ICMCTF2007 Session CP: Symposium C Poster Session

Thursday, April 26, 2007 5:00 PM in Room Town & Country
Thursday Afternoon

Time Period ThP Sessions | Topic C Sessions | Time Periods | Topics | ICMCTF2007 Schedule

CP-1 In-Situ Spectroscopic Ellipsometry for Perylene-3, 4, 9, 10-Tetracarboxylic Dianhydride/Copper Phthalocyanine in Organic Molecular Beam Deposition
K. Seo, H. Cooper, C. Bonner (Norfolk State University)
Organic epilayers of perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTCDA) and copper phthalocyanine (CuPc) were prepared by organic molecular beam deposition in high vacuum on indium-tin-oxide (ITO) with slide glass. The substrates were kept at room temperature during the deposition. The optical response of the multilayered structure was investigated by means of spectroscopic ellipsometry in the spectral between 1.5 to 4.5 eV. We use grazing incidence x-ray scattering to study the molecular structure and morphology of thin crystalline films.
CP-2 Second Harmonic Generation in Periodically Poled LiNbO3 Waveguides
S.W. Kwon (Hankuk Aviation University, Korea); W.S. Yang, W.K. Kim, H.M. Lee (Korea Electronics Technology Institute, Korea); Y.S. Song (Hankuk Aviation University, Korea); B.Y. Kim (University of Incheon, Korea); D.Y. Lee (Daelim College of Technology, Korea)
Periodically poled LiNbO3 (PPLN) was fabricated with a 7.3 um domain-inverted period, a 1.5 um thick photoresist grating (PR) and a 3 um pattern open width through the electric field poling process using the liquid electrode technique. After slicing the wafers to a final dimension of 30-10 mm2, the specimen was poled and then annealed. Second harmonic generation (SHG) in the visible (green) was investigated to obtain high domain inversion efficiencies. The fundamental and second harmonic waves of a 7.3 um PPLN waveguide were 1087-1 nm and 544-0.5 nm, respectively. The average duty cycle of the etched PPLN was estimated by using an optical microscope to be 50.6-3.3%. Detailed analysis will be discussed.
CP-3 Effects of MPII-Implanted Titanium on the Electrochromic Properties of Tungsten Trioxide Film
K.-W. Weng (Mingdao University, Taiwan); S. Han (National Taichung Institute of Technology, Taiwan); Y.-C. Chen (National Tsing Hua University, Taiwan); T.-N. Yuan (National Taichung Institute of Technology, Taiwan); D.-Y. Wang (Mingdao University, Taiwan)
There are great interests in electrochromic technology for smart windows and displays over the last decade. The substrate, a conductive glass being coated indium tin oxide (ITO) thin films, deposited tungsten trioxide (WO3) using radio frequency (RF) sputtering and implanted Ti by metal plasma ion implanter (MPII) in this study. The optimal fabrication conditions of the low implanted does and the high accelerating voltage exhibit excellent performance of electrochromic property. The improvement resulted from the effect of implanting Ti has been tested successfully, such as optical density (OD) close to 1.6, transmission modulation close to 1.3 and the response time during the colored and bleached state reducing 0.3.
CP-4 The Characterization of Nano-Copper Oxide Thin Films
H.-Y. Chen (National Kaohsiung University of Applied Sciences, Taiwan); S. Han (National Taichung Institute of Technology, Taiwan)
Nano-copper oxide films were prepared by magnetron sputtering associated with post-annealing. Nano-copper metal films were firstly deposited on glass substrate with a strong (111) preferred orientation. After that, the films were annealed in air at 200-500°C for 1 and 12 h. The annealed films became transparent with a reddish colour at 500°C for 2 and 12 h. The X-ray diffraction and Raman spectra shown that only copper (II) oxide phase was identified. The nano-granular morphology with the granular structure was observed at such annealing temperature. The direct optical band gap was deduced to be 1.3 eV by Tauc's plot in UV-Vis spectrum. The oxide film microstructure correlates to the optical and electrical properties is further investigated.
