本論文主要探討利用垂直冷壁式有機金屬化學汽相沉積法(MOCVD)成長一維二氧化鈦(titanium dioxide; TiO2)奈米晶體及具金紅石結構之導電氧化物二氧化銥(iridium dioxide; IrO2)、二氧化釕(ruthenium dioxide; RuO2)與金紅石的異質奈米晶體。首先藉由不同成長條件在不同基板上成功沉積銳鈦礦(anatase)、金紅石(rutile)兩種不同結晶相之二氧化鈦奈米晶體，同時探討由低溫銳鈦礦晶相轉換成高溫金紅石晶相之退火(annealing)條件。此外以金紅石奈米晶體為基材成長二氧化銥或二氧化釕之異質奈米晶體。並探討銳鈦礦及金紅石兩種晶相之二氧化鈦一維奈米晶體與一維異質氧化物奈米晶體樣品之相關物性。利用拉曼散射(Raman scattering)分析晶體結晶相及結構相關訊息。場發射式電子顯微鏡(FESEM)、X光繞射(XRD)與穿透式電子顯微鏡(TEM)來深入探討晶體表面形貌與結晶方向。X光光子能譜(XPS)分析晶體化學鍵結與組成。光激發螢光光譜(PL)與表面光電壓光譜(SPS)研究二氧化鈦奈米晶體光學特性相關訊息。
我們於石英玻璃基板(fused silica)上成長具(220)優選方向之銳鈦礦晶相二氧化鈦一維奈米晶體，並探討其相關特性。利用X光光子能譜實驗分析得知其氧鈦比為2.0(誤差為±0.1)。經由表光電壓實驗觀察其光學間接能係為3.14 eV(誤差為±0.01 eV)。根據穿透式電子顯微鏡與其電子繞射圖(SAED)研究此(220)方向銳鈦礦二氧化鈦一維奈米晶體是由基本建構組織(building unit)沿著{112}群集面所組成，其成長機制主要是由連續週期性鍵結(PBC theory)藉由合適成長條件而呈現(220)優選方向銳鈦礦二氧化鈦一維奈米晶體。
接著有系統的研究退火對二氧化鈦結晶相轉換的效應。將550 °C條件下成長於藍寶石(sapphire; SA)(100)基板之銳鈦礦二氧化鈦一維奈米晶體，置於氧氣氛底下之高溫爐使用600、700、800、900、1000 °C條件做退火，隨後探討其影響。拉曼散射與X光繞射實驗可以得知其二氧化鈦結晶相會在退火溫度為800 °C時由銳鈦礦(220)優選方向轉換為金紅石優選(002)方向，並且當退火溫度高達900 °C就會呈現純金紅石二氧化鈦一維奈米晶體。由此可以得知當其退火溫度提高時不但可以轉換二氧化鈦之結晶相並且當退火溫度更高時(超過900 °C)可以得到品質更佳之純金紅石二氧化鈦一維奈米晶體。
此外利用不同成長條件在藍寶石SA(100)與(012)基板上成功沉積具有金紅石結晶相排列整齊之緻密二氧化鈦一維奈米晶體。在SA(100)基板上可以成長出沿[001]方向(c軸)的緻密排列二氧化鈦一維奈米晶體。界面晶格分析顯示，其奈米晶體與基板的晶軸關係為R-TiO2(001)//SA(100)與 R-TiO2(100)//SA(010)，但有趣的是當成長在(012)基板時卻會出現緻密排列一維奈米晶體以一傾斜角度(33°)成長出基板平面。拉曼散射可以確定其緻密排列一維奈米晶體為金紅石結晶相。穿透式電子顯微鏡及其電子繞射圖與X光繞射分析結果顯示，金紅石二氧化鈦是以磊晶方式成長於藍寶石SA(012)基板上並具有R-TiO2(101)//SA(012)與 R-TiO2(101)//SA(100)的晶向關係。金紅石二氧化鈦在藍寶石SA(012)基板具有(101)的起始凝核方向，便是造成會以一傾斜角度成長之因素，此與其基板應力有絕大密切之關係。
同時有系統性的探討兩種結晶相之二氧化鈦一維奈米晶體的光學特性。利用拉曼散射光譜確認其成長樣品均各自為純銳鈦礦與金紅石結晶相。經由光激發螢光實驗觀察銳鈦礦二氧化鈦，其光激發螢光來自於被六氧化鈦鍵結所自我捕捉之激子，這跟文獻中的銳鈦礦單晶結果相符。分析金紅石二氧化鈦之光激發螢光落於1.5與2.7 eV，其可見光光激發螢光光譜(2.7 eV)是來自於接近氧缺陷之六氧化鈦鍵結所自我捕捉之激子，此外靠近紅外光區域之激發螢光光譜(1.5 eV)是源自於金紅石二氧化鈦之本質缺陷。利用接近能隙之表面光電壓光譜來決定其銳鈦礦與金紅石二氧化鈦一維奈米晶體之間接能隙，分別為3.14 eV (誤差為±0.02 eV)、3.01 eV (誤差為±0.02 eV)。量測結果與文獻報導中之單晶數值接近。
利用適當成長條件將金紅石二氧化鈦奈米柱成長於藍寶石SA(100)基板，然後再將二氧化銥(二氧化釕)成長於金紅石二氧化鈦上成為異質奈米晶體。因二氧化銥(二氧化釕)的晶格常數與金紅石二氧化鈦相當接近，有利於異質奈米晶體之成長，進而觀察其相關特性。藉由拉曼散射與X光繞射確認二氧化銥(二氧化釕)有成功成長於金紅石二氧化鈦上。場發射式電子顯微鏡觀察二氧化銥(二氧化釕)皆以夾108度一維V型奈米楔(柱)呈現。不同的是在二氧化釕方面還會觀察到銜接金紅石二氧化鈦垂直方向(c軸)成長的二氧化釕奈米柱共存現象。利用穿透式電子顯微鏡與電子繞射圖分析出二氧化銥與二氧化釕是以共有(101)介面各自往(101)晶面沿[001]方向成長形成一維V型二氧化銥奈米楔(二氧化釕奈米柱)，此成長晶面與底層金紅石二氧化鈦一樣。其金紅石尖端結構、成長條件與(c軸)成長機制影響會形成V型單獨出現或是V型與垂直成長共存的二氧化銥(二氧化釕)奈米楔(柱)。

In this dissertation, we have studied the growth conditions for the deposition of well-aligned anatase (A) and rutile (R) phases titanium dioxide (TiO2) nanocrystals (NCs) as well as IrO2/R-TiO2 and RuO2/R-TiO2 hetero-nanocrystals on various substrates via the technique of cold-wall metal organic vapor deposition (MOCVD). The source reagents used for TiO2, IrO2 and RuO2 deposition are Ti(OC3H7)4, (C6H7)(C8H12)Ir and bis(ethylcyclopentadienyl) ruthenium (II), respectively. Thermal-induced phase transformation from A-TiO2 to R-TiO2 was also studied. A detailed characterization focusing on the surface morphology, structural, orientations, optical and spectroscopy properties of A- and R-TiO2 NCs, IrO2/R-TiO2 and RuO2/R-TiO2 hetero-nanocrystals have been carried out by means of field emission scanning electron microscopy (FESEM), X-ray diffractometry (XRD), micro-Raman scattering (RS), photoluminescence (PL), surface photovoltage spectroscopy (SPS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and selected-area electron diffractometry (SAED).
