Characterization of pyrolytically deposited V2O3 thin films

V₂O₃ films were deposited using the pyrolysis technique. The surface composition and structure of the deposited V₂O₃ films were investigated using scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and reflection high energy electron diffraction (RHEED). Electronic conductivity measurements of the films were also carried out as a function of temperature from room temperature to about 430 K.The SEM analysis showed a smooth film surface which on exposure at high intensity showed some form of restructuring. The AES, however, indicated the presence of carbon in the deposited film while the RHEED showed a streaked pattern which could result from the restructing observed in the SEM analysis.The electrical conductivity measurements showed metallic-type behaviour in the region investigated. A smooth second-order transition was observed at about 400 K.     

Characteristics of nanocomposite ZrO2/Al2O3 films deposited by plasma-enhanced atomic layer deposition

Nanocomposite ZrO2/Al2O3 (ZAO) films were deposited on Si by plasma-enhanced atomic layer deposition and the film characteristics including interfacial oxide formation, dielectric constant (k), and electrical breakdown strength were investigated without post-annealing process. In both the mixed and nano-laminated ZAO films, the thickness of the interfacial oxide layer (T(IL)) was considerably reduced compared to ZrO2 and Al2O3 films. The T(IL) was 0.8 nm in nano-composite films prepared at a mixing ratio (ZrO2:Al2O3) of 1:1. The breakdown strength and the leakage current level were greatly improved by adding Al2O3 as little as 7.9% compared to that of ZrO2 and were enhanced more with increasing content of Al2O3. The k of ZrO2 and mixed ZAO (Al2O3 7.9%) films were 20.0 and 16.5, respectively. These results indicate that the addition of Al2O3 to ZrO2 greatly improves the electrical properties with less cost of k compared to the addition of SiO2.     

Electron structure of thin fullerene films deposited by various methods

The valence-band photoelectron spectra and the photoelectron energy loss spectra behind the C1s peak in the X-ray photoelectron spectra were studied in thin fullerene films deposited by various methods. The fine structure in the density of states near the valence band bottom observed for the fullerene films deposited by the method of pulsed supersonic molecular beam (SMB) with a helium carrier may be indicative of the presence of a long-range order. The spectra of π-plasmon losses in the films obtained by methods of thermal and SMB deposition exhibit a significant difference that can be related to a closer packing of C₆₀ molecules in the latter case.     

两片大面积玻璃同时反应溅射沉积Al2O3均匀性试验

本工作设计制作了一种新型的三段式反应气体进气系统.该进气系统由镀膜真空室内和室外两部分结构组成.真空室内的进气主管由三段进气分管组成,其上装有等间距的进气喷嘴.真空室外装有与各进气分管对应的流量调节针阀.调试反应溅射Al2O3均匀性的方法如下.首先粗调流量调节针阀,改变各进气分管间的反应气体进气流量分布,然后更换不同横截面积的进气喷嘴,进一步调节反应气体进气流量沿靶长度方向分布.交替重复以上调试过程2～3次,即可获得沿靶长度方向上反应溅射沉积均匀、透明的A12O3薄膜.本工作在高1650 mm,宽2440 mm的靶前后两块大面积玻璃上,试验沉积了Al2O3/Ag/Al2O3低辐射薄膜.结果表明沉积的低辐射膜在靶前后两块大面积玻璃上均匀性好,可见光吸收比相对标准偏差小于4％.     

Photocatalytic TiO2 films deposited by different methods

Photocatalytic TiO₂ layers are deposited with different methods available within the Fraunhofer Photocatalysis Alliance. These are: Magnetron sputtering, evaporation, sol‐gel, laquer coating, and CVD. The photocatalytic activity under UV illumination is determined by decomposition of stearic acid. The optical properties of the films are compared and discussed.     

采用真空磁控反应溅射和沸水氧化法制备Al2O3增透膜

在玻璃基片上采用金属Al靶在溅射气体Ar和反应气体O2的混合气体中,真空磁控溅射半透明的Al-Al2O3金属陶瓷薄膜,再将沉积薄膜的玻璃基片浸入沸腾的去离子水中氧化,制备成陶瓷增透膜.优化镀膜工艺和沸水氧化时间,在3.2 mm厚的低铁玻璃载片上单面沉积的增透膜的太阳透射比Te由未镀膜原片的90.4％增加到93.9％,提高了3.5％,可见光透射比Tv由91.6％增加到95.5％,提高了3.9％.双面沉积增透膜玻璃载片的Te达到96.2％,增加了5.8％,Tv达到97.2％,增加了5.6％.经过400℃高温持续40 min烘烤后膜层的光学性能基本不变.     

