||J. A. Cavailles, D. A. B. Miller, J. E.
Cunningham, P. Li Kam Wa, A. Miller "Simultaneous measurements of electron and hole
sweep-out from quantum wells and modeling of photoinduced field screening dynamics"
IEEE J. of Quantum Electronics, 28, 2486-2497 (1992).
Electron and hole
escape times from a GaAs-AlGaAs quantum well in an electric field at room temperature are
measured by picosecond optical pump-probe techniques on samples containing a single
quantum well in a waveguide. The use of a single well avoids multiple well transport and
resonant tunneling effects. Carriers excited in the quantum well by the pump beam result
in a transient bleaching signal from excitonic saturation, and, as they leave the well, a
transient electroabsorption signal because the movement of charge partially screens the
electric field. Both processes are modeled, including important electrical equilibration
processes of the sample as a whole. This modeling and the use of two samples with
asymmetric barrier heights allows the measurement of the electron and hole emission as a
function of applied electric field. Preliminary analysis suggests that the emission
mechanism is thermionic rather than by tunneling, but the results are not well explained
by conventional thermionic emission models
Full text available for