Terahertz Induced Non-linear Electron Dynamics in Nanoantenna Coated Semiconductors at the Sub-picosecond Timescale Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/hx11xj270

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • This dissertation is an exploration of the material response to Terahertz (THz) radiation. Specifically we will explore the ultrafast electron dynamics in the nonperturbative regime in semiconductors that have been patterned with nanoantenna arrays using broadband, high intensity, THz radiation. Three main semiconductor materials will be studied in this work. The first is VO₂ which undergoes a phase transition from an insulator, when it is below 67° C, to a metal, when it is above 67° C. The second and third materials are Si and GaAs which are two of the most commonly used semiconductors. We study the insulator to metal transition (IMT) of VO₂ and its response to high field THz radiation. The near room temperature IMT for VO₂ makes it a very promising material for electrical and photonic applications. We demonstrate that with high field THz the IMT transition can be triggered. This transition is induced on a sub-cycle timescale. We also demonstrate a THz field dependent reduction in the transition temperature for the IMT when transitioning from both below T[subscript c] to above as well as from above T[subscript c] to below. This transition is not equal for the above and below cases and leads to a narrowing of the hysteresis curve of the IMT. The thin film Fresnel coefficients, along with a phenomenological model developed for the nanoantenna patterned VO₂, are also used to calculate the sheet conductivity of the VO₂ sample. We show, using this sheet conductivity and its relation to the band gap, that the bang gap in the insulating phase has a strong dependence on the incident THz radiation with larger fields reducing the band gap from 1.2 eV at low incident THz fields to 0.32 eV at high incident THz fields. The ultrafast, non-equilibrium, electron dynamics of GaAs and Si were also explored. GaAs and Si are the two most prevalent semiconductors in use today and with the decrease in size and increase in clock speeds of transistors a deep understanding of the ultrafast high field electron dynamics of these materials is of vital importance. Using THz time domain spectroscopy we investigate the transition rates of electrons excited by a 800 nm optical pump. We show that the optically induced transition for GaAs happens on a shorter timescale than that of Si. We also investigate the THz transmission dependence on the indecent THz field. We show that intense THz fields enhance the transmission through the sample. The increase in transmission is due to intervalley scattering which increases the effective mass of the electrons resulting in a decrease in the conductivity the sample.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Keyword
Subject
Rights Statement
Peer Reviewed
Language
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2016-08-19T17:40:12Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) StickelAndrewD2016.pdf: 9230976 bytes, checksum: 16e1ea71f492848048c4f40e8fd9f380 (MD5) Previous issue date: 2016-08-10
  • description.provenance : Submitted by Andrew Stickel (stickean@oregonstate.edu) on 2016-08-17T21:52:44Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) StickelAndrewD2016.pdf: 9230976 bytes, checksum: 16e1ea71f492848048c4f40e8fd9f380 (MD5)
  • description.provenance : Approved for entry into archive by Julie Kurtz(julie.kurtz@oregonstate.edu) on 2016-08-18T16:37:31Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) StickelAndrewD2016.pdf: 9230976 bytes, checksum: 16e1ea71f492848048c4f40e8fd9f380 (MD5)
  • description.provenance : Submitted by Andrew Stickel (stickean@oregonstate.edu) on 2016-08-16T21:45:57Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) StickelAndrewD2016.pdf: 9230987 bytes, checksum: 7c5aa4c1db702a3cd7105f0a47bd9b02 (MD5)
  • description.provenance : Rejected by Julie Kurtz(julie.kurtz@oregonstate.edu), reason: Hi Andrew, Everything looks good except the commencement date on the bottom of the title page needs to be changed to - Commencement June 2017. Also for your defense date which appears on the Abstract, Copyright, Title and Approval pages, change Aug to August. Once revised, log back into ScholarsArchive and go to the upload page. Replace the attached file with the revised PDF and resubmit. Thanks, Julie on 2016-08-17T18:58:33Z (GMT)
  • description.provenance : Approved for entry into archive by Laura Wilson(laura.wilson@oregonstate.edu) on 2016-08-19T17:40:12Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: bb87e2fb4674c76d0d2e9ed07fbb9c86 (MD5) StickelAndrewD2016.pdf: 9230976 bytes, checksum: 16e1ea71f492848048c4f40e8fd9f380 (MD5)

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items