Al/Al2O3多层膜的研究

用真空蒸镀及自然氧化方法在玻璃基底上制备纳米量级的4、5、6、7对层的Al／Al2O3多层膜。采用称重法测定薄膜的厚度；在常温和低温下使用三点法测定多层膜的电特性；用扫描电镜（sEM）观察薄膜的表面和截面的形貌及成分。结果表明：制备的是纳米量级非晶态的Al／Al2O3多层膜，在常温和低温（77K）下均具有类似负阻的特性。     

射频磁控溅射法制备Bi2O3薄膜的电致变色性能研究

采用射频磁控溅射技术在ITO导电玻璃上沉积了Bi_2O_3薄膜,利用X射线衍射仪、原子力显微镜、X射线光电子谱对薄膜的微结构、表面形貌、成分和价态进行了表征。分析表明在空气气氛中350℃热处理的Bi_2O_3薄膜具有四方结构,属β-Bi_2O_3,该薄膜在-1.8-+3V的直流电压驱动下具有在透明和暗棕色之间转换的电致变色性能,着色和漂白过程中均没有其他价态(+3价以外)的Bi生成。研究发现Bi_2O_3薄膜在400-800nm的可见光波段平均透射率调制幅度可达44%,550nm处着色系数为9.6cm~2/C,该材料具有优良的电致变色性能。     

Al2O3透明陶瓷显微结构的研究

采用高纯Al2O3(＞99.9%)粉末为原料,用无压烧结工艺制备Al2O3透明陶瓷.研究了添加剂Y2O3、烧结温度、保温时间等对Al2O3透明陶瓷显微结构和光学性能的影响.实验结果表明,适量的Y2O3能够抑制Al2O3晶粒的生长,改善烧结性能,但添加量过多会使Al2O3陶瓷气孔略有增加.在1800℃烧结的样品密度接近理论密度,具有较好的光学性能.延长保温时间能够使晶粒长大的同时有效排除晶界处少量气孔.     

Influence of Bi2O3 in the microstructure of SrBi2Ta2O3 films deposited by pulsed laser ablation

A systematic study of the microstructural features of SrBi₂Ta₂O₉ (SBT) films prepared on Pt(1 1 1)/TiO₂/SiO₂/Si by pulsed laser deposition (PLD) and heat treated at different temperatures, is presented. The films heat treated during deposition have a temperature-induced preferential growth in the (1 1 5) orientation and reach the SBT crystal structure at 600 °C, free from undesired secondary phases. From transmission electron microscopy and X-ray diffraction analysis, the morphology of the SBT and the Bi₂O₃ crystals in the films are determined. Additionally, the non-oriented polycrystalline growth and the development of cracks in films deposited at the lowest temperature (300 °C) and then annealed at high temperatures are explained. It is seen in these films that once the Bi₂O₃ crystal phase is eliminated during the post-annealing process, the growth of the SBT crystals is linear at a rate of of 0.8 nm ° C^-1. It is proposed, as a result of these studies, that a deposition temperature of at least 600 °C should be used to avoid the presence of crystalline Bi₂O₃ and cracking during the post-annealing treatment. © 2001 Kluwer Academic Publishers     

Characterization of (Al, Si)N films deposited by balanced magnetron sputtering

Hard and transparent nanocomposite (Al, Si)N films are attractive for optical applications. In this paper, experimental results will be reported on nanocomposite (Al, Si)N films prepared by balanced magnetron sputtering. Microstructure and properties of the films were systematically characterized as a function of Si content of the films. It is shown that the (Al, Si)N films are transparent and exhibit no absorption in a wide range of wavelengths from ~ 0.3 to ~ 9 µm, i.e. from ultraviolet to mid-infrared region. Maximum hardness exceeding 25 GPa has been obtained when the Si content of the films is above 25 at.% and the microstructure of the films undergoes a transformation from nanocrystalline to amorphous states. It is demonstrated that the microstructure detail of the films is different, as compared with that of the films prepared by using unbalanced magnetron sputtering, and the reasons for this discrepancy is discussed.     