Under the growth condition of 1.5 mbar and 60 牵C(chamber pressure and showerhead temperature), we have successfully deposited well-aligned A-TiO2 NCs on fused silica with a preferential orientation of (220). Raman spectrum confirmed the deposition of pure anatase phase TiO2 on fused silica. Luminescence of self-trapped excitons and oxygen vacancies were observed in anatase NCs. The indirect band gap of A-TiO2 was determined to be 3.14 ± 0.01 eV by analyzing the surface photovoltage spectrum. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses showed oxygen vs. titanium ratio of 2.0 ± 0.1 for the as-deposited A-TiO2 NCs. Further structural characterization of the well-aligned A-TiO2 NCs was studied using TEM technique. The formation of building units bonded along {112} facets with preferred (220) orientation of the well-aligned A-TiO2 NCs on fused silica were presented and the probable growth mechanisms were discussed.
A detailed study of thermal-induced phase transformation in TiO2 NCs via XRD and RS spectroscopy has also been carried out. Vertically-aligned A-TiO2(220) NCs were grown on sapphire SA(100) substrate at 550 °C. The effects of thermal annealing of TiO2 NCs in oxygen atmosphere between 600 and 1000 °C were investigated. XRD and RS spectra showed the onset of the phase transformation process from the as-grown A-TiO2(220) NCs into R-TiO2(002) at the annealing temperature of 800 °C. At annealing temperature higher than 900 °C, pure R-TiO2(002) NCs were formed and the crystalline quality of TiO2 NCs can be further improved upon higher annealing temperature.
The well-aligned densely-packed R-TiO2 NCs have been grown on SA(100) and (012) substrates. FESEM micrographs revealed the growth of vertically aligned NCs on SA(100), whereas the NCs on SA(012) were grown with a tilt angle of ~ 33牵 from the normal to the substrates. TEM and SAED measurements showed that the TiO2 NCs on SA(100) have their long axis directed along the [001] direction. The XRD results revealed TiO2 NCs with (002) orientation on SA(100) substrate or (101) orientation on SA(012) substrate. A strong substrate effect on the alignment of the growth of TiO2 NCs has been demonstrated and the probable mechanism for the formation of these NCs has been discussed.
The optical characterization of well-aligned A- and R-TiO2 NCs grown on SA(100) substrate under different conditions have been carried out by using Raman scattering (RS), photoluminescence (PL) and surface photovoltage spectroscopy (SPS) techniques. Raman spectra confirmed the formation of pure phases of A- and R-TiO2. Comparing to the results of the single crystals, the luminescence features of A-TiO2 were assigned to the recombination of self-trapped excitons localized on TiO6 octahedra and oxygen vacancies. The emission spectrum of the R-TiO2 NCs contained features related to the visible- and near infrared-broad- bands centered on 1.5 and 2.7 eV, respectively. The visible band was attributed to the bound excitation emission due to the trapping of free excitons by TiO6 octahedra near oxygen vacancies and the near infrared band is associated with the emission centers of intrinsic defect in R-TiO2. The indirect band gaps for the as-grown A- and R-TiO2 NCs were estimated to be 3.14 ± 0.02 and 3.01 ± 0.02 eV, respectively, by analyzing near band edge surface photovoltage spectra.
The study of the growth of IrO2/R-TiO2 and RuO2/R-TiO2 hetero-nanocrystals has been carried out as well. The IrO2 /RuO2 NCs were grown on top of well-aligned R-TiO2 templates. The FESEM images and XRD patterns indicated growth of V-shaped IrO2(101) nanowedges (NWs)/coexistence of vertically aligned (002) and V-shaped RuO2(101) nanorods (NRs) on top of R-TiO2 NRs. TEM and SAED characterizations of V-shaped IrO2/RuO2 NCs showed crystalline IrO2 NWs/RuO2 NRs with a twin plane of (101) and twin direction of at the V-junction. The probable mechanisms for the formation of well-aligned IrO2 NWs/ RuO2 NRs were discussed.

[1] Wells, A. F., 1975, Structural inorganic chemistry, Clarendon press : Oxford.
[2] Okimura, K., 2001, “Low Temperature Growth of Rutile TiO2 Films in Modified RF Magnetron Sputtering,” Surf. Coat. Technol., Vol. 135, No. 2-3, pp. 286-290.
[3] Burgess, D. R., Anderson, T. J., Morris Hotsenpiller, P. A., and Hohman, J. L., 1996, “Solid Precursor MOCVD of Heteroepitaxial Rutile Phase TiO2,” J. Cryst. Growth, Vol. 166, No. 1, pp. 763-768.
[4] Sekiya, T., Ohta, S., Kamei, S., Hanakawa, M., and Kurita, S., 2001, “Raman Spectroscopy and Phase Transition of Anatase TiO2 under High Pressure,” J. Phys. Chem. Solids, Vol. 62, No. 4, pp. 717-721.
