Magneto-optical and cyclotron resonance study of semiconductor nanostructures in very high magnetic fields

We have studied new features of semiconductor nano-structures in cyclotron resonance and magneto-optical spectroscopy under very high magnetic fields up to a few megagauss. The new features are attributed to the shrinkage of wave-functions of electrons, holes and excitons. In PbSe/PbEuTe quantum dots that are regularly arranged to form an fcc-like lattice, sharp cyclotron resonance peaks from PbSe quantum dots were observed. It was found that the peaks show a number of anomalous features such as splitting, a remarkable dependence of the intensity on the wavelength, or a peculiar angular dependence of the resonance field. In the photoluminescence spectra of excitons for CdSe/ZnSe quantum dots, GaP/AlP and GaAs/AlAs short period superlattices, a remarkable decrease of the peak intensity and a red shift of the exciton peak were observed with increasing magnetic field; these effects are attributed to the general nature of excitons consisting of spatially separated electrons and holes.