Correlations between the Optical Properties and the Microstructure of TiO2 Thin Films Prepared by Reactive Electron-beam Evaporation

High refractive index TiO₂ thin films were deposited on BK7 glass by reactive electron—beam (REB) evaporation at pressure of 2×10⁻² Pa, deposition rate of 0.2 nm/s and at various substrate temperatures from 120°C to 300°C. The refractive index and the thickness of the films were measured by visible spectroscopic ellipsometry (SE) and determined from transmission spectra. Optical properties and structure features were characterized by UV-VIS, SEM and XRD, respectively. The measurement and analysis on transmission spectra of all samples show that with the substrate temperature increasing from 120°C to 300°C, the refractive indices of thin films increase from 1.7 to 2.1 and the films after heat treatment have higher refractive indices due to its crystallizing. The XRD analysis results indicate that the structure of TiO₂ thin films deposited on BK7 glass at substrate temperatures of 120°C, 200°C and 300°C is amorphous, after post-annealing under air condition at 400°C for 1 hour, the amorphous structure is crystallized, the crystal phase is of 100% anatase with strong preferred orientation (004) and the grain size of crystalline is within 3.6–8.1 nm, which is consistent with results from SEM observation. WANG Xue-hua: Born in 1976. Funded by the Youth Project Foundation of Hubei Provincial Education Department (No. 2003B00)     

Preparation of ITO nano-powders by hydrothermal-calcining process

1 INTRODUCTIONSn-doped In2O3(ITO) is one kind of n-typesemiconductor material[1].It has excellent electro-optical properties , such as electrical conductivityand high transparency under visible light[2],andiswidely used in electronic , transparent electrode ,solar cells and electro-irradiance , especially inscreen display[3 ,4].Recently nearly half of the met-al indium has been used to prepare ITO materialsin the developed countries[5], such as Japan, A-merica ,France and so on.So the…     

Influence of crystal structure on friction coefficient of ZnO films prepared by atomic layer deposition

In this work, the influence of crystal structure on the friction coefficient of zinc oxide(ZnO) films was studied. The ZnO films were deposited on a Si(100) substrate using an atomic layer deposition process, and the crystal structure of the ZnO films was changed by adjusting the substrate temperature. The surface morphology and the crystal structure of the Zn O films were measured by an atomic force microscope and an X-ray diffractometer, respectively, and the friction coefficient of the ZnO films was measured by a ball-on-disk dry sliding tester. The results show that the ZnO films deposited at substrate temperatures below 200°C are dominated by(100),(002) and(101)-orientated crystals, while the ZnO films deposited at substrate temperatures above 250°C are dominated by(002)-orientated crystals, and that the crystal structure influences the friction coefficient of ZnO films greatly. The ZnO films with(002)-orientated crystals possess a larger friction coefficient than those with other orientated crystals. In order to verify this conclusion, we measured the friction behavior of the ZnO single crystals with different orientations. The results are consistent well with our conclusion.     

Fabrication of Poly-Si Thin Film on Glass Substrate by Aluminum-induced Crystallization

Amorphous silicon （ a-Si ） thin films were deposited on glass substrate by PECVD, and polycrystalline silicon （ poly- Si ） thin films were prepared by aluminum- induced crystallization （ AlC ）. The effects of annealing temperature on the microstructure and morphology were investigated. The AlC poly-Si thin films were characterized by XRD, Raman and SEM. It is found that a-Si thin film has a amorphous structure after annealing at 400℃ for 20 min, a-Si films begin to crystallize after annealing at 450 ℃ for 20 min, and the crystallinity of a-Si thin films is enhanced obviously with the increment of annealing termperature.     

Effect of silver growth temperature on the contacts between Ag and ZnO thin films

Highly c-axis oriented ZnO thin films were deposited on Si substrates by the pulsed laser deposition (PLD) method. At different growth temperatures, 200 nm silver films as the contact metal were deposited on the ZnO thin films. The growth temperatures have great influence on the crystal quality of Ag films. Current-voltage characteristics were measured at room temperature. The Schottky contacts between Ag and ZnO thin films were successfully obtained when silver electrodes were deposited at 150°C and 200°C. Ohmic contacts were formed while the growth temperatures were lower than 150°C or higher than 200°C. After analysis, the forming of Ag/ZnO Schottky contacts was shown to be dependent on the appearance of the p-type inversion layer at the interface between Ag and ZnO layers.     

