Actions for X-ray absorption spectroscopy from H-passivated porous Si and oxidized Si nanocrystals [electronic resource].

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X-ray absorption spectroscopy from H-passivated porous Si and oxidized Si nanocrystals [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 1994.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
11 pages : digital, PDF file
Additional Creators
Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
Quantum confinement in nanoscale Si structures is widely believed to be responsible for the visible luminescence observed from anodically etched porous silicon (por-Si), but little is known about the actual size or shape of these structures. Extended x-ray absorption fine structure data from a wide variety of por-Si samples show significantly reduced average Si coordination numbers due to the sizable contribution of surface-coordinated H. (The IUSI ratios, as large as 1.2, were independently confirmed by ir-absorption and α-recoil measurements.) The Si coordinations imply very large surface/volume ratios, enabling the average Si structures to be identified as crystalline particles (not wires) whose dimensions are typically <15 Å. Comparison of the size-dependent peak luminescence energies with those of oxidized Si nanocrystals, whose shapes are known, shows remarkable agreement. Furthermore, near-edge x-ray absorption fine structure measurements of the nanocrystals shows the outer oxide and interfacial suboxide layers to be constant over a wide range of nanocrystal sizes. The combination of these results effectively rules out surface species as being responsible for the observed visible luminescence in por-Si, and strongly supports quantum confinement as the dominant mechanism occurring in Si particles which are substantially smaller than previously reported or proposed.
Report Numbers
E 1.99:lbl--36911
E 1.99: conf-941144--149
conf-941144--149
lbl--36911
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Other Subject(s)
Note
Published through SciTech Connect.
11/01/1994.
"lbl--36911"
" conf-941144--149"
"DE95012352"
Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 28 Nov - 9 Dec 1994.
Friedman, S.L.; Marcus, M.A.; Schuppler, S.
Funding Information
AC03-76SF00098
View MARC record | catkey: 14449649