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Title: On the role of spatial position of bridged oxygen atoms as surface passivants on the ground-state gap and photo-absorption spectrum of silicon nano-crystals

Silicon nano-crystals (NCs) are potential candidates for enhancing and tuning optical properties of silicon for optoelectronic and photo-voltaic applications. Due to the high surface-to-volume ratio, however, optical properties of NC result from the interplay of quantum confinement and surface effects. In this work, we show that both the spatial position of surface terminants and their relative positions have strong effects on NC properties as well. This is accomplished by investigating the ground-state HOMO-LUMO band-gap, the photo-absorption spectra, and the localization and overlap of HOMO and LUMO orbital densities for prototype ∼1.2 nm Si{sub 32–x}H{sub 42–2x}O{sub x} hydrogenated silicon NC with bridged oxygen atoms as surface terminations. It is demonstrated that the surface passivation geometry significantly alters the localization center and thus the overlap of frontier molecular orbitals, which correspondingly modifies the electronic and optical properties of NC.
Authors:
;  [1] ;  [1] ;  [2] ;  [3]
  1. School of Electrical and Computer Engineering, University of Tehran, Tehran 14395-515 (Iran, Islamic Republic of)
  2. (Austria)
  3. Institute for Microelectronics, Technische Universität Wien, Gusshausstrasse 27-29/E360, Wien A-1040 (Austria)
Publication Date:
OSTI Identifier:
22492980
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION SPECTRA; CONFINEMENT; CRYSTALS; GROUND STATES; HYDROGENATION; NANOSTRUCTURES; OPTICAL PROPERTIES; OPTOELECTRONIC DEVICES; OXYGEN; PASSIVATION; SILICON; SURFACES; TUNING