The nature of photoexcitations and carrier multiplication in low-dimensional semiconductors

Aditya Kulkarni

Research output: ThesisDissertation (TU Delft)

82 Downloads (Pure)

Abstract

The aim of this thesis is to study the nature of photoexcitations and carrier multiplication in low-dimensional semiconductors using ultrafast spectroscopy techniques. Ongoing from a macroscopic scale to a nanoscale, the electronic and
optical properties of a material become size dependent, and differ significantly from their bulk counterpart due to quantum confinement, and the surrounding dielectric environment. Electrons and holes in nano-semiconductors can attract each other to form neutral bound electron-hole pairs known as excitons. Stable robust excitons are useful to achieve optical gain and lasing. The Coulomb interaction between electrons and holes in nano-semiconductors is enhanced due to quantum confinement, which can lead to the creation of multiple electron-hole pairs per single absorbed photon via a process called carrier multiplication (CM). CM is beneficial to achieve a power conversion efficiency in a solar cell beyond the Shockley-Quiesser limit.
Original languageEnglish
Awarding Institution
  • Delft University of Technology
Supervisors/Advisors
  • Siebbeles, L.D.A., Supervisor
Award date24 Jun 2019
Print ISBNs978-94-028-1559-7
DOIs
Publication statusPublished - 2019

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