本論文利用X光吸收光譜(X-ray absorption spectroscopy, XAS)、X光光電子能譜(X-ray photoelectron spectroscopy, XPS)及掃描式光電子能譜顯微術(Scanning photoelectron microscopy, SPEM)等技術來探討凝態材料的電子與原子結構，包括二氧化釕(RuO2)及二氧化銥(IrO2)奈米柱(nanorods)、藍青銅礦(K0.3MoO3)準一維材料及高密度的二氧化矽薄膜(SiO2 thin films)等。

在二氧化釕及二氧化銥奈米柱的研究中，因為釕d軌域其電子數相較於銥是較少以致影響其混成鍵結強度，使得二氧化銥其導電性質較二氧化釕為差;並且在二氧化釕的奈米柱尖端相較二氧化銥有更大的電子態密度，顯示二氧化釕奈米柱在場發射的應用上可預期是較好的材料。在藍青銅礦準一維材料中，利用同步輻射光的偏極性，發現在臨近電荷密度波(Charge-Density-Wave, CDW)相變點溫度時，K+離子的存在與其不同晶軸的電子結構和準一維系統之異向性有相當重要的關聯。高密度的二氧化矽薄膜中，由實驗結果觀察出不同的薄膜成長方式會導致不同密度的矽-氧混成鍵結而影響其電子結構，因此可以透過改變成長方法來提高二氧化矽薄膜中矽-氧的混成鍵結密度，並藉此調控其介電常數。

In this thesis, it is used the X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS) and scanning photoelectron microscopy (SPEM) to discuss the electronic and atomic structure of different condensed materials including RuO2 and IrO2 nanorods, quasi-one-dimension (1-D) blue bronze K0.3MoO3 and high-density SiO2 thin films.

In RuO2 and IrO2 nanorods research, the results reveal that the hybridization between O 2p and metal t2g obitals is weaker in IrO2 than in RuO2. The tip-region enhancement of the SPEM intensity is greater for RuO2 than for IrO2, which suggests that RuO2 be a better material for field emission application. In 1-D blue bronze K0.3MoO3 material, the existence of the K+ ion has play an important role to connect the MoO3 octahedral structure and maintain the anisotropy structure in the charge-density-wave (CDW) transition. In the high density SiO2 thin films, we discovered that the different growth processes will cause the vary Si–O bonding, therefore we can control the dielectric parameter by changing the growth method.

Acknowledgement…………………………………………………………………….i
Abstract……………………………………………………...……..………….……...ii
List of Tables..………………………………………………………………….……..v
List of Figures………………………………………………………………….……..v

Chapter 1.	Introduction………...………………………………………………...1
   
Chapter 2.	Experimental Techniques
2.1 Synchrotron Radiation……...........…………………..………….....…13
2.2 X-ray Spectroscopy......……………...….....………………..…...…….18
2.2.1 X-ray absorption spectroscopy (XAS)…………………………...18
2.2.2 X-ray photoelectron spectroscopy (XPS)……...………………...27
2.2.3 Scanning photoelectron microscopy (SPEM)...………………....29

Chapter 3.	Electronic Structure of RuO2 and IrO2 Nanorods
3-1 Overview………………………………………….….………………..30
3-2 Experimental….………………...…………………….………………31
3-3 Results………….…...............……………….…..…….………………31
3-4 Conclusion……….…………………...……………….……………….39  

Chapter 4.	Anisotropy in Quasi-one-dimensional (1-D) K0.3MoO3 Material
4-1 Overview….……………………………………….…………………..41
4-2 Experimental…………………………………………….……………42
4-3 Results……………..………………………………….…..……….…..43
4-4 Conclusion………………………………….…………….……………49

Chapter 5.	Enhancement of Si-O Structure of High Density SiO2 Film
5-1 Overview………………………...………………….………..………..51
5-2 Experimental…………….……………………………………………52
5-3 Results…………………………………………….…..………….……52
5-4 Conclusion…………………………………………………..…………60