[5] Hossks, N., Sekiya, T., and Kurita, S., 1997, “Excitonic State in Anatase TiO2 Single Crystal,” J. Lumin., Vol. 72-74, pp. 874-875.
[6] Swamy, V., and Dubrovinsky, L. S., 2001, “Bulk Modulus of Anatase,” J. Phys. Chem. Solids, Vol. 62, No. 4, pp. 673-675.
[7] Parker, J. C., and Siegel, R. W., 1990, “Raman Microprobe Study of Nanophase TiO2 and Oxidation-Induced Spectral Changes,” J. Mater. Res., Vol. 5, No. 6, pp. 1246-1252.
[8] Mo, S. D., and Ching, W. Y., 1995, “Electronic and Optical Properties of Three Phases of Titanium Dioxide: Rutile, Anatase, and Brookite,” Phys. Rev. B, Vol. 51, No. 13, pp. 13023-13032.
[9] Lazzeri, M., Vittadini, A., and Selloni, A., 2001, “Structure and Energetics of Stoichiometric TiO2 Anatase Surfaces,” Phys. Rev. B, Vol. 63, No. 15, pp. 155409-155417.
[10] Albu, S. P., Ghicov, A., Macak, J. M., Hahn, R., and Schmuki, P., 2007, “Self-Organized, Free-Standing TiO2 Nanotube Membrane for Flow-through Photocatalytic Applications,” Nano Lett., Vol. 7, No. 5, pp. 1286-1289.
[11] Zhang, X., Jin, M., Liu, Z., Tryk, D. A., Nishimoto, S., Murakami, T., and Fujishima, A., 2007, “Superhydrophobic TiO2 Surfaces: Preparation, Photocatalytic Wettability Conversion, and Superhydrophobic− Superhydrophilic Patterning,” J. Phys. Chem. C, Vol. 111, No. 39, pp. 14521-14529.
[12] Armstrong, A. R., Armstrong, G., Canales, J., Garcia, R., and Bruce, P. G., 2005, “Lithium-Ion Intercalation into TiO2-B Nanowires,” Adv. Mater., Vol. 17, No. 7, pp. 862-865.
[13] Hashimoto, K., Irie, H., and Fujishima, A., 2005, “TiO2 Photocatalysis: A Historical Overview and Future Prospects,” Jpn. J. Appl. Phys. Part 1, Vol. 44, No. 12, pp. 8269-8285.
[14] Fujishima, A., Rao, T. N., and Tryk, D. A., 2000, “Titanium Dioxide Photocatalysis,” J. Photochem. Photobiol. C, Vol. 1, No. 1, pp. 1-21.
[15] Fujihara, K., Kumar, A., Jose, R., Ramakrishna, S., and Uchida, S., 2007, “Spray Deposition of Electrospun TiO2 Nanorods for Dye-Sensitized Solar Cell,” Nanotechnology, Vol. 18, No. 36, pp. 365709.
[16] Tan, B., and Wu, Y. Y., 2006, “Dye-Sensitized Solar Cells Based on Anatase TiO2 Nanoparticle/Nanowire Composites,” J. Phys. Chem. B, Vol. 110, No. 32, pp. 15932-15938.
[17] O’Regan, B., and Gratzel, M., 1991, “A Low-Cost, High-Efficiency Solar Cell Based on Dye-Sensitized Colloidal TiO2 Films,” Nature, Vol. 353, pp. 737-740.
[18] Francioso, L., Presicce, D. S., Epifani, M., Siciliano, P., and Ficarell, A., 2005, “Response Evaluation of TiO2 Sensor to Flue Gas on Spark Ignition Engine and in Controlled Environment,” Sen. Actuators B, Vol. 107, No. 2, pp. 563-571.
[19] Kolmakov, A., and Moskovits, M., 2004, “Chemical Sensing and Catalysis by One-dimensional Metal-oxide Nanostructures,” Annu. Rev. Mater. Res., Vol. 34, No. 1, pp. 151-180.
[20] Varghese, O. K., and Grimes, C. A., 2003, “Metal Oxide Nanoarchitectures for Environmental Sensing,” J. Nanosci. Nanotechnol., Vol. 3, No. 4, pp. 277-293.
[21] Garzella, C., Bontempib, E., Deperob, L. E., Vomieroc, A., Della, M. G., and Sberveglieria, G., 2003, “Novel Selective Ethanol Sensors: W/TiO2 Thin Films by Sol–Gel Spin-Coating,” Sens. Actuators B, Vol. 93, No. 1-3, pp. 495-502.
[22] Garzella, C., Comini, E., Tempesti, E., Frigeri, C., and Sberveglieri, G., 2000, “TiO2 Thin Films by a Novel Sol–Gel Processing for Gas Sensor Applications,” Sens. Actuators B, Vol. 68, No. 1-3, pp. 189-196.
[23] Sakhno, O. V., Goldenberg, L. M., Stumpe, J., and Smirnova, T. N., 2007, “Surface Modified ZrO2 and TiO2 Nanoparticles Embedded in Organic Photopolymers for Highly Effective and UV-Stable Volume Holograms,” Nanotechnology, Vol. 18, No. 10, pp. 105704.
[24] Rabady, R., and Avrutsky, I., 2005, “Titania, Silicon Dioxide, and Tantalum Pentoxide Waveguides and Optical Resonant Filters Prepared with Radio-Frequency Magnetron Sputtering and Annealing,” Appl. Opt., Vol. 44, No. 3, pp. 378-383.
[25] Richel, A., Johnson, N. P., and McComb, D. W., 2000, “Observation of Bragg Reflection in Photonic Crystals Synthesized from Air Spheres in a Titania Matrix,” Appl. Phys. Lett., Vol. 76, No. 14, pp. 1816-1818.
[26] JCPDS card no. 77-0441, International Centre for Diffraction Data, Newtown Square, PA, USA.
[27] JCPDS card no. 83-2243, International Centre for Diffraction Data, Newtown Square, PA, USA.
