Relaxation processes of hot holes in germanium and

Authors: Thomas Elsaesser Andrea Lohner Michael Woerner

Publish Date: 1992

Volume: , Issue: , Pages: 131-144

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Abstract

Relaxation processes of holes in ptype Ge and GaAs are investigated with picosecond infrared pulses in the wavelength range from 08 to 12 μm The transient intervalence band absorption of Ge studied in spectrally and temporally resolved measurements reveals subpicosecond carriercarrier and intervalence band scattering of the excited holes followed by the picosecond cooling of hot heavy holes via emission of optical phonons Photogenerated nonequilibrium splitoff holes give rise to a shortlived population inversion between the splitoff and the light hole band resulting in a transient gain around 260 meV In ptype GaAs ultrafast recombination of holes with shallow acceptors is directly observed for the first time Carrier capture occurs on a time scale of several tens of picoseconds following a nonexponential kinetics Emission of longitudinaloptical phonons by free holes is found to be the dominant mechanism of recombination directly populating the acceptor ground state

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