Journal Article

FZJ-2020-01559

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Porous Si Partially Filled with Water Molecules—Crystal Structure, Energy Bands and Optical Properties from First Principles

Shchur, Y. (Corresponding author) ; Pavlyuk, O. ; Andrushchak, A. S. ; Vitusevich, S.FZJ* ; Kityk, A. V.

2020
MDPI Basel

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Please use a persistent id in citations: http://hdl.handle.net/2128/24679  doi:10.3390/nano10020396

Abstract: The paper reports the results on first-principles investigation of energy band spectrum andoptical properties of bulk and nanoporous silicon. We present the evolution of energy band-gap,refractive indices and extinction coefficients going from the bulk Si of cubic symmetry to porous Siwith periodically ordered square-shaped pores of 7.34, 11.26 and 15.40 Å width. We consider twonatural processes observed in practice, the hydroxylation of Si pores (introduction of OH groups intopores) and the penetration of water molecules into Si pores, as well as their impact on the electronicspectrum and optical properties of Si superstructures. The penetration of OH groups into the pores ofthe smallest 7.34 Å width causes a disintegration of hydroxyl groups and forms non-bonded protonswhich might be a reason for proton conductivity of porous Si. The porosity of silicon increasesthe extinction coefficient, k, in the visible range of the spectrum. The water structuring in pores ofvarious diameters is analysed in detail. By using the bond valence sum approach we demonstratethat the types and geometry of most of hydrogen bonds created within the pores manifest a structuralevolution from distorted hydrogen bonds inherent to small pores (7 Å) to typical hydrogen bondsobserved by us in larger pores (about15 Å) which are consistent with those observed in a wide databaseof inorganic crystals.

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Contributing Institute(s):

1. Bioelektronik (IBI-3)

Research Program(s):

1. 523 - Controlling Configuration-Based Phenomena (POF3-523) (POF3-523)

Appears in the scientific report 2020

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Database coverage:
; ; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Ebsco Academic Search ; IF < 5 ; JCR ; PubMed Central ; Science Citation Index Expanded ; Web of Science Core Collection

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