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Excitons in Transition Metal Dichalcogenide van Waals heterostructures

  • Author(s): Calman, Erica
  • Advisor(s): Butov, Leonid V
  • et al.
Abstract

Excitons are quasi-partciles consisting of an electro-statically bound electron and hole which have long been observed in semiconducting and insulating materials. A spatially indirect exciton (IX) is an exciton in which the electron and the hole are spatially separated. This is achieved through the use of a static electric field and engineered semiconductor heterosteructures. Indirect excitons interact with one another and can effeciently re-radiate, so they provide a means for light to interact with light in solid media, and can thus be used for ecient optical signal processing. However, the most common material for studying indirect excitons (GaAs) cannot support excitons at temperatures above ~ 100 K. This limitation, due to hermal fluctuations having enough energy to cause exciton dissocation prevents the creation of practical devices for excitonic signal processing. This dissertation demonstrates an increase in the binding energy and thus operating temperature of indirect excitons by utelizing van der Waals transition metal dichalcogenide heterostructures. These atomically thin materials have binding energies on the order of 0:5 eV which support excitons at 300 K.

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