Nanoimprint Lithography Patterning for Perovskite Based Lasers

Research output: ThesisMaster's Thesis

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Abstract

In this thesis, nanoimprint lithography (NIL) is evaluated as a possible process route to develop 2nd order one-dimensional distributed feedback Bragg (DFB) resonators for perovskite based thin film lasers. The main focus hereby lies on the perovskite methylammonium lead iodide (CH3NH3PbI3, MAPbI3). Grating resonators are prepared using an all-solution process and are evaluated using optical multispectral analysis, electron microscopy, as well as simulations. Optically pumped lasing with low threshold (~80µJ/cm²) and narrow linewidth (<0.1nm) from a MAPbI3 layer coupled to a grating which is processed via UV-NIL is demonstrated. Identification of lasing versus other phenomena like amplified spontaneous emission (ASE) or random lasing (RL) in this scenario is aided by studying angular emission features, translational invariance, and far-field images. During experiments, it is found that an optical excitation with a linear shape can prevent parasitic losses through ASE. Grating-free areas should not be excited to restrict the influence of RL. It is noted that coupled wave theory is necessary for conclusive proof of lasing, which would exceed the scope of this thesis. The evaluation of different processing parameters like curing times and temperatures highlights that curing temperatures need to be low enough not to degrade the perovskite, but high enough to enable proper adhesion. The dry-etch process for the preparation of master stamps used during NIL is revised. For this purpose, etch parameters are varied and the resulting grating structures are analyzed using cross-sectional scanning electron microscopy (XSEM). The thesis demonstrates that the UV-NIL route can produce gratings that support lasing. The experienced adhesion problems point to opportunities for further improvement and research in the scope of similar thin film systems. The increased throughput and the minimization of the need for expensive lithography tools enable fast and cheap manufacture of many samples, and may significantly aid and accelerate research in the field of perovskite gain media.
Translated title of the contributionStrukturierung mittels Nanopräge-Lithografie für Perowskit-basierte Laser
Original languageEnglish
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Goldberg, Iakov, Supervisor (external), External person
  • Teichert, Christian, Supervisor (internal)
Award date31 Mar 2023
DOIs
Publication statusPublished - 2023

Bibliographical note

embargoed until 28-02-2024

Keywords

  • laser
  • photonics
  • nanoimprint lithography
  • perovskite
  • perovskite lasers
  • DFB
  • thin films
  • spin coating

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