ISSN:
1063-7826
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
Notes:
Abstract The optical and magnetooptical properties of strained InGaAs/GaAs quantum-well heterostructures grown by molecular-beam epitaxy were studied at T=1.7 K in magnetic fields B⩽7.5 T. The well-resolved oscillatory structure of the magnetoabsorption spectra makes it possible to reproduce the “fan diagrams” for transitions between Landau levels of the HH1E1 quantum-confined states, taking into account exciton binding energies calculated variationally. Based on these results, reduced cyclotron masses of carriers were calculated for quantum wells with various indium contents. A self-consistent variational solution to the exciton problem in the structure under study shows that for weak type-II potentials the effect of Coulomb localization of the hole leads to a relative increase in the oscillator strength of the LH1E1 exciton transition. In this case the LH1E1 and LH3E1 exciton transitions remain spatially direct and retain a considerable intensity. The calculated splitting of ∼9 meV between these two states in zero magnetic field is found to be in agreement with experiment. The significant oscillator strength of light-hole excitons, along with the observed doublet structure, are experimental confirmations that electron-hole attraction can transform a rather low barrier for light holes in a type-II structure into a quantum well with a parabolic “Coulomb” shape near its bottom, i.e., a “Coulomb well.”
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1134/1.1187141
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