Effects of Substrate Temperatures on the Structure and UV-shielding Properties of TiO2-CeO2 Films Deposited on Glass by Radio-frequency Magnetron Sputtering

TiO2-CeO2 films were deposited on soda-lime glass substrates at varied substrate temperatures by rf magnetron sputtering using 40% molar TiO2-60% molar CeO2 ceramic target in Ar：O2=95：5 atmosphere.The structure,surface composition,UV-visible spectra of the films were measured by scanning electron microscopy and X-ray diffraction,and X-ray photoelectron spectroscopy,respectively.The experimental results show that the films are amorphous,there are only Ti^4＋ and Ce^4＋ on the surface of the films,the obtained TiO2-CeO2 films shou a good uniformity and high densification,and the films deposited on the glass can shield ultraviolet light without significant absorpition of visible light,the films deposited on substrates at room temperature and 220℃ absorb UV effectively.     

Synthesis of 3D ordered macroporous indium tin oxide using polymer colloidal crystal template

Three-dimensional (3D) ordered macroporous indium tin oxide (ITO) is pre- pared using a polymer colloidal crystal template that is formed by self-assembly of the monodisperse poly(methyl methacrylate) (PMMA) microspheres. The morphologies and BET surface area of the macroporous material is examined by scanning electron micro- scope, transmission electron microscopy and N2 adsorption/desorption. Results indicate that the macroporous material has highly ordered arrays of the uniform pores replicated from the PMMA colloidal crystal template when the polymer colloidal crystal template is removed by calcinations at 500℃. The pore diameter (about 450 nm) of macroporous ITO slightly shrank to the PMMA microspheres. The BET surface area and pore volume of the macroporous material are 389 m2·g-1 and 0.36 cm3·g-1, respectively. Moreover, the macroporous ITO, containing 5 mol% Sn and after annealing under vacuum, shows the minimum resistivity of ρ = 8.2×10-3 Ω· cm. The conductive mechanism of macroporous ITO is discussed, and it is believed that the oxygen vacancies are the major factor for excellent electrical properties.     

Preparation of Indium Tin Oxide Films on Polycarbonate substrates by Radio-frequency Magnetron Sputtering

1Introduction Indiumtinoxide(ITO)isadegeneraten typesemi conductingmaterialthathaswideapplicationsinoptics andoptoelectronics,suchasflatpaneldisplaydevices,antireflectioncoatings,pilotwindows,andheterojunction solarcells.Itselectricalopticalpropertieshave…     

磁控溅射法制备的不同衬底上的TiO_2薄膜

利用射频磁控溅射方法,分别在改变氧气含量和沉积时间的条件下在ITO玻璃、Si和Al/ITO玻璃衬底上沉积了TiO2薄膜,并利用拉曼光谱表征了2种条件下的TiO2薄膜的结构.研究表明：衬底材料、氧气含量以及沉积时间明显地影响了TiO2薄膜的结构.随着氧气含量的降低,沉积在ITO玻璃衬底上的TiO2薄膜由锐钛矿和金红石的混合结构转变为单一的金红石结构,而沉积在Si衬底上的TiO2薄膜的结构没有改变,并保持单一的金红石结构;随着沉积时间的增加,Al/ITO玻璃衬底上的TiO2薄膜由金红石结构转变为锐钛矿结构.     

Structure and properties of TiB<Subscript>2</Subscript> thin films deposited at low temperatures using RF magnetron sputtering

The TiB2 thin films were deposited on steel substrates using RF magnetron sputtering technique with the low normalized substrate temperature （0.1〈Ts/Tm〈0.2）. Microstructure of these films was obtained by field emission scanning electron microscope （FESEM） and the grazing incidence X-ray diffraction （GIXRD） characterization, while the composition of films was obtained using Auger emission spectroscopy （AES） analysis. It was found that the TiB2 thin films were overstoichiometric with the B/Ti ratio at 2.33 and the diffusion of Ti and B atoms on the substrate surface was greatly improved at 350 ℃. Moreover, a new dense structure, named ＂equiaxed＂ grain structure was observed by FESEM at this substrate temperature, Combined with FESEM and AES analysis, it was suggested that the ＂equiaxed＂ grain structure was located in Zone 2 at the normalized substrate temperature as low as 0.18.     

