ELECTRONIC STATES AND BAND LINEUPS IN C-SI(100) A-SI1-XCX-H HETEROJUNCTIONS/

Heterostructures formed by depositing in situ amorphous hydrogenated s ilicon-carbon alloys on Si(100) substrates were characterized by photo electric-yield spectroscopy, UPS, and XPS. It is shown that both subst rate and overlayer valence-band tops can be identified on the photoele ctric-yield spectrum, thus allowing a direct and precise determination of the band lineup. We find a valence-band discontinuity varying from 0.44 eV to 1.00 eV for carbon content ranging from 0 to 50%. The pres ent data can be used as a test for the lineup theories and strongly su pport the interface dipole models.