Electronic properties of ionic insulators on metal and semiconductor surfaces: RbCl on Si(100) and W(110)

The nature of bonding of RbCl on the Si(100) and W(110) surfaces has been investigated on the basis of neutralization and inelastic scattering of low‐energy D⁺ ions. It is found that RbCl is dissociatively adsorbed on both substrates in a low coverage regime (<0.4 ML). The resultant Rb and Cl adatoms are covalently bonded to the W(110) surface while, on the Si(100) surface, Cl reacts preferentially with the dangling bond and Rb is ionically adsorbed on the surface. The hydrogenation of the Si(100) surface prevents dissociative adsorption and enables the growth of an ionic RbCl film from the low‐coverage limit.