Figure 1.1. Schematic diagram of the pump-probe experiment setup. The relative time delay... 27

Figure 1.2. (a) Time-dependent diffracted intensity for (220) reflections. Red curves are... 28

Figure 1.3. Angular shift of (111) gold Bragg peak as a function of delay time from the same... 30

Figure 1.4. The melting dynamics of 2 nm Au nanoparticles. (Left) mRDF map constructed... 31

Figure 3.1. Schematic illustration of a transfer matrix in a trace space: Left side is an initial... 47

Figure 3.2. Schematic illustration of electron beam dynamics in drift/magnetic lens/drift... 48

Figure 3.3. Schemtic illustration of an image system with one lens. 51

Figure 3.4. The 6D emittance εxεyεz vs. the number of emitted electrons Nemit for the...[이미지참조] 58

Figure 4.1. RF-enabled high-brightness ultrafast electron beam system at Michigan State University 61

Figure 4.2. (a) Photoelectron pulse trajectory along an ultrafast electron beam column... 63

Figure 4.3. Cathode and anode of Pierce geometry photoelectron gun: (a) electric field cal-... 65

Figure 4.4. Pierce geometry photoelectron gun head assembly: (a) Fully assembled Pierce... 66

Figure 4.5. Pierce geometry photoelectron gun: (a) the whole Pierce photoelectron gun... 68

Figure 4.6. Current stability monitor (a) after the electron gun conditioning, (b) before the conditioning 71

Figure 4.7. Schematic illustration of non-uniform magnetic field (red lines) at the center... 72

Figure 4.8. Condenser magnetic lens No. 1: (a) The geometry of the lens. The yellow... 73

Figure 4.9. Condenser magnetic lens No. 2: (a) The geometry of the lens. The yellow... 74

Figure 4.10. Objective magnetic lens: (a) The geometry of the lens. The yellow box region... 75

Figure 4.11. (a) Magnetic lens current calibration simulation: Solid lines are AGM simulation... 78

Figure 4.12. Field Precision simulation of an electron trajectory with non-interacting par-... 80

Figure 4.13. Pillbox cavity with radius R and length d: (a) illustration of the pillbox ge-... 83

Figure 4.14. RF cavity: (a) The actual design of geometry optimized RF cavity and the... 87

Figure 4.15. Block diagram of the Phase lock loop. 89

Figure 4.16. Structure of charge coupled device (CCD) camera mount. (a) Schematic il-... 92

Figure 4.17. 266 nm excitation mirror holder and electron beam shield. 94

Figure 4.18. Electron beam deflector. (a) The design of the electron beam deflector: the... 97

Figure 4.19. Aperture manipulator. (a) Stereoscan 360 scanning electron microscope aper-... 98

Figure 4.20. Schematic diagram of the high-brightness UED chambers: (1) the 100 kV... 100

Figure 5.1. Schematic illustration of Faraday cup: To prevent the escape of an elastic scat-... 104

Figure 5.2. Single electron count events of attenuated electron beam on CCD camera. The... 106

Figure 5.3. (a) The probability profile of the integrated intensity of single-electron events.... 108

Figure 5.4. (a) The design of the beam trap. The copper tubing outer diameter is 2.0 mm... 109

Figure 5.5. The number of emitted electrons per pulse. (a) Simulation results of the number... 112

Figure 5.6. Illustration of the emittance measurement sheme 115

Figure 5.7. Electron beam image and profile on the CCD camera. (a) is a image of the full... 118

Figure 5.8. Electron beam trace space plot (x,x') of 10 electron per pulse and 106 electron...[이미지참조] 119

Figure 5.9. Dependence of the transverse emittance εx on the number of emitted electrons...[이미지참조] 120

Figure 5.10. (a) Schematic illustration for the beam propagation along the electron column... 123

Figure 5.11. Comparison between Field Precision trajectory simulation and experiment. (a)... 124

Figure 5.12. Schematic illustration of the phase jitter. (a) Perfect phase match between... 126

