Hot carrier transfer and thermal transport in suspended nm-thick WS2

dc.contributor.advisor Xinwei . Wang
dc.contributor.author Zobeiri, Hamidreza
dc.contributor.department Mechanical Engineering
dc.date 2020-02-12T23:02:16.000
dc.date.accessioned 2020-06-30T03:21:08Z
dc.date.available 2020-06-30T03:21:08Z
dc.date.copyright Sun Dec 01 00:00:00 UTC 2019
dc.date.embargo 2001-01-01
dc.date.issued 2019-01-01
dc.description.abstract <p>This work reports the first results on the conjugated hot carrier diffusivity (D) and thermal conductivity (κ) of suspended nm-thick WS2 structures. A novel nET-Raman technique is developed to distinguish and characterize these two properties by constructing steady and transient states of different laser heating and Raman probing sizes. The nET-Raman uses a nanosecond pulsed laser and a continuous wave laser for exciting Raman signals and heating samples. κ is found to increase from to W·m−1·K−1 when the sample’s thickness increases from 13 to 107 nm. This increase is attributed to the decreased effect of surface phonon scattering in thicker samples. Also, hot carrier diffusion length (ΔrHC) for these samples are measured without knowledge of hot carrier’s lifetime (τ). Measured D of these four samples are in close range (except the thickest sample). This is due to the fact that lattice scattering for all these samples is similar and there is no substrate effect on our suspended films. nET-Raman is very robust and has negligible effect from laser absorption depth, sample thickness, and laser spot drift during measurement.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/etd/17820/
dc.identifier.articleid 8827
dc.identifier.contextkey 16525334
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/17820
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/32003
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/etd/17820/Zobeiri_iastate_0097M_18425.pdf|||Fri Jan 14 21:29:29 UTC 2022
dc.subject.disciplines Mechanical Engineering
dc.subject.keywords Raman spectroscopy
dc.subject.keywords Semiconductors
dc.subject.keywords Thermal conductivity
dc.subject.keywords Thermal transport
dc.title Hot carrier transfer and thermal transport in suspended nm-thick WS2
dc.type thesis
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication 6d38ab0f-8cc2-4ad3-90b1-67a60c5a6f59
thesis.degree.discipline Mechanical Engineering
thesis.degree.level thesis
thesis.degree.name Master of Science
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