室温溅射制备氧化锌铝薄膜及电性能研究

采用直流磁控溅射工艺,室温下在载玻片上制备了氧化锌铝透明导电薄膜.研究了溅射功率和氩气压强对薄膜微观结构和电性能的影响.研究表明:溅射功率和氩气压强通过改变晶粒尺寸和晶界所产生的散射作用而影响薄膜的导电性能.溅射功率低于100W时,薄膜的电阻率随功率增加而明显降低,但超过100W后,薄膜的电阻率下降趋缓,并最终趋于平稳;氩气压强在0.6～3.0Pa范围内增大时,薄膜的电阻率先缓慢减小后逐步增大,当氩气压强为1.5Pa时可获得1.4×103Ω·cm的最小电阻率.     

喷嘴速度系数的计算方法及影响因素

速度系数是衡量喷嘴内能量损失大小的一个指标。根据喷嘴速度系数的定义,指出其与能量损失系数和总压损失系数的关系,得出喷嘴速度系数的计算方法,喷嘴前后压比一定时,喷嘴速度系数随总压损失系数的增大而减小,并探寻影响喷嘴速度系数的影响因素。喷嘴速度系数除了与喷嘴的几何尺寸、流道形状有关外,还与喷嘴前后压比、叶片表面粗糙度、多变指数及马赫数有关。借助于Fluent商业软件,模拟喷嘴前后压比和表面粗糙度对喷嘴速度系数的影响,结果表明:当喷嘴前后压比一定时,喷嘴速度系数随表面粗糙度的增加而降低,且当表面粗糙度增加到一定程度时,喷嘴速度系数基本不变;且喷嘴速度系数受表面粗糙度的影响大于喷嘴前后压比。     

绒面ZnO:Al(ZAO)透明导电薄膜的制备

利用中频交流磁控溅射方法，采用氧化锌铝(98wt％ZnO 2wt％A12O3)陶瓷靶材制备了绒面ZAO(ZnO：Al)薄膜，考察了所制备的绒面ZAO薄膜与绒面SnO2：F薄膜在绒度、粗糙度、表面形貌以及电学性质的差异，利用原子力显徽镜对薄膜表面形貌进行了分析并计算出薄膜表面粗糙度，利用紫外可见分光光度计和电阻测试仪测量了薄膜的光学、电学特性。结果表明：所制备的绒面ZAO薄膜具有与绒面SnO2：F薄膜相比拟的各种性能，在非晶硅太阳电池中具有潜在的应用前景。     

TiO2涂层自洁净玻璃的制备及其特性研究

采用Ｓｏｌ－ｇｅｌ工艺在玻璃表面制得均匀透明的多孔ＴｉＯ２纳米薄膜，其纳米颗 在小在５０－１００ｎｍ范围。该玻璃透光性较好，在可见光范围内相对于范围内相对于普通４玻璃的透光率在６３％以上，同时可以阻挡紫外线的透过。两种有机磷农药水溶液的光催化降解实验表明：随着镀膜次数的增加，光催化效率提高，当镀膜次数达到５次以上时，其光解率提高就比较缓慢。     

NiOxHy薄膜电致变色性能的研究

利用直流磁控溅射法，在Ｏ２＋Ｈ２的气氛下制备了ＮｉＯｘＨｙ薄膜，研究了不同氢气含量对薄膜的初始沉积态、漂白态和着色态透光性能的影响，含氢量为８０％时，薄膜的初始沉积态的平均可见光透射比最高。含氢量为６０％时，薄膜的电致变色能力最佳。用获得的ＮｉＯｘＨｙ薄膜制备的反射型全固态电致变色器件的控光范围可达７７％。对ＮｉＯｘＨｙ薄膜三种状态的红外吸收光谱分析表明，ＮｉＯｘＨｙ薄膜的变色机理可用：Ｎｉ（ＯＨ）２（漂白态）＝ＮｉＯＯＨ（着色态）＋Ｈ＋＋ｅ－表示。     