[28] Cerneaux, S., Xiong, X., Simon, G. P., Cheng, Y. B., and Spiccia, L., 2007, “Sol-Gel Synthesis of SiC-TiO Naanoparticles for Microwave Processing,” Nanotechnology, Vol. 18, No. 5, pp. 055708.
[29] Liu, D., and Yates, M. Z., 2007, “Fabrication of Size-Tunable TiO2 Tubes using Rod-Shaped Calcite Templates,” Langmuir, Vol. 23, No. 20, pp. 10333-10341.
[30] Miao, Z., Xu, D., Ouyang, J., Guo, G., Zhao, X., and Tang, Y., 2002, “Electrochemically Induced Sol−Gel Preparation of Single-Crystalline TiO2 Nanowires,” Nano Lett., Vol. 2, No. 7, pp. 717-720.
[31] Qourzal, S., Assabbane, A., and Ait-Ichou, Y., 2004, “Synthesis of TiO2 via Hydrolysis of Titanium Tetraisopropoxide and its Photocatalytic Activity on a Suspended Mixture with Activated Carbon in the Degradation of 2-Naphthol,” J. Photo. Chem. A, Vol. 163, No. 2, pp. 317-321.
[32] Zhang, W. F., Zhang, M. S., and Yin, Z., 2002, “Microstructures and Visible Photoluminescence of TiO2 Nanocrystals,” Phys. Status Solidi A, Vol. 179, No. 2, pp. 319-327.
[33] Kumar, S. A., Lo, P. H., and Chen, S. M., 2008, “Electrochemical Synthesis and Characterization of TiO2 Nanoparticles and their use as a Platform for Flavin Adenine Dinucleotide Immobilization and Efficient Electrocatalysis,” Nanotechnology, Vol. 19, pp. 255501(7pp).
[34] Wang, H., He, J., Boschloo, G., Lindström, H., Hagfeldt, A., and Lindquist, S. E., 2001, “Electrochemical Investigation of Traps in a Nanostructured TiO2 Film,” J. Phys. Chem. B, Vol. 105, pp. 2529–2533.
[35] Kim, C. S., Moon, B. K., Park, J. H., Chung, S. T., and Son, S. M., 2003, “Synthesis of Nanocrystalline TiO2 in Toluene by a Solvothermal Route,” J. Cryst. Growth, Vol. 254, pp. 405-410.
[36] Tavaresa, C. J., Marquesa, S. M., Reboutaa, L., Lanceros-Méndeza, S., Sencadasa, V., Costaa, C. M., Alvesb, E., and Fernandesc, A. J., 2008, “PVD-Grown Photocatalytic TiO2 Thin Films on PVDF Substrates for Sensors and Actuators Applications,” Thin Solid Films, Vol. 517, pp. 1161-1166.
[37] Wu, J. M., Shiha, H. C., and Wu, W. T., 2005, “Electron Field Emission from Single Crystalline TiO2 Nanowires prepared by Thermal Evaporation,” Chem. Phys. Lett., Vol. 413, No. 4-6, pp. 490-494.
[38] Wu, J. M., Wu, W. T., and Shih, H. C., 2005, “Characterization of Single-Crystalline TiO2 Nanowires Grown by Thermal Evaporation,” J. Electrochem. Soc., Vol. 152, No. 8, pp. G613-616.
[39] Wu, J. M., Shih, H. C., and Wu, W. T., 2005, “Growth of TiO2 Nanorods by Two-Step Thermal Evaporation,” J. Vac. Sci. Technol. B, Vol. 23, No. 5, pp. 2122-2126.
[40] Lőbl, P., Huppertz, M., Mergel, D., 1994, “Nucleation and Growth in TiO2 Films Prepared by Sputtering and Evaporation,” Thin Solid Films, Vol. 251, No. 1, pp. 72-79.
[41] Musil, J., Heřman, D., Šícha, J., 2006, “Low-Temperature Sputtering of Crystalline TiO2 Film,” J. Vac Sci. Technol A, Vol. 24, No. 3, pp. 521-528.
[42] Puddephatt, R. J., 1994, “Reactivity and Mechanism in the Chemical Vapor Deposition of Late Transition Metals,” Polyhedron, Vol. 13, No. 8, pp. 1233-1243.
[43] Maury, F., 1996, “Trends in Precursor Selection for MOCVD,” Chem. Vapor Depos., Vol. 2, No. 3, pp. 113-116.
[44] JCPDS card no. 15-0870, International Centre for Diffraction Data, Newtown Square, PA, USA.
[45] Ryden, W. D., Lawson, A. W., and Sartain, C. C., 1970, “Electrical Transport Properties of IrO2 and RuO2,” Phys. Rev. B, Vol. 1, No. 4, pp. 1494-1500.
[46] Cogan, S. F., Plante, T. D., McFadden, R. S., and Rauh, R. D., 1987, “Solar Modulation in a-WO3/a-IrO2 and c-KxWO3+(x/2)/a-IrO2 Complementary Electrochromic Windows,” Sol. Energy Mater., Vol. 16, pp. 371-382.
[47] Nishio, K., Watanabe, Y., and Tsuchiya, T., 1999, “Preparation and Properties of Electrochromic Iridium Oxide Thin Film by Sol-Gel Process,” Thin Solid Films, Vol. 350, No. 1-2, pp. 96-100.
[48] Osaka, A., Takatsuna, T., and Miura, Y., 1994, “Iridium Oxide Films via Sol-Gel Processing,” J. Non-Cryst. Solids, Vol. 178, pp. 313-319.
[49] Ioroi, T., Kitazawa, N., Yasuda, K., Yamamoto, Y., and Takenaka, H., 2000, “Iridium Oxide/Platinum Electrocatalysts for Unitized Regenerative Polymer Electrolyte Fuel Cells,” J. Electrochem. Soc., Vol. 147, No. 6, pp. 2018-2022.
[50] De Oliveira-Sousa, A., Da Silva, M. A. S., Machado, S. A. S., Avaca, L. A., and De Lima-Neto, P., 2000, “Influence of the Preparation Method on the Morphological and Electrochemical Properties of Ti/IrO2-Coated Electrodes,” Electrochim. Acta, Vol. 45, No. 27, pp. 4467-4473.
