Award Date

12-15-2025

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Committee Member

Joshua Island

Second Committee Member

David Shelton

Third Committee Member

Rebecca Martin

Fourth Committee Member

Clemens Heske

Number of Pages

175

Abstract

On-chip terahertz time-domain spectroscopy (THz-TDS) is a technique useful for measuring the ultrafast electrodynamics of two-dimensional (2D) electronic systems. Charge carrier collisions occur on the sub-picosecond time scale, and strongly correlated electron interactions (such as superconductivity) typically have energies on the order of milli-electron-volts. These phenomena fall within the terahertz bandwidth, which has historically been difficult to access. Commercial electronics operate with transistors capable of switching rates of around 100 GHz, while small band gap semiconductors (like InGaAs) can detect light down to 0.75 eV (180 THz). When combined with the difficulty of measuring 2D layered materials, with lateral sizes smaller than the wavelength of terahertz light, it becomes clear that a highly specialized technique is required. We discuss the mechanisms by which THz-TDS is performed and our development of the technique. There are three projects we highlight: the usage of an optically-transparent material as a local electrostatic gate, the integration of such a material into a THz-TDS spectrometer to measure ultrafast electronic behavior in graphene, and the pumping of transition-metal dichalcogenides with circularly polarized light to see unique valley-selective behavior. We will discuss the results of these projects and prospects for future research in terahertz spectroscopy.

Keywords

optoelectronic; transition-metal dichalcogenide; valley Hall effect

Disciplines

Condensed Matter Physics | Physical Sciences and Mathematics | Physics

File Format

PDF

File Size

6300 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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