晶相形成对TiSi2薄膜光学性能的影响

通过常压CVD方法由SiH4和TiCl4直接在玻璃基板上成功制备了TiSi2薄膜,用XRD、FESEM、四探针测阻仪和分光光度计研究了薄膜的结构、形貌、电学和光学性能。研究表明TiSi2薄膜的晶相是面心正交型TiSi2;薄膜的电阻率直接由晶相的形成决定,受晶相颗粒大小和晶相致密度控制,TiSi2薄膜的电阻率随薄膜中TiSi2晶相含量的增大而下降。TiSi2薄膜在400~750nm范围的可见光区具有大致相同的透射比和最小的反射比,薄膜的透射比随薄膜厚度的增加而减小。在大于750nm的红外区,薄膜电阻率越小,对红外辐射的反射比越高,且随着波长增加至25000nm,TiSi2薄膜的反射比逐渐上升到约0.95。     

RPD技术生长ICO∶H薄膜及其在晶体硅异质结太阳电池中的应用

通过反应等离子体沉积(RPD)技术室温下生长掺铈的氧化铟薄膜,且沉积过程中通入氢气。高迁移率可使透明导电薄膜在较低的电阻率时保持较高的近红外透过率;透明导电薄膜中较低的载流子浓度能够减少自由载流子的吸收。迁移率的大小主要由薄膜内的散射机制决定,并且受薄膜非晶结构制约。ICO∶H薄膜表面平整,在近红外长波段透过率超过80%。在氢气流量为2 sccm时,薄膜获得1.34×10^-3Ω·cm的最低电阻率和94 cm²/Vs的高迁移率。在晶体硅异质结(SHJ)太阳电池应用中,获得了较高的短路电流密度38.44 mA/cm²,相应的转换效率为16.68%。     

重型燃气轮机透平叶片表面粗糙度对换热的影响

以某重型燃气轮机透平第一级静叶的叶型为研究对象,采用商业软件CFX的等效砂粒粗糙度模型研究了表面粗糙度对叶片表面换热的影响。结果表明:表面粗糙度对叶片表面附近的时均流场影响不大;但在叶片典型表面粗糙度下,压力面和吸力面的换热水平分别比光滑表面时高36.6%和33.4%,换热发生恶化;较小的表面粗糙度对叶片前缘换热基本没有影响,但当等效砂粒粗糙度增大到51μm时,无量纲线平均传热系数反而比光滑表面时减小了15%;根据叶片一维传热过程模型,在换热增强30%时,叶片金属表面平均温度上升17 K,极大地影响了叶片的寿命。     

用MOCVD方法制备ZnO：B透明导电薄膜及其性能优化

采用金属氧化物化学气相沉积(MOCVD)方法在石英衬底上生长氧化锌(ZnO)薄膜.改变薄膜材料的生长温度和掺杂气体硼烷(B2H6)的流速,制备一系列薄膜样品.通过x-射线衍射(XRD)、扫描电子显微镜(SEM)、透过率、反射率、电阻率和原子力显微镜(AFM)等测试分析,研究了材料生长温度和B2H6流速对薄膜生长速度、微观结构、薄膜晶向、光学透过率、光学禁带宽度、电阻率、表面粗糙度等特征参量的影响,经过优化实验条件,获得薄膜电阻率在10-3Ω·cm量级,可见光区域光学透过率在85%以上,成功制备低电阻率高光学透过率的ZnO透明导电薄膜.     

具有镜面反射和漫反射的CPC光学分析

对由镜面反射为主但是存在一定漫反射的复合抛物面聚光器(CPC)反射面构成的集热器，在存在太阳散射情况下进行了光吸收性能的分析，比前人只考虑集热器镜面反射和太阳光直射更加接近实际情况。方法是在利用光线追踪法对CPC反射面的镜面反射进行分析的基础上，结合辐射度算法定量计算了CPC反射面的漫反射和太阳光的散射分量对集热器的光学性能的直接影响。并通过CPC集热器瞬时效率测试验证了理论的正确性。通过该理论，可以在更接近实际的情况下对CPC集热器进行光学设计和计算，具有实际的应用价值。     

