and measurement of large arrays of quantum
devices. We fabricate devices utilising these innovations on n-type GaAs/AlGaAs
substrates and investigate the stability of the charge locked on to the gates.
Proof-of-concept is shown by measurement of the Coulomb blockade peaks of a
single quantum dot formed by a floating gate in the device. The floating gate
is seen to drift by approximately one Coulomb oscillation per hour.
