MAGNETOEXCITONS AND LANDAU-LEVELS IN STRAINED ZNTE AND ZNSE LAYERS

Interband absorption in ultra-thin strained MBE-grown epilayers of ZnT e and ZnSe has been measured in magnetic fields up to 6 T. The spectra simultaneously uncover two effects of the magnetic field: diamagnetic shifts of exciton states, and the rich oscillatory structure arising from formation of Landau levels in the continuum. The observed spectra l features are analyzed using the 8 x 8 k.p model, which takes into ac count the residual strain introduced during sample preparation. From t his analysis we extract values for both the energy gaps and the excito n binding energies with high accuracy. Effects of electron-hole correl ation and resonant magneto-polaron coupling in the continuum absorptio n are also discussed. (C) 1998 Elsevier Science B.V. All rights reserv ed.