[51] Fog, A., and Buck, R. P., 1984, “Electronic Semiconducting Oxides as pH Sensors,” Sens. Actuators, Vol. 5, No. 2, pp. 137-146.
[52] Yao, S., Wang, M., and Madou. M., 2001, “A pH Electrode Based on Melt-Oxidized Iridium Oxide,” J. Electrochem. Soc., Vol. 148, No. 4, pp. H29-H36.
[53] Lue, J. C., and Chao, S., 1997, “Fabrication and Characterization of IrO2-Based Microsensors for Fast Detection of Carbon Dioxide,” Jpn. J. Appl. Phys. Part 1, Vol. 36, No. 4, pp. 2292-2297.
[54] Nakamura, T., Nakao, Y., Kamisawa, A., and Takasu, H., 1997, “Preparation of Pb(Zr, Ti)O3 Thin Films on Ir and IrO2 Electrodes,” Jpn. J. Appl. Phys. Part 1, Vol. 33, No. 9B, pp. 5207-5210.
[55] Nakamura, T., Nakao, Y., Kamisawa, A., and Takasu, H., 1994, “Preparation of Pb(Zr, Ti)O3 Thin Films on Electrodes including IrO2,” Appl. Phys. Lett., Vol. 65, No. 12, pp. 1522-1524.
[56] Jo, W., Cho, S. M., Lee, H. M., Kim, D. C., and Bu, J. U., 1999, “Effect of Oxygen to Argon Ratio on Growth of Bi4Ti3O12 Thin Films on Ir and IrO2 Prepared by Radio-Frequency Magnetron Sputtering,” Jpn. J. Appl. Phys. Part 1, Vol. 38, No. 5A, pp. 2827-2830.
[57] Hackwood, S., Schiavone, L. M., Dautremont-Smith, W. C., and Beni, G., 1981, “Anodic Evolution of Oxygen on Sputtered Iridium Oxide Films,” J. Electrochem. Soc., Vol. 128, No. 12, pp. 2569-2573.
[58] Sanjines, R., Aruchamy, A., and Levy, F., 1989, “Thermal Stability of Sputtered Iridium Oxide Films,” J. Electrochem. Soc., Vol. 136, No. 6, pp. 1740-1743.
[59] Pickup, P. G., and Birss, V. I., 1988, “The Influence of the Aqueous Growth Medium on the Growth Rate, Composition, and Structure of Hydrous Iridium Oxide Films,” J. Electrochem. Soc., Vol. 135, No. 1, pp. 126-133.
[60] Belova, I. D., Varlamova, T. V., Galyamov, B. Sh., Roginskaya, Yu. E., R. Shifrina, R., Prutchenko, S. G., Kaplan, G. I., and Sevostyanov, M. A., 1988, “The Composition, Structure and Electronic Properties of Thermally Prepared Iridium Dioxide Films,” Mater. Chem. Phys., Vol. 20, No. 1, pp. 39-64.
[61] Music, S., Popovic, S., Maljkovic, M., Skoko, Z., Furic, K., and Gajovic, A., 2003, “Thermochemical Formation of IrO2 and Ir,” Mater. Lett., Vol. 57, No. 29, pp. 4509-4514.
[62] Puddephatt, R. J., 1994, “Reactivity and Mechanism in the Chemical Vapor Deposition of Late Transition Metals,” Polyhedron, Vol. 13, No. 8, pp. 1233-1243.
[63] Maury, F., 1996, “Trends in Precursor Selection for MOCVD,” Adv. Mater., Vol. 8, No. 5, pp. 113-115.
[64] JCPDS card no. 21-1172, International Centre for Diffraction Data, Newtown Square, PA, USA.
[65] Krusin-Elbaum, L., and Wittmer, M., 1988, “Conducting Transition Metal Oxides: Possibilities for RuO2 in VLSI Metallization,” J. Electrochem. Soc., Vol. 135, No. 10, pp. 2610-2614.
[66] Kolawa, E., So, F. C. T., Pan, E. T. S., and Nicolet, M. S., 1987, “Reactively Sputtered RuO2 Diffusion Barriers,” Appl. Phys. Lett., Vol. 50, No. 13, pp. 854-855.
[67] Prudenziati, M., Morten, B., Cilloni, F., and Ruffi, G., 1989, “Very High Strain Sensitivity in Thick Film Resistors: Real and False Super Gauge Factors,” Sens. Actuators, Vol. 19, No. 4, pp. 401-414.
[68] Dziedzic, A., Golonka, L., and Mater., J., 1988, “Electrical Properties of Conductive Materials used in Thick-Film Resistors,” Sci., Vol. 23, No. 9, pp. 3151-3155.
[69] Jia, Q. X., and Anderson, W. A., 1990, “Sputter Deposition of YBa2Cu3O7−x Films on Si at 500 °C with Conducting Metallic Oxide as a Buffer Layer,” Appl. Phys. Lett., Vol. 57, No. 3, pp. 304-306.
[70] Norga, G. J., Fe, L., Wouters, D. J., and Maes, H. E., 2000, “Effect of RuO2 Growth Temperature on Ferroelectric Properties of RuO2/Pb(Zr, Ti)O3/RuO2/Pt Capacitors,” Appl. Phys. Lett., Vol. 76, No. 10, pp. 1318-1320.
[71] Lee, J. H., Kim, J. Y., and Rhee, S. W., 1999, “Chemical Vapor Deposition of RuO2 Thin Films using the Liquid Precursor Ru(OD)3,” Electrochem. Solid State Lett., Vol. 2, No. 12, pp. 622-623.
[72] Liao, P. C., Mar, S. Y., Ho, W. S., Huang, Y. S., and Tiong, K. K., 1996, “Characterization of RuO2 Thin Films Deposited on Si by Metal-Organic Chemical Vapor Deposition,” Thin Solid Films, Vol. 287, No. 1-2, pp. 74-79.
[73] Sakiyama, K., Onishi, S., Lshihara, K., Orita, K., Kajiyama, T., Hosoda, N., and Hara, T., 1993, “Deposition and Properties of Reactively Sputtered Ruthenium Dioxide Films,” J. Electrochem. Soc., Vol. 140, No. 12B, pp. 834-839.
