Absence of band-gap surface states on clean amorphous silicon
- 1 February 1981
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine Part B
- Vol. 43 (2), 273-282
- https://doi.org/10.1080/13642818108221898
Abstract
Photoemission studies have been made of the clean and oxidized amorphous Si surface at hv = 10·2, 21·2 and 40·8 eV. For the clean surface, no emission from surface states in the band gap is found and exposure to small amounts of oxygen results in no preferential decreases in emission near the valence band edge. We place an upper limit of 4 × 1013 surface states/cm2 in the gap and conclude that any residual states in the gap are not intrinsic to the amorphous Si vacuum interface. A small amount of oxygen induces a broad valence band peak 2 to 5 eV below the valence band maximum; this we associated with a SiOx structure. Furthermore, we find that exposure to 108 L oxygen produces valence band structure similar but not identical to SiO2 and a depletion of the SiOx emission.Keywords
This publication has 14 references indexed in Scilit:
- Photoemission studies of the surface states and oxidation of group IV semiconductorsJournal of Vacuum Science and Technology, 1977
- Photoemission and electron energy loss spectroscopy of GeO2 and SiO2Applied Physics Letters, 1974
- Electron orbital energies of oxygen adsorbed on silicon surfaces and of silicon dioxidePhysical Review B, 1974
- Electronic transitions of oxygen adsorbed on clean silicon (111) and (100) surfacesPhysical Review B, 1974
- X-Ray Photoemission Spectra of Crystalline and Amorphous Si and Ge Valence BandsPhysical Review Letters, 1972
- Electronic Structure of Amorphous Si from Photoemission and Optical StudiesPhysical Review B, 1972
- Photoemission Measurements of the Valence Levels of Amorphous SiPhysical Review Letters, 1971
- Lack of Photoemission Evidence for Tailing of Density of States into Energy Gap of Amorphous SiPhysical Review Letters, 1971
- A high density form of amorphous GePhysics Letters A, 1970
- Structural, Optical, and Electrical Properties of Amorphous Silicon FilmsPhysical Review B, 1970