Effect of Annealing on Structural, Optical and Electrical Properties of CdS Thin Films Grown by ILGAR

CdS thin films were deposited by ILGAR （ ion lay gas reaction） method. The effect of annealing temperature under N2 atmosphere on the structural, chemical, topographical development and optical and electrical properties of CdS thin films was investigated by XRD, SEM, XPS, UV- VIS and two-probe technique. It is found that the cubic-phase of as-deposited CdS film transforms to hexagonal phase with a perfected orientation along （002） plane at 300 ℃ . The band gap decreases with increasing annealing temperature until 300 ℃ , which is consistent with the grain growth. The fall of dark and light resistivitiy is obvious with increasing annealing temperature, corresponding to the continuous grain growth and deviation of stoichiometry at higher temperature. The smooth and uniform surface of as-deposited films becomes rougher through thermal treatment, which is related to grain growth and sublimation of CdS at a higher annealing temperature.     

Effect of the sputtering parameters on the structure and properties of Cu<Subscript>3</Subscript>N thin film materials

Copper nitride (Cu₃N) thin films were successfully deposited on glass substrates by reactive radio frequency magnetron sputtering. The effects of sputtering parameters on the structure and properties of the films were studied. The experimental results show that with increasing of RF power and nitrogen partial pressure, the preferential crystalline orientation of Cu₃N film is changed from (111) to (100). With increasing of substrate temperature from 70 °C to 200 °C, the film phase is changed from Cu₃N phase to Cu. With increasing sputtering power from 80 W to 120 W, the optical energy decreases from 1.85 eV to 1.41 eV while the electrical resistivity increases from 1.45 ×10² Ω · cm to 2.99 × 10³ Ω · cm, respectively.     

低阻ITO玻璃的制造工艺

有机发光显示器件是目前平板显示中的热点,所用ITO玻璃比液晶显示所用的有更高更严的要求。该文探讨了OLED用ITO玻璃生产的相关工艺,得出使用直流溅射ITO陶瓷靶时,较好的气氛是低氩微氧,功率约200 W左右,溅射时基板温度约250℃,高温无氧退火。得到方阻20Ω以下、平均透过率大于80%的ITO玻璃。     

半导体器件钝化层Si3N4薄膜的制备及特性研究

采用热分解法在硅衬底上制备了Si3N4薄膜，根据在制备过程中薄膜生长速度随颜色的变化，研究了衬底温度和薄膜沉积速率之间的关系，分别利用AFM对薄膜表面进行观测，C—V法对薄膜和硅片界面态进行了测试。结果表明：所制备的Si3N4薄膜在硅片上以无定形方式存在，在Si3N4薄膜和硅界面之间存在着大量的表面电荷，由于这种高密度表面电荷的存在，导致Si3N4薄膜不适于直接作为半导体器件的表面钝化层。     

Structure and Composition of Crystalline Carbon Nitride Films Synthesized by Microwave Plasma Chemical Vapor Deposition

Crystalline carbon nitride thin films were prepared on Si (100) substrates by a microwave plasma chemical vapor deposition method, using CH4/N2 as precursor gases. The surface morphologies of the carbon nitride films deposited on Si substrate at 830℃ are consisted of hexagonal crystalline rods. The effect of substrate temperature on the formation of carbon nitrides was investigated. X-ray photoelectron spectroscopy analysis indicated that the maximum value of N/C in atomic ratio in the films deposited at a substrate temperature of 830℃ is 1 .20, which is close to the stoichiometric value of C3N4. The X-ray diffraction pattern of the films deposited at 830℃ indicates no amorphous phase in the films, which are composed of β- and α-C3N4 phase containing an unidentified C-N phase. Fourier transform infrared spectroscopy supports the existence of C-N covalent bond.     

Structure and Composition of Crystalline Carbon Nitride Films Synthesized by Microwave Plasma Chemical Vapor Deposition

Crystalline carbon nitride thin films were prepared on Si (100) substrates by a microwave plasma chemical vapor deposition method, using CH4/N2 as precursor gases. The surface morphologies of the carbon nitride films deposited on Si substrate at 830℃ are consisted of hexagonal crystalline rods. The effect of substrate temperature on the formation of carbon nitrides was investigated. X-ray photoelectron spectroscopy analysis indicated that the maximum value of N/C in atomic ratio in the films deposited at a substrate temperature of 830℃ is 1.20, which is close to the stoichiometric value of C3N4. The X-ray diffraction pattern of the films deposited at 830℃ indicates no amorphous phase in the films, which are composed of - and -C3N4 phase containing an unidentified C-N phase. Fourier transform infrared spectroscopy supports the existence of C-N covalent bond.     

