Quantum-well charge-coupled devices for charge-coupled device-addressed multiple-quantum-well spatial light modulators

We have demonstrated a new type of GaAs/AlGaAs charge-coupled device (CCD) in which the charge is confined to a quantum-well channel. The MBE-grown quantum-well CCD (designated QWCCD) has a channel consisting of a 140 Å GaAs layer clad on both sides by AlGaAs layers. This structure was grown on a multiple-quantum-well (MQW) structure consisting of 60 periods of GaAs and AlGaAs layers of about 100 Å thickness each. Large optical modulation effects involving quantum-confined excitons were observed in the MQW structure when a bias was applied perpendicular to the plane of the layers. The combination of QWCCD and MQW structures has promise as a high-speed spatial light modulator for applications in optical signal processing.