CP-5 Photo-Induced Hydrophilicity of TiO2-xNx Coated PET Plates
H.-Y. Chou, E.-K. Lee, J.-W. You (Ta-Hwa Institute of Technology, Taiwan); S.-S. Yu (National Chiao Tung University, Taiwan)
The nitrogen-doped thin films were prepared on PET (polyethylene terephthalate) plates using sputtering method with TiN target under a N2/O2 gas mixture, without heating temperature. The anatase phase of thin films was characterized by x-ray diffraction pattern and Raman spectroscopy. X-ray photoemission spectroscopy (XPS) was used to investigate the N 1s core level and nitrogen composition in TiO2-xNx thin films. The results indicated that the Ti-O-N bonds were formed in the thin films. Two nitrogen states, substitution and interstitial nitrogen atoms, are determined by the peak areas of 396.1 and 399.3 eV, respectively. It was observed that the nitrogen atoms exit the substitutional sites respective of nitrogen content in the thin films. UV-VIS absorbance spectroscopy of PET coated thin films appear a significant shift of the absorption edge to a lower energy in the visible-light region. The visible light irradiation has decided to active PET coated thin films for the development of super-hydrophilicity. The photo-induced surface wettability conversion reaction of the thin films was investigated by mean of water contact angle measurement. PET plates coated with TiO2-xNx thin films were found to exhibit a low water contact angle than without coated plates when the surfaces were illuminated with UV and visible light in the air. The relation between the effect and the amount of nitrogen doping on photo-generated hydrophilicity of the thin films, was investigated in this work.
CP-6 Vanadium Doping in Tungsten Oxide Thin Films Using a Single Target in Reactive DC Magnetron Sputtering Technique: Preliminary Results
K. Muthu Karuppasamy, A. Subrahmanyam (Indian Institute Of Technology Madras, India)
The oxide thin films of tungsten and vanadium have been studied for their interesting application in electro-chromic windows. The vanadium doping into tungsten lattice is anticipated to bring about interesting changes in the physical properties of tungsten oxide thin films. In the present study, we report the results of vanadium doped tungsten oxide thin films prepared at room temperature (300 K) by DC reactive Magnetron sputtering technique using a 66.0 mm dia magnetron cathode designed and fabricated "in house". The target is pure tungsten metal plate of thickness 1.0 mm. The vanadium doping is achieved by masking a calculated area in the erosion profile of the tungsten target with pure vanadium metal foil (the sputter yields of vanadium and tungsten are 0.7 and 0.6 for 600 eV argon ions); this technique of doping is new. Since the films prepared at 300 K are amorphous, they are annealed at 720 K for 10 hours to obtain the polycrystalline nature. The vanadium doping is ascertained by X ray diffraction and Energy Dispersive X ray Analysis (EDAX). The surface morphology of the films have been evaluated by scanning electron microscopy. The electro-chromic performance of the films is measured by cyclic voltammetry and time dependent transmittance measurements during coloring and bleaching cycles. It is observed that the bleached state transmittance for the vanadium doped tungsten oxide thin films depends upon the vanadium content in the film. The main advantage anticipated with vanadium doping is that the enhanced durability, transparency and color neutrality.
CP-7 Indium Tin Oxide Films Prepared via Wet Chemical Route
M. Cremona (PUC-Rio, Brazil); S.A.M. Lima, M.R. Davolos, H.H.S. Oliveira (Instituto de Quimica - UNESP, Brazil); C. Legnani, W.G. Quirino, R. Machado (Inmetro, Brazil); R.M.B. dos Santos (PUC-Rio, Brazil); C.A. Achete (Inmetro - Dimat, Brazil)
Indium tin oxide (ITO) is a very attractive material for optoelectronic applications due to its useful properties such as high transmittance in the visible region of the spectrum and high conductivity. The combination of its electrical and optical properties enables its use as transparent conductive oxides (TCO) in several optoelectronic devices, for example in OLEDs and solar cells. Normally, these kind of films are produced by deposition under vacuum and with specific thermal conditions. In this work, ITO films were prepared via chemical wet route. An aqueous solution of indium nitrate was mixed with an aqueous solution of tin nitrate. The molar ratio - [In3+] / [Sn4+] = 9 - has been fixed to assure the doping percentage in 10 at%, which was confirmed by X-ray photoelectron spectroscopy of the film. This solution was heated at about 60°C. Under stirring, it was added citric acid and etileneglicol. This solution was then used to be span over a vitreous substrate by spin-coating technique. The film was finally fired in an open oven at 500°C for 30 min. The ITO films were optically, structurally and electrically characterized by atomic force microscope (AFM), Hall system, UV-Vis, scanning electron microscopy (SEM), ultraviolet photoelectron spectroscopy (UPS) and Auger spectroscopy. The optical transmittance of the films is about 85% at 550 nm, with a grain size of 30 nm and a roughness of 0.63 nm RMS. The resistivity, mobility and carrier concentration were 3.5x10-3 Ωcm, 5.6 cm2/V-s and -3.63x1015 cm-3, respectively. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction, the films appear to be crystalline with a [222] orientation.
