SIZE, SHAPE, AND COMPOSITION OF LUMINESCENT SPECIES IN OXIDIZED SI NANOCRYSTALS AND H-PASSIVATED POROUS SI

Citation
S. Schuppler et al., SIZE, SHAPE, AND COMPOSITION OF LUMINESCENT SPECIES IN OXIDIZED SI NANOCRYSTALS AND H-PASSIVATED POROUS SI, Physical review. B, Condensed matter, 52(7), 1995, pp. 4910-4925
Citations number
96
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
01631829
Volume
52
Issue
7
Year of publication
1995
Pages
4910 - 4925
Database
ISI
SICI code
0163-1829(1995)52:7<4910:SSACOL>2.0.ZU;2-C
Abstract
Near-edge and extended x-ray-absorption fine-structure measurements fr om a wide variety of oxidized Si nanocrystals and H-passivated porous Si samples, combined with electron microscopy, ir absorption, forward recoil scattering, and luminescence emission data, provide a consisten t structural picture of the species responsible for the luminescence o bserved in these systems. For porous Si samples whose luminescence wav elengths peak in the visible region, i.e., at <700 nn, their mass-weig hted-average structures are determined here to be particles (not wires ) whose short-range character is crystalline and whose dimensions-typi cally <15 Angstrom-are significantly smaller than previously reported or proposed. Results are also presented which demonstrate that the obs erved visible luminescence is not related to either a photo-oxidized S i species in porous Si or an interfacial suboxide species in the Si na nocrystals. The structural and compositional findings reported here de pend only on sample luminescence behavior, not on how the luminescent particles are produced, and thus have general implications in assignin g quantum confinement as the mechanism responsible for the visible lum inescence observed in both nanocrystalline and porous silicon.