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Title:Photonic crystal enhancement and tuning of quantum dot emission
Author(s):See, Gloria G.
Director of Research:Cunningham, Brian T
Doctoral Committee Chair(s):Cunningham, Brian T
Doctoral Committee Member(s):Alleyne, Andrew G; Goddard, Lynford; Gong, Songbin
Department / Program:Electrical & Computer Eng
Discipline:Electrical & Computer Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):photonic crystal
quantum dot
acoustic resonator
Radio frequency microelectromechanical system (RF MEMS)
tunable emission
replica molding
aluminum nitride
Abstract:The work presented in this dissertation demonstrates various methods and approaches for photonic crystals (PCs) to enhance the output emission and performance of quantum dots (QDs). We integrate visible wavelength emitting QDs within a polymer-based photonic crystal and excite them using an ultraviolet-emitting LED. The PC design incorporates two interleaved regions, each with distinct periods in orthogonal directions to enable simultaneous resonant coupling of ultraviolet excitation photons to the QDs and visible QD emission at two different wavelengths to efficiently extract photons normal to the PC surface. The combined excitation and extraction enhancements result in a 5.8X increase in the QD output intensity. Further, we demonstrate multiple QD-doped PCs combined on a single surface to optimally couple with distinct populations of QDs, offering a means for blending color output and directionality of multiple wavelengths. Another replica molded PC is fabricated with embedded QDs in which electrohydrodynamic jet printing is used to control the position of the quantum dots within the device structure. This results in significantly less waste of the QD material and the targeted placement of the quantum dots minimizes any emission outside of the resonant enhancement field, enabling an 8X output enhancement and highly polarized emission from the PC structure. We demonstrate a method for combining sputtered TiO2 deposition with liquid phase dip-coating of a QD layer that enables precise depth placement of QD emitters within a high-index dielectric film, using a PC slab resonator to demonstrate enhanced emission from the QDs when they are located at a specific depth within the film. The depth of the QDs within the PC is found to modulate the resonant wavelength of the PC as well as the emission enhancement efficiency, as the semiconducting material embedded within the dielectric changes its spatial overlap with the resonant mode. The first real-time tuning of PC-enhanced QD emission is successfully performed by fabricating QD embedded PCs on the surface of an acoustic MEMs resonator. As the RF modulation deforms the piezoelectric material of the resonator, the surface PC is also deformed. The coupling wavelength of the PC is modulated away from the QD emission wavelength, producing measurable variation in the output intensity of the QD emission. By tailoring the design and fabrication of QD-embedded PCs, significant improvements in device efficiency and production costs can be realized for utilizing QDs in lighting and display applications.
Issue Date:2016-01-29
Rights Information:Copyright 2016 Gloria See
Date Available in IDEALS:2016-07-07
Date Deposited:2016-05

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