Coherent dynamics of exciton wavepackets in semiconductor heterostructures
J Feldmann; M Koch; E O Gobel; F Jahnke; T Meier; W Schafer; P Thomas; S W Koch; H Nickel; S Luttgen; W Stolz; J Feldmann; Dept. of Phys., Philipps-Univ., Marburg, Germany; M Koch; Dept. of Phys., Philipps-Univ., Marburg, Germany; E O Gobel; Dept. of Phys., Philipps-Univ., Marburg, Germany; F Jahnke; Dept. of Phys., Philipps-Univ., Marburg, Germany; T Meier; Dept. of Phys., Philipps-Univ., Marburg, Germany; W Schafer; Dept. of Phys., Philipps-Univ., Marburg, Germany; P Thomas; Dept. of Phys., Philipps-Univ., Marburg, Germany; S W Koch; Dept. of Phys., Philipps-Univ., Marburg, Germany; H Nickel; Dept. of Phys., Philipps-Univ., Marburg, Germany; S Luttgen; Dept. of Phys., Philipps-Univ., Marburg, Germany; W Stolz; Dept. of Phys., Philipps-Univ., Marburg, Germany
Журнал:
Semiconductor Science and Technology
Дата:
1994-11-01
Аннотация:
The coherent dynamics of exciton wavepackets in (GaIn)As/GaAs as well as (GaIn)As/Ga(PAs) multiple quantum well structures is studied by means of transient four-wave mixing (FWM) experiments. The wavepackets are generated by simultaneous excitation of several exciton transitions with laser pulses of about 100 fs duration. The time-integrated FWM signals exhibit a pronounced modulation superimposed on the overall decay which can be attributed to the quantum interference of the different eigenstates. In the time-resolved FWM signals this interference is not present, reflecting the interplay between many-body Coulomb effects and inhomogeneous broadening. This experimental technique is then employed to extract the exciton binding energies in pseudomorphic symmetrically strained (GaIn)As/GaIPAs) with various In contents.
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