PHOTOEMISSION-STUDY OF AG ON HYDROGENATED AMORPHOUS-SILICON

We report a photoemission study of Ag overlayers deposited on a hydrog enated amorphous silicon (a-Si:H) film at room temperature, using sync hrotron radiation as a probe. Unlike the two other interfaces, Au/a-Si :H and Cr/a-Si:H, where the metal deposits start to intermix with the a-Si substrate after a critical thickness is exceeded, the Ag/a-Si:H i nterface is abrupt without any indication of intermixing. The non-inte rmixing nature is reminiscent of its crystalline counterpart. More int erestingly, we have found a unique behavior of small metal adatoms on a-Si:H; that is, they reside favorably on the dangling-bond sites. Str ong hydrogen passivation on the surface prevents the gathered adatoms from coalescing.