CP-8 Water Permeation Study of Plasma Polymerized TMDSO for Organic Light Emitting Diode Application
Y.X. Liu, X.C. Chang, Y.S. Lee, J.L. He, C.-K. Lin (Feng Chia University, Taiwan)
In this study, TMDSO (C4H14OSi2) was used as a precursor to produce plasma polymerized coatings on the polycarbonate (PC) polymer and OLED device for evaluation of its possibility as a water-barrier layer. Process parameters including precursor concentration and film thickness were changed to reveal their effect on film microstructure and water vapor transmission rate (WVTR). Durability of the coated OLED devices under humid environment was also evaluated. Experimental results show that the deposited films consist of Si-C, Si-O, Si-CH3, Si-OH and saturated C-H functional groups with pin-hole free amorphous feature. When the precursor concentration is decreased, film deposition rate is decreased and presents an inorganic glassy structure. This benefits a low WVTR value of the deposited film, though all the deposited substrates (10.6-14.6 g/m2/day) present a lower value than bare PC substrate (53.4 g/m2/day) and relatively irrelevant to the film thickness. The film with thickness of 5 µm deposited at the lowest precursor concentration in this study presents a WVTR value of 10.6 g/m2/day. This corresponds to the highest durability of the coated OLED device. Key words: plasma polymerization, TMSO, polycarbonate, organic light-emitting diodes, water vapor transmission rate.
CP-9 Microstructure and Physical Properties of Filtration Arc Ion Plated ITO Thin Film
M.S. Leu, J.-J. Chang, J.-B. Wu (Industrial Technology Research Institute, Taiwan); C.-H. Hsu (Tatung University, Taiwan)
The high quality indium tin oxide (ITO) thin films have been deposited at temperature of about 100°C successfully by using the cathodic vacuum arc deposition system and the sintered oxide target. Filter was incorporated to the system in order to get rid of oversized particles. The surface roughness of the ITO film could be decreased to less than 5 nm. The resistivities of ITO films were achieved to be about 3.04*10-4 Ω-cm and 4.09 *10-4 Ω-cm corresponding to the glass and PET substrates, respectively. The visible transparencies of ITO films were higher than 85% on both glass and PET substrates. The effects of bias voltage, arc current and oxygen partial pressure to thin film properties were also investigated. Our results show that this is a simple way to reduce the macroparticles and obtain high quality ITO films.
CP-10 Study of Ag Nanoparticles Incorporated SnO2 Transparent Conducting Films by Photochemical Metal-Organic Deposition
H. Kim, H.-H. Park, H.-H. Park (Yonsei University, Korea); H.J. Chang (Dankook University, Korea); R.H. Hill (Simon Fraser University, Canada)

Tin oxide (SnO2) has attracted much attention as a transparent conducting oxide of solar cell and more recently transparent thin film devices. For the application to the electrical devices, an improvement in electrical property of SnO2film has been absolutely required. Due to its high conductivity and chemical stability, Ag is widely used for the manufacture of conductive thick film circuits and for the internal electrodes of multilayer ceramic capacitors.

In this work, SnO2films were prepared by photochemical metal-organic deposition using photosensitive procedures. The films contain Ag nanoparticles prepared by spontaneous reduction method of Ag 2-ethylhexanoate in the solvent of dimethyl sulfoxide. X-ray diffraction was served to provide the information of the crystalline structure of hybridized SnO2films with Ag nanoparticles. Scanning electron microscopy was used to investigate the microstructure of the films. The optical transmission spectrum was obtained by using UV-VIS-NIR spectrophotometer. Light absorption and charge emission behaviors of the films were investigated. Even though the incorporation of Ag nanoparticles into SnO2films, the transparency of the film was not changed but the electrical sheet resistance was decreased.
