CHEMICAL-REACTIVITY AND BAND OFFSET AT THE CDS SI INTERFACE/

Transport phenomena at heterojunctions are critically governed by chem ical reactivity and the valence-band offset at the interface. Here we report our investigations carried out on the CdS/Si(111) interface usi ng X-ray and ultraviolet photoelectron spectroscopy and glancing-incid ence X-ray diffraction. Weak reactivity between CdS and Si(111) has be en observed. A partial charge transfer interaction is suggested to exp lain the weak reactivity at the interface on the basis of the electron egativity difference. Hexagonal phase of CdS is preferentially grown a t 700 K. The valence-band offsets obtained for the interfaces grown at 300 and 700 K are 1.6 and 1.3 eV, respectively. The effects of chemic al reactivity and disorder are discussed.