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Free-electron laser study of the nonlinear magnetophotoconductivity in n -GaAs

1988; American Institute of Physics; Volume: 52; Issue: 3 Linguagem: Inglês

10.1063/1.99506

1520-8842

J. Kaminski, J. Spector, W. Prettl, M. Weispfenning,

Electron and X-Ray Spectroscopy Techniques

The University of California at Santa Barbara free-electron laser was used to investigate the kinetics of electrons bound to shallow donors in n-GaAs by saturation spectroscopy. The resonant photothermal conductivity arising from 1s–2p+ shallow donor excitations in a magnetic field was measured at intensities greatly exceeding that of earlier investigations and saturation of bound-to-free photoionization transitions was achieved. The impurity resonance photoconductive signal shows a distinct intensity dependence caused by competing bound-to-free transitions which saturate differently. This permits a more detailed evaluation of the electron recombination kinetics than was previously possible, yielding the ionization probability of the 2p+ state, the transition time of electrons from the 2p+ level to the gound state, and the recombination time of free carriers.