CP-11 Effect of Plasma Post-Treatment on the Photoluminescence Characteristics of Al-doped ZnO Thin Films
H.-S. Yun, S.-H. Kim, S. Cho, N.-S. Kim, K.-D. Kim, S.S. Yi (Silla University, Korea)
We present the effects of plasma post-treatment on the optical properties of Al-doped ZnO (ZnO:Al) films grown on sapphire substrates by a radio-frequency (RF) magnetron sputtering system. ZnO:Al films are post-treated with hydrogen and/or oxygen plasma reactions using either RF or microwave plasma-enhanced chemical vapor deposition system. As for the hydrogen plasma-treated films, a significant increase in the band intensity of photoluminescence (PL) spectra at around 420 nm, corresponding to the blue-green emission region, is observed. While the oxygen plasma-treatment leads to a distinct appearance of the PL peak centered at around 610 nm. The crystal structure and the surface morphologies of the plasma-treated films are investigated by X-ray diffraction and atomic force microscopy and are compared with those of the as-grown films. Based on these results, the mechanism in the change of the photoluminescence characteristics for the plasma-treated samples is discussed using the Varshni equation.
CP-12 Optical Properties and Fabrication of Ga Doped ZnO Nanowires Grown on Si Substrate by TCVD
L.-W. Chang, M.-W. Huang, F.S. Shieu (National Chung-Hsing University, Taiwan)
Ga doped zinc oxide (ZnO) single-crystalline nanowires with a wurtzite hexagonal structure have been prepared by thermal chemical vapor deposition(TCVD) through a two-step evaporation process to enhance the optical properties and are distributed on a p-type Si (100) substrate. The growth of the ZnO nanowires was made by using metallic Zn powers (purity:99.99%) being heated up to 700°C at the rate of 15°C/min using a mixture of Ar and O2 gases at the first stage. To connect the above step, via HNO3 etching ZnO nanowires of surface to form the defects, and then doping Ga on the place of the defects by reheating samples with a flow of NH3 and Ar at 850°C. A model for self-catalyzed growth of Ga doped ZnO nanowires of diameters 40-100nm and length up to several tens of micrometers is established. The as-synthesized Ga-doped ZnO nanowires were characterized by high-resolution transmission electron microscopy, field emission scanning electron microscopy,x-ray diffraction and Raman scattering. The optical properties of the products were studieded by photoluminescence and cathodoluminescence spectra which exhibit green emissions possibly induced from singly ionized oxygen-vacancy density, and transmits to a light on potential applications in nanoelectronic devices.
CP-14 Optical and Structural Characterization of ZnO-In Thin Films
C.-Y. Chen, J.-L. Huang (National Cheng-Kung University, Taiwan); D.-F. Lii (Cheng Shiu University, Taiwan); D.R. Sahu (National Cheng-Kung University, Taiwan)
The ZnO-In films has been successively deposited by magnetron co-sputtering method using ZnO/In targets. The influence r.f. power on the microstructure, phase composition and electrical conductivity has been intensively investigated. The results show that In oxide is a major component, but Zn content greatly affects the thin films properties, such as optical property. The high transmittance of 93% was observed for films with 25 at% of indium. The PL-curves of ZnO:In films deposited at various r.f. powers show that the shift of characteristic peaks match the In content changes. PL curves peaks of ZnO-In films appear at different location from pure ZnO 380nm, due to the interaction of In2O3 and ZnO. The crystalinity (calculated from the FHWM values) influences obviously the transmittances. Highly transparent films can be deposited by controlling the parameter of rf power. No difference has been observed for the crystallite size of the film in this study.
CP-15 Transparent Conducting GZO, Pt/GZO, and GZO/Pt/GZO Thin Films
J. Ting, J. Cheng (National Cheng Kung University, Taiwan)
Transparent conducting thin films of GZO, Pt/GZO, and GZO/Pt/GZO were prepared and characterized for their microstructure, electrical conductivity, and optical properties. The films were deposited on glass substrates using a magnetron sputter deposition method. GZO, Pt/GZO, and GZO/Pt/GZO thin films obtained exhibit different total thicknesses and/or layer thicknesses. While the GZO thin films exhibit optical transmittances greater than 80% in the visible range, the electrical resistivity is high, in the order of 10-2 --cm. To reduce the electrical resistivity, a Pt layer is introduced to form either bi-layer Pt/GZO films or tri-layer GZO/Pt/GZO films. The electrical resistivity is therefore significantly reduced to as low as ~10-4 --cm. The optical transmittances of Pt/GZO films and GZO/Pt/GZO films were found to depend on the film characteristics, including thickness. Theoretical calculations were performed to discuss the effects of the thickness on the optical transmittance. The calculated data are in a good agreement with the experimental data provided. The theoretical calculations also allow the prediction of layer thickness such that improved optical transmittance can be achieved in GZO/Pt/GZO films.
