The collective excitations and the metallization of the Bi/GaAs(I 10) interface grown at room temperature, up to the completion of a few tens of a monolayer, have been studied by means of the high-resolution electron-energy-loss spectroscopy (HREELS). Through analysis of the HREELS data, also by means of an appropriate semiclassical dielectric model, the modifications experienced by the substrate-related loss structures (Fuchs-Kliewer phonon and dopant-induced free-carrier plasmon) and by the quasielastic peak are related to changes in the dielectric response of the overlayer and in the semiconductor space-charge region. The influence of bismuth is effective in enlarging the depletion layer thickness, leaving the interface semiconducting at the monolayer-coverage scale. A band bending value of 0.56 eV is obtained at the coverage of one monolayer on the highly n-type doped sample (n approximately 2.7 X 10(18) cm-3); a determination free from any possible surface photovoltaic effect. At coverages greater than two monolayers, which corresponds to a structural transition, the intermediate structural phase becomes metallic, thus marking a clear semiconductor-metal transition. This intermediate metallic stage further develops towards the formation of actual semimetallic crystalline bismuth layers oriented with the basal plane parallel to the substrate surface.
|Anno di pubblicazione:||1994|
|Titolo:||Space charge layer, metallization and collective excitations of the Bi/GaAs interface.|
|Autore/i:||DE RENZI V; BIAGI R; BETTI MG; MARIANI C|
|Codice identificativo ISI:||WOS:A1994NG11600041|
|Codice identificativo Scopus:||2-s2.0-25944463319|
|Tipologia||Articolo su rivista|
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