Nuclear magnetic resonance studies of amorphous silicon hydrides: proton spin dynamics

dc.contributor.author Fry, Charles
dc.contributor.department Chemistry
dc.date 2018-08-17T06:34:16.000
dc.date.accessioned 2020-07-02T06:03:08Z
dc.date.available 2020-07-02T06:03:08Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 1985
dc.date.issued 1985
dc.description.abstract <p>The island size in amorphous silicon hydride has been estimated to be (TURN)75 (+OR-) 30(ANGSTROM) for an assumed three-dimensional domain, or 40 (+OR-) 20(ANGSTROM) for a two-dimensional domain. These results were obtained using spin-diffusion via the Goldman-Shen experiment;Arguments have been given to suggest that the interpretation of the Lorentzian line shape should be reexamined. Several reasons, and some calculations provide motive for interpreting the Lorentzian line shape as due to monohydrides bonded to the interstitial surfaces parallel to the growth direction, where the surface has reconstructed to give the larger than expected internuclear separations leading to the narrow Lorentzian line shape;A combination of spin-lattice relaxation measurements and the Carr-Purcell-Meiboom-Gill (CPMG) experiment led to the identifica- tion of two hydrogen environments in addition to the monohydride Lorentzian line shape and the clustered Gaussian line shape. The fact that the Lorentzian line shape is due to a random distribution gives part of the distribution of monohydrides having nearest-neighbor separations so large that these monohydrides echo during a Hahn echo sequence. The information obtained from these experiments led to the conclusion that poor films have a small deviation in internuclear spacings, whereas good films have a much larger deviation in internuclear spacings. This result should be a good measure of the growth conditions during deposition;Molecular hydrogen is identified and quantified using the CPMG experiment. The decay rate of the m-H(,2) during the CPMG experiment gives a direct measure of the strongest residual proton-proton dipolar;interaction, which then gives a lower limit of 10(ANGSTROM) for void dimensions. This result is a clear measure of the void size; ('1)DOE Report IS-T-1116. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/7846/
dc.identifier.articleid 8845
dc.identifier.contextkey 6323887
dc.identifier.doi https://doi.org/10.31274/rtd-180813-5045
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/7846
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/80768
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/7846/r_8514398.pdf|||Sat Jan 15 01:54:53 UTC 2022
dc.subject.disciplines Organic Chemistry
dc.subject.keywords Chemistry
dc.subject.keywords Physical chemistry
dc.title Nuclear magnetic resonance studies of amorphous silicon hydrides: proton spin dynamics
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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