[74] Kang, T. S., Kim, Y. S., and Je, J. H., 2000, “Thermal Stability of RuO2, BaxSr1-xTiO3/RuO2, and BaxSr1-xTiO3/Pt/Ti/SiO2 on Si(100),” J. Mater. Res., Vol. 15, pp. 1955-1961.
[75] Huang, Y. S., and Liao, P. C., 1998, “Preparation and Characterization of RuO2 Thin Films,” Sol. Energy Mater. Sol. Cells, Vol. 55, pp. 179-197.
[76] Gao, Y., Bai, G., Liang, Y., Dunham, G. C., and Chambers, S. A., 1997, “Structure and Surface Morphology of Highly Conductive RuO2 Films Grown on MgO by Oxygen-Plasma-Assisted Molecular Beam Epitaxy,” J. Mater. Res., Vol. 12, No. 7, pp. 1844-1849.
[77] Jia, Q. X., Wu, X. D., Foltyn, S. R., Findikoglu, A. T., Tiwari, P., Zheng, J. P., and Jow, T. R., 1995, “Heteroepitaxial Growth of Highly Conductive Metal Oxide RuO2 Thin Films by Pulsed Laser Deposition,” Appl. Phys. Lett., Vol. 67, No. 12, pp. 1677-1679.
[78] Bhaskar, S., Dobal, P. S., Majumder, S. B., and Katiyar, R. S., 2001, “X-ray Photoelectron Spectroscopy and Micro-Raman Analysis of Conductive RuO2 Thin Films,” J. Appl. Phys., Vol. 89, No. 5, pp. 2987-2992.
[79] Xia, Y., Yang,P., Sun, Y., Wu, Y., Mayers, B., Gates, B., Yin, Y., Kim, F., and Yan, H., 2003, “One-Dimensional Nanostructures: Synthesis, Characterization, and Applications,” Adv. Mater., Vol. 15, No. 5, pp. 353-389.
[80] Rao, C. N. R., Govindaraj, A., 2005, Nanotubes and Nanowires, Royal Society of Chemistry, London.
[81] Patzke, G. R., Krumeich, F., and Nesper, R., 2002, “Oxidic Nanotubes and Nanorods – Anisotropic Modules for a Future Nanotechnology,” Angew. Chem. Int. Ed., Vol. 41, No. 14, pp. 2446-2461.
[82] Baughman, R. H., Zakhidov, A. V., De Heer, W. A., 2002, “Carbon Nanotubes-the Route Toward Applications,” Science, Vol. 297, pp. 787-792.
[83] Chen, R. S., Huang, Y. S., Liang, Y. M., Hsiech, C. S., Tsai, D. S., Tiong, and K. K., 2004, “Field Emission from Vertically Aligned Conductive IrO2 Nanorods,” Appl. Phys. Lett., Vol. 84, pp. 1552-1554.
[84] Senda, S., Sakai, Y., Mizuta, Y., Kita, S., and Okuyama, F., 2004, “Super-Miniature X-ray Tube,” Appl. Phys. Lett., Vol. 85, pp. 5679-5681.
[85] Sander, M. S., Côté, M. J., Gu, W., Kile, B. M., and Tripp, C. P., 2004, “Template-Assisted Fabrication of Dense, Aligned Arrays of Titania Nanotubes with Well-Controlled Dimensions on Substrates,” Adv. Mater., Vol. 16, pp. 2052-2057.
[86] Cheng, K. W., Lin, Y. T., Chen, C. Y., Hsiung, C. P., Gan, J. Y., Yeh, J. W., Hsieh, C. H., and Chou, L. J., 2006, “In Situ Epitaxial Growth of TiO2 on RuO2 Nanorods with Reactive Sputtering,” Appl. Phys. Lett., Vol. 88, No. 4, pp. 043115-043118.
[87] Han, S., Li, C., Liu, Z., Lei, B., Zhang, D., Jin, W., Liu, X., Tang, T., and Zhou, C., 2004, “Transition Metal Oxide Core−Shell Nanowires: Generic Synthesis and Transport Studies,” Nano Lett., Vol. 4, No. 7, pp. 1241-1246.
[88] Zhang, D., Liu, Z., Han, S., Li, C., Lei, B., Stewart, M. P., Tour, J. M., and Zhou, C., 2004, “Magnetite (Fe3O4) Core−Shell Nanowires: Synthesis and Magnetoresistance,” Nano Lett., Vol. 4, No. 11, pp. 2151-2155.
[89] Chen, C. A., Chen, Y. M., Korotcov, A., Huang, Y. S., Tsai, D. S., and Tiong, K. K., 2008, “Growth and Characterization of Well-Aligned Densely-Packed Rutile TiO2 Nanocrystals on Sapphire Substrates via Metal–Organic Chemical Vapor Deposition,” Nanotechnology, Vol. 19, No. 7, pp. 075611-075614.
[90] Chen, R. S., Korotcov, A., Huang, Y. S., and Tsai, D. S., 2006, “One-Dimensional Conductive IrO2 Nanocrystals,” Nanotechnology, Vol. 17, No. 9, pp. R67-R87.
[91] Chen, R. S., Huang, Y. S., Tsai, D. S., Wu, C. T., Lan, Z. H., and Chen, K. H., 2004, “Growth of Well Aligned IrO2 Nanotubes on LiTaO3 (012) Substrate,” Chem. Matt., Vol. 16, No. 12, pp. 2457-2462.
[92] Chen, C. C., Chen, R. S., Tsai, T. Y., Huang, Y. S., Tsai, D. S., and Tiong, K. K., 2004, “The Growth and Characterization of Well Aligned RuO2 Nanorods on Sapphire Substrates,” J. Phys.: Conden. Matter, Vol. 16, No. 47, pp. 8475-8484.
[93] Wang, G., Hsieh, C. S., Tsai, D. S., Chen, R. S., and Huang, Y. S., 2004, “Area-Selective Growth of Ruthenium Dioxide Nanorods on LiNbO3(100) and Zn/Si Substrates,” J. Mater. Chem., Vol. 14, No. 24, pp. 3503-3508.
