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Strained Interface Defects in Silicon Nanocrystals
Author(s) -
Lee Benjamin G.,
Hiller Daniel,
Luo JunWei,
Semonin Octavi E.,
Beard Matthew C.,
Zacharias Margit,
Stradins Paul
Publication year - 2012
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201200572
Subject(s) - dangling bond , materials science , photoluminescence , passivation , nanocrystal , optoelectronics , silicon , pseudopotential , quantum efficiency , absorption (acoustics) , band gap , oxide , nanotechnology , chemical physics , condensed matter physics , composite material , physics , layer (electronics) , metallurgy
The surface of silicon nanocrystals embedded in an oxide matrix can contain numerous interface defects. These defects strongly affect the nanocrystals’ photoluminescence efficiency and optical absorption. Dangling‐bond defects are nearly eliminated by H 2 passivation, thus decreasing absorption below the quantum‐confined bandgap and enhancing PL efficiency by an order of magnitude. However, there remain numerous other defects seen in absorption by photothermal deflection spectroscopy; these defects cause non‐radiative recombination that limits the PL efficiency to <15%. Using atomistic pseudopotential simulations, we attribute these defects to two specific types of distorted bonds: Si‐Si and bridging Si‐O‐Si bonds between two Si atoms at the nanocrystal surface.