Figure 5.13. Beam size and energy variation of electron pulse with different relative phase... 128

Figure 6.1. Transient photoinduced charge redistribution near surface. (a) The three mech-... 134

Figure 6.2. Surface electron diffraction pattern in different conditions. (a) Ewald sphere... 137

Figure 6.3. The idealized slab model for considering the transient surface voltage. The top... 141

Figure 6.4. The refraction-induced shift (△B) for diffraction peak located at θO at VS＝1...[이미지참조] 143

Figure 6.5. Shadow imaging experiment to characterize the properties of photoemission. (a)... 147

Figure 6.6. N-particle shadow projection imaging simulation at two different time delays. 148

Figure 6.7. Experiments to characterize photoelectron dynamics and surface photovoltage... 150

Figure 6.8. (a) An effective circuit model depicting the transient surface voltage VS(t) mea-...[이미지참조] 153

Figure 6.9. Theoretical modeling of transient surface voltage VS(t). Using RC time of 30.8ps,...[이미지참조] 156

Figure 6.10. Transient surface voltage caused purely by △DP. △PE contribution is sub-... 158

Figure 7.1. Charge redistribution at nanomaterials interfaces subject to photoexcitation. (a)... 163

Figure 7.2. Trasient voltammetry from three diffracted beams from Si/SiO₂ interface, (a)... 167

Figure 7.3. (a) A sample of Au nanoparticles (NPs) immobilized on a functionalized Si... 171

Figure 7.4. (a) An effective circuit model depicting the transient surface voltage VS(t) mea-...[이미지참조] 172

Figure 7.5. Schematic illustration of localized surface plasmon oscillation induced by an oscil-... 175

Figure 7.6. Hollow gold nanoshell (HGN) surface plasmon resonance, (a) Schematic illus-... 180

Figure 7.7. An energy diagram of plasmon hybridization in a HGN describes the interaction... 182

Figure 7.8. Ultrafast transport at gold nanoparticle (NP)/SAM/silicon interface near surface... 183

Figure 7.9. (a) The statistics of HGNs diameter before fs laser irradiation and after irra-... 185

Figure 7.10. (a) Debye-Waller factor(DWF) analysis of the diffraction intensity drop. This... 189

Figure 8.1. CeTe₃ sample image on 1000 mesh TEM grid: (a) optical microscope image, (b)... 193

Figure 8.2. Convergent beam test to maximize the electron dose Ne/A. With the constant...[이미지참조] 196

Figure 8.3. (a) Convergent beam diffraction of TaS₂ with 50 μm aperture (exposure time 500... 198

Figure 8.4. (a) Crystal structure of VO₂ in metallic rutile phase: the gray ball is the V... 199

Figure 8.5. (a) Optical microscope image of VO₂ film sample which is grown on the 5 nm... 201

Figure 8.6. The photo-induced phase transition measurement with VO₂ with different RF... 203

Figure 8.7. Pulse duration measurement from VO₂ phase transition: VO₂ phase transition...[이미지참조] 204

Figure 8.8. (a) Electron pulse arriving time fluctuation during the experiment. Zero fluctu-... 206

Figure A.1. Different kinds of electrons scattering from the specimen 211

Figure A.2. Derivation of Bragg equation 2dsinθ＝nλ 213

Figure A.3. The phase angle difference of incident beam is k.r＝2πsinφ/λ and the path... 216

Figure A.4. Ewald sphere construction: The points are reciprocal lattice points of the crystal.... 218

Figure B.1. Ultrafast electron diffraction experiment geometry with ultrafast electron mi-... 223

Figure B.2. Schematic picture of the femtosecond laser source: (1) femtosecond seed pulse... 224

Figure B.3. Universal electron gun design. (a) Zoom-in of the electron gun head part,... 227

Figure B.4. Performance characterization of the 40 kV universal electron gun. (a) Analog-to-... 229

Figure B.5. Structure of charge coupled device (CCD) camera design. (a) Schematic illus-... 232

Figure E.1. (a) Schematic illustration of a non-interacting photoemission electron genera-... 240