[94] Chueh, Y. L., Hsieh, C. H., Chang, M. T., Chou, L. J., Lao, C. S., Song, H., Gan, J. Y., and Wang Z. L., 2006, “RuO2 Nanowires and RuO2/TiO2 Core/Shell Nanowires: From Synthesis to Mechanical, Optical, Electrical, and Photoconductive Properties,” Adv. Mater., Vol. 19, No. 1, pp. 143-149.
[95] Ahn, Y. R., Park, C. R., Jo, S. M., and Kim, D. Y., 2007, “Enhanced Charge-Discharge Characteristics of RuO2 Supercapacitors on Heat-Treated TiO2 Nanorods,” Appl. Phys. Lett., Vol. 90, pp. 122106-122108.
[96] Chu, S. Z., Wada, k., Inoue, S., Hishita, S. I., and Kurashima, K., 2003, “Fabrication and Structural Characteristics of Ordered TiO2-Ru-(RuO2) Nanorods in Porous Anodic Alumina Films on ITO/Glass Substrate,” J. Phys. Chem. B, Vol. 107, pp. 10180-10184.
[97] Thermo VG Scientific: Avantage Software, West Sussex, England.
[98] Aigouy, L., Pollark, F. H., Petruzzello, J., and Shahzad, K., 1997, “Observation of Excitonic Features in ZnSe/ZnMgSSe Multiple Quantum Wells by Normalized Kelvin Probe Spectroscopy at Low Temperatures,” Solid State Commun., Vol. 102, No. 12, pp. 877-882.
[99] Adamowicz, B., and Szuber, J., 1991, “Near-Band Gap Transitions in the Surface Photovoltage Spectra for GaAs, GaP and Si Surfaces,” Surf. Sci., Vol. 247, No. 2-3, pp. 94-99.
[100] Kronik, L., and Shapira, Y., 1999, “Surface Photovoltage Phenomena: Theory, Experiment, and Applications,” Surf. Sci. Rep., Vol. 37, No. 1-5, pp. 1-206.
[101] Huang, Y. S., Malikova, L., Pollak, F. H., Shen, H., Pamulapati, P., and Newman, P., 2000, “Surface Photovoltage Spectroscopy, Photoreflectance, and Reflectivity Characterization of an InGaAs/GaAs/GaAlAs Vertical-Cavity Surface-Emitting Laser Including Temperature Dependence,” Appl. Phys. Lett., Vol. 77, No. 1, pp. 37-39.
[102] Wyckoff , R. W. G., 1965, Crystal Structures., Interscience Publishers, New York.
[103] Loudon, R., 1964, “The Raman Effect in Crystals,” Adv. Phys., Vol. 13, No. 50, pp. 423-482.
[104] Ohsaka, T., Izumi, F., and Fujiki, Y., 1978, “Raman Spectrum of Anatase, TiO2,” J. Raman Spectrosc., Vol. 7, No. 6, pp. 321-323.
[105] Bourgeois, S., Seigneu, P. Le., and Perdereau, M., 1995, “Study by XPS of Ultra-Thin Nickel Deposits on TiO2(100) Supports with Different Stoichiometries,” Surf. Sci., Vol. 328, No. 1-2, pp. 105-110.
[106] Hua, G. Y., Cheng, H. S., Shi, Z. Q., Jin, Z., Gang, L., Sean, C. S., Hui, M. C., and Gao, Q. L., 2008, “Anatase TiO2 Single Crystals with a Large Percentage of Reactive Facets,” Nature, Vol. 453, No. 7195, pp. 638-641.
[107] Silversmit, G., Doncker, G. D., and Gryse, R. D., 2002, “A Mineral TiO2 (001) Anatase Crystal Examined by XPS,” Surf. Sci. Spect., Vol. 9, pp. 21-29.
[108] Göpel, W., Anderson, J. A., Frankel, D., Jaenig, M., Phillips, K., Schäffer, J. A., and Rocker, G., 1984, “Surface Defects of TiO2(110): A Combined XPS, XAES and ELS Study,” Surf. Sci., Vol. 139, No. 2-3, pp. 333-346.
[109] Stefanov, P., Shipochka, M., Stefchev, P., Raicheva, Z., Lazarova, V., and Spassov, L., 2008, “XPS Characterization of TiO2 Layers Deposited on Quartz Plates,” J. Phys. : Conference Series, Vol. 100, pp. 012039-012043.
[110] Betz, G., and Wehner, G. K., 1983, Sputtering by Particle Bombardment II, in: R. Behrisch (Ed.), Topics in Applied Physics Springer-Verlag, Berlin.
[111] Tang, H., Berger, H., Schmid, P., and Levy, F., 1993, “Photoluminescence in TiO2 Anatase Single Crystals,” Solid State Commun., Vol. 87, No. 9, pp. 847-850.
[112] Saraf, L. V., Patil, S. I., Ogale, S. B., Sainkar, S. R., and Kshirsager, S. T., 1998, “Synthesis of Nanophase TiO2 by Ion Beam Sputtering and Cold Condensation Technique,” Int. J. Mod. Phys. B, Vol. 12, No. 25, pp. 2635-2647.
[113] Serpone, N., Lawless, D., and Khairutdinov, R., 1995, “Size Effects on the Photophysical Properties of Colloidal Anatase TiO2 Particles-Size Quantization or Direct Transitions in this Indirect Semiconductor”, J. Phys. Chem., Vol. 99, No.45, pp. 16646-16654.
[114] Sekiya, T., Kamei, S., and Kurita, S., 2000, “Luminescence of Anatase TiO2 Single Crystals Annealed in Oxygen Atmosphere”, J. Lumin., Vol. 87-89, pp. 1140-1142.
[115] Wu, J. M., Shin, H. C., Wu, W. T., Tseng, Y. K., and Chen, I. C., 2005, “Thermal Evaporation Growth and the Luminescence Property of TiO2 Nanowires”, J. Cryst. Growth, Vol. 281, pp. 384-390.
