Photonic Crystal Phosphors
광자결정 형광체

DC Field Value Language
dc.contributor.authorKyungtaek Min-
dc.description학위논문(박사)--서울대학교 대학원 :자연과학대학 물리·천문학부,2015. 8. 전헌수.-
dc.description.abstractPhotonic crystals (PCs) are photonic structures with periodically arranged index profiles. The periodicity of the PC results in a complex photonic band structure that may include a photonic band-gap (PBG), as a photonic counterpart of electronic energy band-gap under the periodic potential of a crystalline solid. Within the PBG wavelength range, light is prohibited to propagate through the PC structure. Meanwhile, photonic band-edge (PBE) modes possess many novel and unique properties. Group velocity of light with a PBE wavelength approaches zero, which makes its interaction with matter significantly stronger.
In phosphor materials, a wavelength conversion of light occurs; they absorb energy of pump photons and re-radiate photons typically at a longer wavelength. Such color-conversion phosphors have many important applications in the general lighting industry. The phosphor-capped white light-emitting devices using light-emitting diodes (LEDs) or laser diodes (LDs) as pumping sources are recent characteristic examples of next-generation light sources for solid-state lighting. Consequently, considerable efforts have been devoted to improve the luminous efficiency of phosphors. However, most developmental works for highly efficient phosphors have focused on material aspects, such as the synthesis and adoption of new chemicals, which improve the internal quantum efficiency (IQE) of phosphor materials.
In this thesis, I suggested a new concept of PC phosphors to enhance pumping efficiency for phosphor materials. Unlike any other methods for improvement of the IQE of phosphors or the extraction efficiency of emitted light from phosphors, I paid attention to the structural aspects of phosphors and increased concentration of pump photons in the structured phosphor media. More specifically, the electric field of the PBE modes is localized in the PC phosphors, which induces strong interaction between pump photons and phosphor materials. As directions of periodicity, such as vertical and lateral, two types of the PC phosphors were demonstrated in this thesis.
dc.description.tableofcontentsChapter 1
Introduction 1
1.1 Photonic Crystals 1
1.1.1 Introduction 1
1.1.2 Photonic crystals and electronic crystals 4
1.2 Phosphors 6
1.2.1 Luminous efficiency of phosphors 6
1.2.2 Photonic crystal phosphors 9
1.3 Computational Method 11
1.3.1 Plane-wave expansion method 11
1.3.2 Transfer-matrix method 12
1.3.3 Finite-difference time-domain method 13
1.4 Outline of the Manuscript 14
References 15

Chapter 2
Vertical Photonic Crystal Phosphor 17
2.1 Introduction 17
2.2 Model Calculation 19
2.2.1 Optical properties of vertical photonic crystals 21
2.2.2 Electric field profiles in vertical photonic crystal phosphors 23
2.2.3 Absorption enhancement factor 27
2.3 Sample Design and Fabrication 34
2.3.1 Sample design 36
2.3.2 Fabrication method 39
2.4 Measurements and Analyses 43
2.4.1 Measurement setup 43
2.4.2 Photoluminescence spectra 45
2.4.3 Photoluminescence enhancement factor 48
2.5 Summary 51
References 52

Chapter 3
Lateral Photonic Crystal Phosphor 55
3.1 Introduction 55
3.2 Model Calculation 58
3.2.1 Photonic band-edge modes of lateral 1D photonic crystals 60
3.2.2 Absorption enhancement 64
3.3 Sample Fabrication 68
3.3.1 Laser holographic lithography 68
3.3.2 Fabrication steps 70
3.4 Measurements and Analyses 74
3.4.1 Measurement setup 74
3.4.2 Photoluminescence enhancement 74
3.4.3 Polarization dependence of the photonic band-edge effect 78
3.5 Summary 82
References 83

Chapter 4
Conclusion 85

Abstract in Korean 87
dc.format.extentxii, 88-
dc.publisher서울대학교 대학원-
dc.subjectPhotonic crystal, Phosphor, Photonic crystal phosphor, Photonic band-edge, Quantum dot, Laser holographic lithography-
dc.titlePhotonic Crystal Phosphors-
dc.title.alternative광자결정 형광체-
dc.contributor.department자연과학대학 물리·천문학부-
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College of Natural Sciences (자연과학대학)Dept. of Physics and Astronomy (물리·천문학부)Physics (물리학전공)Theses (Ph.D. / Sc.D._물리학전공)
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