Exchange disorder band bending of the Cd_1−xFe_xS diluted magnetic semiconductor

Abstract

The energy of excitons A, B, and C of Cd, -,Fe,S (x < 0.02) is studied as a function of Fe concentration at T = 10 K in the absence of a magnetic field. The observed band bending effect (largest for exciton A) is attributed to the s, p-d exchange interaction correction resulting from the exchange disorder.A particular class of mixed crystals is formed by the so-called diluted magnetic semiconductors (DMS, see e.g.[7]), in which nonmagnetic cations A are substituted by magnetic ions (typically transition metal ions, such as Mn, Fe, or Co). For these materials the s, p-d exchange interaction between band electrons and magnetic ions strongly modifies the random chemical potential and consequently the bowing effects. The bowing of the energy gap was observed for CdMnS [S], ZnMnSe [9, lo], and ZnMnTe [ll]. However, ') Chung Li 32023,