Carrier collection efficiency effects and improvements of electroabsorption devices with different barrier structures

Self-electrooptic effect devices (SEEDs) with both thick (60 Å) and thin (35 Å) quantum-well barriers were studied experimentally. Relevant device properties including responsivity, carrier collection efficiency, switching, and optical bistability behavior are compared. SEED modulator photocurrent and reflectivity data are analyzed and shown to predict S-SEED behavior. A simple yet powerful optical technique for measuring the light utilization efficiency and the carrier collection efficiency η is described and used to compare different device mesa sizes and barrier structures. The effects of η on device performance are expounded. For thin-barrier SEEDs, η is substantially improved, approaching 100%, even at bias voltages approaching zero and for small device structures