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.

Space charge layer, metallization and collective excitations of the Bi/GaAs interface / DE RENZI, Valentina; BIAGI, Roberto; BETTI, Maria Grazia; MARIANI, Carlo. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - STAMPA. - 49:(1994), pp. 8198-8205.

Space charge layer, metallization and collective excitations of the Bi/GaAs interface.

DE RENZI, Valentina;BIAGI, Roberto;BETTI, Maria Grazia;MARIANI, Carlo
1994

Abstract

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.
49
8198
8205
Space charge layer, metallization and collective excitations of the Bi/GaAs interface / DE RENZI, Valentina; BIAGI, Roberto; BETTI, Maria Grazia; MARIANI, Carlo. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - STAMPA. - 49:(1994), pp. 8198-8205.
DE RENZI, Valentina; Biagi, Roberto; Betti, Maria Grazia; Mariani, Carlo
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/10728
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