Title :
Measurement of effective drift velocities of electrons and holes in shallow multiple-quantum-well p-i-n modulators
Author :
Yang, Ching-Mei ; Canoglu, Ergun ; Garmire, Elsa ; Goossen, Keith W. ; Cunningham, J.E. ; Jan, W.Y.
Author_Institution :
Center for Laser Studies, Univ. of Southern California, Los Angeles, CA, USA
fDate :
9/1/1997 12:00:00 AM
Abstract :
We present results on carrier transport in shallow multiple-quantum-well GaAs-AlxGa1-xAs p-i-n diodes (x=0.02, 0.04, 0.08) at various bias voltages. We show that only carrier drift and enhanced diffusion dominate response times of these devices. We also emphasize that the drift of holes plays different roles in determining the response times: at low bias, the slow drift of holes adds to enhanced diffusion, slowing down the decay-times; at high bias, the drift time of holes can be comparable to the time of electrons and contribute to the rise-times. From picosecond time-resolved pump/probe electroabsorption measurements, we obtain the drift times, effective drift velocities, and effective mobilities of electrons and holes. The effective drift velocities (especially for holes) appear rather insensitive to the Al concentration in the barriers
Keywords :
III-V semiconductors; aluminium compounds; carrier mobility; electro-optical modulation; electroabsorption; gallium arsenide; high-speed optical techniques; optical pumping; optical testing; p-i-n photodiodes; semiconductor quantum wells; Al concentration; GaAs-AlxGa1-xAs p-i-n diodes; GaAs-AlGaAs; bias voltages; carrier transport; effective drift velocities; electrons; enhanced diffusion; holes; picosecond time-resolved pump/probe electroabsorption measurements; response times; shallow multiple-quantum-well p-i-n modulators; Charge carrier processes; Delay; Electrodes; Electron mobility; Optical modulation; P-i-n diodes; Probes; Quantum well devices; Velocity measurement; Voltage;
Journal_Title :
Quantum Electronics, IEEE Journal of
