Date of Graduation

Fall 2025

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, & Materials Science

Committee Chair

Kartik Ghosh

Abstract

This study aims to investigate the optical properties of Dy-doped MoO₃ thin films. MoO₃ is a transition metal oxide that is wide band gap semiconductor. As a transition-metal oxide, it has been widely studied for its tunable properties. However, there is little literature on the subject of Dysprosium doped MoO₃, and none found as of now on thin film Dy-MoO₃ . This indicates that this topic is at best under reported, and thin film Dy-MoO₃ possesses a certain novelty. Unlike most transition metal oxides, undoped MoO₃ has a negligible crystal field splitting. This is due to the electron vacancy of the outer 4d-orbital. The addition of Dy+3 ion introduces partially filled 4f-orbitals. The host MoO₃ then applies a crystal field on the Dy3+ ion and lifts the degeneracy. This splits the energy levels, and the result is enhanced optical properties including appreciable photoluminescent emission. The Dy-doped MoO₃ films were grown using a pulsed laser deposition technique and were doped with 1% and 5% concentrations of dysprosium oxide. This study found that 1%Dy-MoO₃ has potential for intriguing optical properties, but reproducibility is difficult. Thin films that were grown with 5%-concentration Dysprosium oxide were found to grow with Dy3+ ion inside the MoO₃ host. Reflectance UV-VIS and temperature-dependent Time Resolved Photoluminescence were utilized in finding approximate band gap and activation energy. The band gap was found to be 3.21 eV. The activation energy, the minimum energy before non-radiative recombination begins, is 12.5 meV. There is much work that needs to be done on this topic. Thin film Dy-doped MoO₃ has promising results that should be further explored.

Keywords

thin film, fluorescence, time-resolved photoluminescence, crystal field splitting, transition-metal oxides

Subject Categories

Optics | Physics

Copyright

© Jessica Fink

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