[116] Dumitras, Gh., Riechert, H., Porteanu, H., and Koch, F., 2002, “Surface Photovoltage Studies of InxGa1-xAs and InxGa1-xAs1-yNy Quantum Well Structures,” Phys. Rev. B, Vol. 66, No. 20, pp. 205324-205331.
[117] Hosaka, N., Sekiya, T., and Kurita, S., 1997, “Excitonic State in Anatase TiO2 Single Crystal,” J. Lumin., Vol. 72-74, pp. 874-875.
[118] Hartman, P., 1973, Crystal Growth: An Introduction, North Holland Publishing Company Amsterdam, London.
[119] Sunagawa, I., 1987, Morphology of Crystals, Terra Scientific Publishing Company: Tokyo.
[120] Kim, B., Byun, D., Lee, J. K., and Park, D., 2001, “Structural Analysis on Photocatalytic Efficiency of TiO2 by Chemical Vapor Deposition,” Jpn. J. Appl. Phys., Vol. 41, No. 1, pp. 222-226.
[121] Penn, R. L., and Banfield, J. F., 1998, “Imperfect Oriented Attachment: Dislocation Generation in Defect-Free Nanocrystals,” Science, Vol. 281, pp. 969-971.
[122] Zhang, Q., Liu, S. J., and Yu, S. H., 2009, “Recent Advances in Oriented Attachment Growth and Synthesis of Functional Materials: Concept, Evidence, Mechanism, and Future,” J. Mater. Chem., Vol. 19, pp. 191-207.
[123] Adachi, M., Murata, Y., Takao, J., Jiu, J., sakamoto, M., and Wang, F., 2004, “Highly Efficient Dye-Sensitized Solar Cells with a Titania Thin-Film Electrode Composed of a Network Structure of Single-Crystal-Like TiO2 Nanowires Made by the “Oriented Attachment” Mechanism,” J. Am. Chem. Soc., Vol. 126, pp. 14943-14949.
[124] Won, D. J., Wang, C. H., Jang, H. K., and Choi, D. J., 2001, “Effects of Thermally Induced Anatase-to-Rutile Phase Transition in MOCVD-Grown TiO2 Films on Structural and Optical Properties,” Appl. Phys. A, Vol. 73 pp. 595-600.
[125] Kim, C. S., Nakaso, K., Xia, B., Okuyama, K., and Shimada, M., 2005, “A New Observation on the Phase Transformation of TiO2 Nanoparticles Produced by a CVD Method,” Aerosol Sci. Technol., Vol. 39, No. 2, pp. 104-112.
[126] Gouma, P. I., and Mills, M. J., 2001, “Anatase-to-Rutile Transformation in Titania Powders,” J. Am. Ceram. Soc., Vol. 84, No. 3, pp. 619-622.
[127] Sun, Y., Egawa, T., Zhang, L., and Yao, X., 2002, “High Anatase-Rutile Transformation Temperature of Anatase Titania Nanoparticles Prepared by Metalorganic Chemical Vapor Deposition,” Jpn. J. Appl. Phys., Vol. 41, No. 8B, pp. L945-L948.
[128] Battiston, G. A., Gerbasi, R., and Porchia, M., 2004, “Influence of Substrate on Structural Properties of TiO2 Thin Films Obtained via MOCVD,” Thin Solid Films, Vol. 239, No. 2, pp. 186-191.
[129] Wiggins, M. D., Nelson, M. C., and Aita, C. R., 1996, “Phase Development in Sputter Deposited Titanium Dioxide,” J. Vac. Sci. Technol. A, Vol. 14, No. 3, pp. 772-776.
[130] Loudon, R., 1964, “The Raman Effect in Crystals,” Adv. Phys., Vol. 13, No. 50, pp. 423-482.
[131] Porto, S. P. S., Fleury, P. A., and Damen, T. C., 1967, “Raman Spectra of TiO2, MgF2, ZnF2, FeF2, and MnF2,” Phys. Rev., Vol. 154, No. 2, pp. 522-526.
[132] Korotcov, A. V., Huang, Y. S., Tiong, K. K., and Tsai, D. S., 2007, “Raman Scattering Characterization of Well-Aligned RuO2 and IrO2 Nanocrystals,” J. Raman. Spectrosc., Vol. 38, pp. 737-749.
[133] Haart L. G. L., and Blasse, G., 1986, “The Observation of Exciton Emission from Rutile Single Crystals,” J. Solid State Chem., Vol. 61, pp. 135-136.
[134] Miao lei, Tanemura, S., Toh, S., Kaneko, K., and Tanemura, M., 2004, “Fabrication and Photoluminescence of Rutile-TiO2 Nanorods,” J. J. Appl. Phys., Vol. 43, No. 10, pp. 7342-7345.
[135] Poznyak S. K., Sviridov, V., Kulak, A., and Smatsov, M. P., 1992, “Photoluminescence and Electroluminescence at the TiO2-Electrolyte Interface,” J. Electroanal. Chem., Vol. 340, No. 1-2, pp. 73-97.
[136] Mochizuki S., Shimizu, T., and Fujishiro, F., 2003, “Photoluminescence Study on Defects in Pristine Anatase and Anatase-Based Composites,” Physica B, Vol. 340-342, pp. 956-959.
[137] Fermandez I., and Cremades, A., 2005, “Cathodoluminescence Study of Defects in Deformed (110) and (100) Surfaces of TiO2 Single Crystals,” J. Semicond. Sci. Technol., Vol. 20, No. 2, pp. 239-243.
[138] Serpone N., Lawless, D., and Khairutdinov, R., 1995, “Size Effects on the Photophysical Properties of Colloidal Anatase TiO2 Particles-Size Quantization or Direct Transitions in this Indirect Semiconductors,” J. Phys. Chem., Vol. 99, No. 45, pp. 16646-16654.
[139] Korotcov, A., Hsu, H. P., Huang, Y. S., Tsai, D. S., and Tiong, K. K., 2006, “Growth and Characterization of Well-Aligned RuO2 Nanocrystals on Oxide Substrates via Reactive Sputtering,” Cryst. Growth Des., Vol. 6, No. 11, pp. 2501-2506.