Coexistence of excitons and Landau states in In _{0.53}Ga _{0.47}As/InP quantum wells at room temperature
Abstract
We have studied the magnetooptical Kerr ellipticity of the electronheavyhole states of two latticematched InGaAs/InP multiquantumwells (MQW) with different barrier widths at room temperature. Using Lorentzian line shapes the analysis of the oscillations in the spectra reveals excitonic states and up to six Landau states. The energy shifts of the excitonic ground state in low and high magnetic fields allow us to estimate the dimensionality of the electronic system. For the higher excited states no excitonic behaviour is observable. At higher magnetic fields clear deviations from the linear Landaushift occur. Using the nonparabolicity of the conduction band, described by the k· ptheory by Kane, and a constant heavyhole mass m_{hh} we are able to assign every energy transition to its corresponding Landau level. From the Landau charts we evaluate the energy dependence of the reduced effective mass up to 200 meV above the band gap of InGaAs. The heavyhole effective mass shows no dependence on energy, but its value is influenced by the strength of the quantum confinement.
 Publication:

Physica B Condensed Matter
 Pub Date:
 May 1998
 DOI:
 10.1016/S09214526(97)009113
 Bibcode:
 1998PhyB..246..262J
 Keywords:

 MAGNETOOPTICAL KERR ELLIPTICITY;
 EXCITONS;
 QUANTUM WELLS;
 NONPARABOLICITY