TY - THES

T1 - Nanoimprint Lithography Patterning for Perovskite Based Lasers

AU - Leitner, Simon

N1 - embargoed until 28-02-2024

PY - 2023

Y1 - 2023

N2 - 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.

AB - 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.

KW - Laser

KW - Nanopräge-Lithografie

KW - Perowskite

KW - Perowskit-Laser

KW - DFB

KW - Dünnschicht

KW - Spin-Coating

KW - Photonics

KW - laser

KW - photonics

KW - nanoimprint lithography

KW - perovskite

KW - perovskite lasers

KW - DFB

KW - thin films

KW - spin coating

U2 - 10.34901/mul.pub.2023.38

DO - 10.34901/mul.pub.2023.38

M3 - Master's Thesis

ER -