Chapter 6.	Summary…………………...………...………………………...…....61

Bibliography…………………………………………………………….…………...63

List of Tables
Table I. Properties of transition-metal-dioxide compounds that form with rutile-type
structures. The note symbol M, S, F, and AF are identified the metals, semiconductors,
ferromagnets, and antiferromagnets, respectively……………………………………..2
List of Figures
1-1. Resistivity versus temperature of IrO2 and RuO2……...…..………...…..........4
1-2. Primitive unit cell for AB2 compounds with the rutile structure...…...…..........4
1-3. The crystal structure of the prototype blue bronze, K0.3MoO3; non-equivalent
Mo sites are denoted by Mo(1), Mo(2) and Mo(3). The zigzag chain structure
of K ions is also evident.………...………………………………………….....6
1-4. (a) The electric charge is tends to the equal-space assignment in room
temperature. (b) It will open a gap in Fermi surface when the CDW occurrence,
simultaneously produces the metal - semiconductor transition….………….....8
1-5. (a) Nonlinearity current-voltage curve. (b) Washing-board model for CDW
sliding…………………………………………………………....………….....9
1-6. Schematic structure of CMOS device...………………………....…………...11
1-7. Ball-and-stick model of the cubic SiO2 structure. The light and dark balls
represent Si and O atoms, respectively.....……………………....…………...12
2-1. Schematic diagram of the synchrotron radiation source…..………...….........14
2-2. Schematic diagram of the electromagnetic spectrum distributions.......…......15
2-3. Schematic diagram with different kinds of signal when synchrotron radiation
pass through the matters.……………………………………….………..…...17
2-4. The electron mean-free-path in solids as a function of the kinetic energy of the
electron.………………………………………………………..……..………17
2-5. A typical x-ray absorption spectrum showing the range of XANES and
EXAFS spectra.……...……………………………………...………..……....19
2-6. The photoelectron scattering process in the (a) multiple-scattering regime,
XANES and (b) single-scattering regime, EXAFS.……………….…….…...19
2-7. The schematic of various methods of measurements.………..........................23
2-8. Data reduction and data analysis in EXAFS spectroscopy: (a) EXAFS
spectrum χ(k) vs k after background removal, normalization, and E to k
conversion; (b) the solid curve is the weighted EXAFS spectrum k3χ(k) vs k.
The dashed curve is the fitting curve. (c) Fourier transformation (FT) of the
weighted EXAFS spectrum in momentum (k) space into distance space. The
dashed curve is the window function; (d) Fourier-fitted EXAFS spectrum
(solid curve) of the major peak in (c) after backtransforming into k space and
fit the filtered data shown in dashed curve……………..………….................26
2-9. The schematic of three-step XPS process.……………………….…..........…28
2-10. Schematic diagram of U5-SPEM system.………..…………..……………....29
3-1. X-ray diffraction patterns of RuO2 and IrO2 nanorods. Insets present SEM
images of nanorods; (a) IrO2, (b) RuO2 and (c) TEM picture of the IrO2
nanorod tip.…………………….......................................................................32
3-2. O K-edge XANES spectra of RuO2 and IrO2 nanorods. Upper inset presents
background corrected a* and b* features and the lower inset displays Ru and
Ir L3-edge XANES spectra.………………………............................……..…33
3-3. Fourier transform spectra of EXAFS k2χ data from k=3.5~11.5Å−1 at Ru Kand
Ir L3-edge of RuO2 and IrO2 nanorods. Inset shows EXAFS k2χ
oscillations... …………………………………………………………………36
3-4. Valence-band PES of RuO2 and IrO2 nanorods from selected regions of tip
(t1)-(t3) and sidewall (s1)-(s3), as displayed in SPEM images (upper insets).
The lower inset compares PES data from the tip regions of RuO2 and IrO2
nanorods.……………………………………………………………...…...…37
4-1. Normalized XANES spectra at the O K-edge measured at various angles and
along the b and d axes obtained at 140 K. The top inset presents the geometry
of measurement and the bottom inset magnifies the variation in spectral
features at various angles, θ=0, 40 and 700, and along the b and d
axes.……..……………………………………………………….…………...44
4-2. Normalized XANES spectra at the Mo L3-edge measured at various angles
and along the b and d axes obtained at 140 K. The inset magnifies the
variation in the 4d t2g and eg bands at various angles, θ=00, 400 and 700, and
along the b and d axes.……………………………………...………………..46
4-3. Normalized XANES spectra at the K K-edge measured at various angles and
along the b and d axes obtained at 140 K. The inset magnifies the variation in
spectral features at various angles, θ=00, 400 and 700, and along the b and d
axes.……………………………………….…………….……………………48
5-1. (a) Si L3,2- and (b) O K-edge XANES spectra of UV- and TH-SiO2 films. The
dotted line represents a best-fitted Gaussian background. The insets present
magnified features A, B and a, b and c, after background
subtraction.……………………..………………………………..…………...53
5-2. Valence-band photoemission spectra of UV- and TH-SiO2 films. The
valence-band of UV-SiO2 shown in the bottom is decomposed into four
Gaussian peaks, after the Gaussian base subtraction as shown in figure
(represented by a dotted line). The upper inset presents the molecular bonds in
the SiO2 tetrahedron.……………………...……………………………….….56
5-3. (a) and (b) show linear scans through the Bragg reflection (400) of the Si
substrate along the H and K directions for both UV- and TH-SiO2 films using
high resolution x-ray diffraction, respectively. The intensities are displayed on
a log-scale. The insets show the contour plots around the (400) of the Si
substrate in the H-K plane.………………………….……………………..…59

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