Extraordinary self-lubrication properties of non-hydrogenated diamond-like carbon films under humid atmosphere

Tribological properties of non-hydrogenated diamond-like carbon (DLC) films were investigated under humid (RH=80%) and dry (RH=5%) air. These films were deposited by pulsed laser deposition (PLD) at different substrate temperatures. Tribological properties of DLC fabricated by PLD is not sensitive to the relative humidity of testing environment. Because of the unique growth mechanism of DLC prepared by PLD, DLC is of “soft-hard” double layers, having a very low friction coefficient and wear rate under humid atmosphere. The minimum coefficient and wear rate of film under humid circumstance are 0.045 and 5.94×10⁻¹⁰ mm³N⁻¹m⁻¹, respectively, just a little bit more than those under dry condition. The root means square roughness of film is less than 1 nm. The sp³ content of film grown at room temperature (RT) is 72%, and the sp³ content decreases with temperature. Raman spectrum shows that the micro-structure is amorphous network. The largest hardness and elastic modulus of film are 51 GPa and 350 GPa, respectively and they reduce with increase of deposition temperature too. Water contact angles on surface are more than 90° which indicates that films fabricated by PLD are hydrophobic with low surface energy.     

Superplastic behavior of reciprocating extruded Mg-6Zn-1Y-0.6Ce-0.6Zr from rapidly solidified ribbons

RRE-Mg66 alloy with a composition of Mg-6.0%Zn-1.0%Y-0.6%Ce-0.6Zr was prepared by combinatorial processes of rapid solidification, reciprocating extrusion and extrusion. Microstructure was evaluated on SEM and TEM. The average grain size of the alloy is 0.7 ??m, the size of the second phase at grain boundary is 0.15 ??m, and the size of the intragranular precipitates in round shape is less than 20 nm. Superplastic behavior of the material was investigated in a temperature range of 150 to 250 °C and initial strain rate range of 3.3×10^?4 to 3.3×10^?2 s^?1 in air. The highest elongation of 270% was obtained at 250 °C and 3.3× 10^?3 s^?1. High-strain-rate superplasticity and low-temperature superplasticity were achieved. The superplasticity results from intragranular sliding (IGS) at temperatures from 170 to < 200 °C and grain boundaries sliding (GBS) at 250 °C. At 200 °C a combination of IGS and GBS contributes to the superplastic flow.     

Flux pinning effect of cubic equiaxed morphology and its Ti stabilizing in Nb<Subscript>3</Subscript>Sn superconductors

Two sets of internal-Sn Nb3Sn superconducting strands were fabricated through RRP method, one with 2 wt% of Ti alloyed in Sn core and the other just pure Sn. Four reaction temperatures of 650℃, 675℃, 700℃ and 725℃ and 128 h duration were applied for A15 phase formation heat treatment after Cu-Sn alloying procedure of 210℃/50 h + 340℃/25 h. For the heat-treated coil samples, transport non-Cu JC was examined through standard 4-probe technique and phase microstructure was observed by means of Field Emission Sc...     

Preparation and Properties of CdTe Polycrystalline Films for Solar Cells

The structure and characteristics of CdTe thin filrns are closely dependent on the whole deposition process in close-space sublimation （CSS）. The physical mechanism of CSS was analyzed aud the temperature distribution in CSS system was measured, and the influences of the increasing-temperature process and pressure on the preliminary nucleus creation were studied. The resuits indicate ： tire samples deposited at different pressures hare a cubical structure of CdTe and the diffraction peaks of CdS and SnO2 ： F. As the atmosphere pressure increases, the crystal size of CdTe decreases, the rate of the transparency of the thin film decreases and the absorption side moves towards the short-wave direction. After a 4-minute depositing process with a substrate teraw.rature of 500℃ and a source temperature of 620 ℃, the polycostallinc thin films can be mmade , so the production of high-quality integrated cell with StrO2： F/ CdS/ CdTe/ Au structure is hopeful.