Characterization of Al2O3 thin films fabricated through atomic layer deposition on polymeric substrates

This paper reports on the fabrication of good quality Al₂O₃ thin films on flexible substrates including polyethylene naphthalate (PEN), polyethylene terephthalate (PET) and Polyamide at different temperatures down to 50 °C under very short water purging steps of 10 s. Al₂O₃ films with appreciable growth rates having good morphological, chemical, electrical and optical characteristics have been produced. Growth rates of 1.16, 1.14 and 1.15 Å/cycle have been observed at 50 °C for PET, PEN and polyamide substrates respectively. The surface morphology has been improved with the increase in deposition temperature. Low average arithmetic roughness of 0.88 and 0.78 nm have been recorded for the Al₂O₃ films deposited at 150 °C on PEN and polyamide respectively. The XPS analysis confirmed the fabrication of Al₂O₃ films without any carbon contamination and Al 2p, Al 2s and O 1s peaks were appeared at binding energies of 74, 119 and 531 eV, respectively. Excellent insulating properties were observed for the Al₂O₃ films and optical transmittance of more than 85 % was recorded in the visible region. The experimental results suggest that polymeric materials are excellent candidates to be used as substrates in the fabrication of Al₂O₃ thin films through atomic layer deposition.     

掺Er-Al2O3薄膜发光特性的研究

通过离子束辅助沉积(IBAD)在热氧化SiO2上沉积Al2O3薄膜,在120keV下注入5×10115cm-2Er离子,Ar气氛下773～1273K退火1h.低温下测试PL谱线,随退火温度升高,发光强度上升.973K退火下发光强度特别低,并观察到Si衬底的1140nm峰.光透射谱表明几乎在所有的测试范围内尤其在1530nm处973K退火样品的透射谱强度最强,波导损耗最低.1530nm发光强度随退火温度的变化跟发光强度的变化相反.说明Er离子在514.5nm泵谱吸收界面σ跟Al2O3的光吸收损耗有一定关系.     

掺杂浓度对中频反应磁控溅射制备Al2O3:Ce3+薄膜发光性能的影响

应用中频反应磁控溅射设备在载玻片上制备掺铈的Al2O3薄膜,在固定的电源功率下,氩气流量为23sccm,氧流量为5sccm,室温下溅射时间为90分钟的条件下,通过控制薄膜中的Ce3+离子的掺杂量来改变薄膜的发光性能.通过X光能量散射谱(EDS)和光致发光测量,得到发光强度和发光峰位对薄膜中的Ce3+浓度有强烈的依赖关系,并且分析了产生这种关系的原因;对发光激发谱分析表明,薄膜发光是源于薄膜中形成的氯化铈集合体中的Ce3+.Al2O3:Ce3+发光膜可应用于需要蓝光发射的平板显示领域.     

Characterization of co-precipitated Al2O3−SiO2 gels

Aluminum nitrate and tetraethyl orthoxysilane were used as starting materials. They were mixed at different ratios ranging from 1.8 to 4.8 (Al³⁺/Si⁴⁺) and dissolved in ethyl alcohol. The pH of the reaction solution was also varied by the addition of ammonium hydroxide at a range of 8.3 to 10.4. Experiments were carried out at 25 and 60°C. In each case the materials were hydrolysed to a colloidal solution which was then filtrated and the resulting colloids retained on the filter as a gel which after drying at 110°C became a xerogel. The xerogels then were characterized by BET, SEM/TEM, and XRD/XRF. Of all the factors studied the pH of the reaction mixture was found to have the greatest affect on the morphology of the crystalline phase in the xerogels. Fibrous pseudoboehmite was found at the lower pH values of 8.3 and bayerite was present at pH value greater than 9.5 and became the predominant species at pH values greater than 10.4. The Al³⁺/Si⁴⁺ ratios and the reaction temperature both affected the crystallinity of the xerogels but to a much lesser degree than did the pH.     

Al2O3微粉的表面改性及表征

以α-Al₂O₃微粉为基体,Y(NO₃)₃水溶液为包裹相,采用液相包裹法进行加钇颗粒表面改性.获得了表面均匀包裹Y₂O₃的α-Al₂O₃粉体.将此粉体与Al合金复合制备复合材料.复合材料组织更加均匀.对材料进行力学性能测试,结果表明:改性粉体对Al合金增强效果明显增加,抗拉强度提高27.2％;屈服强度提高33.1％,延伸率提高10.3％.