CONTACTLESS ELECTROREFLECTANCE STUDY OF STRAINED ZN0.79CD0.21SE ZNSE DOUBLE-QUANTUM WELLS/

We have studied various excitonic transitions of strained Sn0.79Cd0.21 Se/ZnSe double quantum wells, grown by molecular beam epitaxy on (100) GaAs substrates, using contactless electroreflectance (CER) at 15 and 300 K. A number of intersub-band transitions in the CER spectra from the sample have been observed. An analysis of the CER spectra has led to the identification of various excitonic transitions, mnH(L), betwee n the mth conduction band state and the nth heavy (light)-hole band st ate. The conduction-band offset Q(c), is used as an adjustable paramet er to study the band offset in the strained Zn0.79Cd0.21Se/ZnSe system . The value of Q(c), is determined to be 0.67+/-0.03. (C) 1998 America n Institute of Physics. [S0021-8979(98)08601-0].