BARE AND POLARON BAND PARAMETERS OF ZNSE AND THE ENERGY-SPECTRUM OF QWS IN THE (ZN,CD)SE (ZN,MG)SSE HETEROSYSTEM/

Magneto-optical measurement of superthin (less than or equal to 1 mu m ) ZnSe samples have been carried out in magnetic fields up to 7.5 T at T = 1.7 K. Treatment of the obtained spectra gives two sets of band p arameters of bulk ZnSe, ''bare'' and ''polaron'' ones. Optical propert ies of MQWs in (Zn,Cd)Se/(Zn,Mg)SSe heterostructures MBE grown on GaAs substrates have been studied. Absorption spectra of free samples etch ed from GaAs substrate have been obtained. The calculation of the carr ier spectrum and exciton binding energies in strained QWs have been ca rried out in the framework of the eight-band Kane model. It is demonst rated that the best agreement between calculated and measured energy p ositions of the absorption maxima of ZnCdSe/ZnSSe MQWs can be obtained only using two sets of band parameters: ''bare'' one for the QW level s and ''polaron'' one for the exciton binding energies. (C) 1998 Elsev ier Science B.V. All rights reserved.