CP-16 The Properties of ZnO/Cu/ZnO Multilayer Films Before and After Annealing in the Different Atmosphere
D.R. Sahu, J.-L. Huang (National Cheng-Kung University, Taiwan)
ZnO/Cu/ZnO multilayer films were prepared on glass substrates by simultaneous RF magnetron sputtering of ZnO and dc magnetron sputtering of Cu. The influence of post growth annealing on the structural, electrical and optical properties of the multilayer are investigated. The experimental results show that the properties of the film are improved with post annealing in vacuum and nitrogen and deteoriated in air and oxygen atmosphere. X-ray diffraction measurement indicated the multilayer films are c-axis oriented similar to ZnO wurzite structure. The samples heat treated up to 200°C under vacuum or nitrogen atmosphere showed transmittance over 85% at 580 nm wavelength and sheet resistance of about 10 -/Sq. The better electrical and optical properties of the multilayer will be achieved with proper optimization of growth condition of the copper layer and the use of appropriate annealing temperature and atmosphere.
CP-17 Application of Mesoporous SiO2 as Thermal Isolation Layer for Infrared Sensor
S.G. Choi, T.-J. Ha (Yonsei University, Korea); B.-G. Yu (Electronics and Telecommunications Research Institute, Korea); H.-H. Park (Yonsei University, Korea)
IR sensors have a wide range of applications from military to commercial product. Uncooled thermal infrared imaging sensor is a resistive sensor that detects temperature changes through resistance change. Thermal properties of materials for IR sensor are very important and these are main characteristics to determine sensor,s efficiency. Uncooled thermal imaging sensor has a vacuum cavity that helps λ /4 resonant infrared absorption. To improve detecting ability, sensor should be thermally isolated from the substrate and detecting materials. Formation of a vacuum cavity is accomplished by etching sacrificial layer process but that is complicate procedure. So, if a cavity is replaced other materials which has a thermal isolation property like vacuum, more simple manufacturing process is possible to make a infrared imaging sensor structure. In this study, low thermally conductive mesoporous silica film was adopted as a thermal insulation layer to replace vacuum cavity in infrared sensor structure. An effective thermal isolation and simple manufacture process will be possible by application of mesoporous silica film. To research the effects of filled cavity structure by mesoporous material provides a better way of improving sensor efficiency and simple manufacture process. An amorphous Si was used as a resistor and Si wafer was used as substrate. A decrease in thermal conductivity of infrared sensor system due to high thermal insulating gap filled layer induces the enhanced total abilities of infrared sensor.
CP-18 Structural and Optical Properties of V2O5 Nano Powder and Thin Films
A. Kumar, P. Singh (IIT Roorkee, India); D. Kaur (IITR, Roorkee, India)
We report the structural and optical properties of thin films of vanadium oxide prepared via evaporation technique on glass substrates. Structure and morphology of V2O5 thin films were investigated by using XRD, FESEM, AFM, HRTEM and XPS. V2O5 nanopowder was also prepared at low temperature. The nanopowder was characterized by insitu high temperature XRD and HRTEM. The studies revealed that the crystallite size varies systematically with insitu annealing. The deposition temperature was also found to have a great impact on the optical and structural properties of the V2O5 thin films. FESEM and AFM studies of the films deposited at room temperature showed homogeneous, uniform and smooth texture. XRD pattern of these room temperature deposited films revealed amorphous nature and these films remain amorphous even after post annealing at 300°C. Further investigation revealed that nanocrystalline V2O5 films with preferred 001 orientation could be grown with a layered structure onto glass substrates at temperature ≥ 200°C and V2O5 phase was found to remain stable till deposition temperature of 500°C. XPS studies revealed that the film deposited at room temperature shows the splitting of the V 2p level in accordance with the spins and the values of binding energies corresponding to V 2p and O 1s of these film are comparable with the film deposited at 300°C. XPS study confirmed that the room temperature deposited film were stoichiometric. Optical studies revealed the systematic variation of transmittance and energy band gap with crystallite size as calculated from XRD pattern. These room temperature deposited amorphous V2O5 film are the potential candidates for cathode material in thin film Lithium ion batteries.
Time Period ThP Sessions | Topic C Sessions | Time Periods | Topics | ICMCTF2007 Schedule