Recent advances in electrochromics for smart windows applications

Electrochromic smart windows are able to vary their throughput of radiant energy by low-voltage electrical pulses. This function is caused by reversible shuttling of electrons and charge balancing ions between an electrochromic thin film and a transparent counter electrode. The ion transport takes place via a solid electrolyte. Charge transport is evoked by a voltage applied between transparent electrical conductors surrounding the electrochromic film/electrolyte/counter electrode stack. This review summarizes recent progress concerning: (i) calculated optical properties of crystalline WO₃, (ii) electrochromic properties of heavily disordered W oxide and oxyfluoride films produced by reactive magnetron bias sputtering, (iii) novel transparent reactively sputter-deposited Zr–Ce oxide counter electrodes and (iv) a new proton-conducting antimonic-acid-based polymer electrolyte. Special in depth presentations are given on elastic light scattering from W-oxide-based films and of electronic band structure effects affecting opto–chronopotentiometry data in Zr–Ce oxide. The review also contains some new device data for an electrochromic smart window capable of very high optical transmittance.     

玻璃衬底和硅衬底沉积TZO透明导电薄膜的对比研究

利用直流磁控溅射法在室温水冷玻璃衬底和硅片衬底上制备出掺钛氧化锌(ZnO∶Ti)透明导电薄膜。SEM和XRD研究结果表明,两种衬底上的ZnO∶Ti薄膜均为为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向。讨论了衬底对掺钛氧化锌透明导电薄膜光学、电学性能的影响。当玻璃衬底薄膜厚度为568nm时,薄膜电阻率达到最小值1.64×10-4Ω.cm,硅衬底上薄膜厚度为641nm时有最小电阻率2.69×10-4Ω.cm。两种衬底所制备薄膜都具有良好的附着性能,玻璃衬底薄膜样品在波长为500~800nm的可见光中平均透过率都超过了91%,硅衬底上薄膜样品的折射率约为2.05,ZnO∶Ti薄膜可以用作薄膜太阳电池的透明电极。     

High quality ZnO and Ga:ZnO thin films grown onto crystalline Si (1 0 0) by RF magnetron sputtering

Undoped and 2% Ga-doped ZnO films have been deposited by RF magnetron sputtering onto single crystal Si (1 0 0) substrates equivalent to the commercial Si solar cells. The same films were also grown on amorphous silica substrates to complete their characterization. The films have been characterized by X-ray diffraction, electrical and optical measurements, X-ray photoelectron spectroscopy, Raman microspectroscopy and scanning and high-resolution transmission electron microscopy. Films present a very good quality crystalline wurtzite structure with the c-axis perpendicular to the substrate, with continuity of the (0 0 0 2) planes along the whole film, as shown by transmission electron microscopy. The doped sample shows an increase of two orders of magnitude of the electrical conductivity, an optical transmittance bigger than 85% along the visible spectrum, a diminution of the grain size in the direction parallel to the substrate and a lower surface roughness. The Ga-cations act only as substitutional impurities, they are homogeneously distributed in the whole film, maintaining the wurtzite structure and increasing the carrier density. The formation of any spurious phase or segregation of Ga₂O₃ clusters that can act as carrier traps can be discarded. The characterization results allow us to conclude that the doped film has improved electrical and optical properties with respect to the undoped one. Therefore, the Ga-doped films are very suitable candidates as transparent conducting electrodes for solar cells, displays and other photoelectronic devices.     

Structure–property correlations of polymeric films for transparent insulation wall applications. Part 1: Solar optical properties

In this paper the results of a research project to establish a fundamental understanding of the physical relationships between the material structure and solar optical properties of polymeric transparent insulation (TI) materials are described. First, a systematic characterization of potential materials for TI applications in respect to their relevant physical properties in the solar radiation range was done. Second, based on the investigation of polymer films with different thicknesses model functions for the solar optical properties were established. Third, the solar optical properties were interpreted on base of polymerphysical relations. The characterization in the solar range and the calculation of solar optical film properties have shown, that the solar extinction is dominated by scattering occurring mainly at the surface. A linear relationship between the solar optical thickness and the film thickness was obtained for film thicknesses ranging from 12 to 150 μm. For various amorphous and semi-crystalline films the surface roughness correlated well with the solar optical thickness.     

STRUCTURAL AND MICROSTRUCTURAL EFFECTS ON THE THERMAL CONDUCTIVITY OF ZIRCONIA THIN FILMS

Thermal properties of thin films are involved in a large number of applications such as electronic and electrooptical devices, or thermal barrier coating. It is known that the structure and the microstructure of thin solid films have a strong influence on the thermal conductivity, which may be considerably lower than for bulk materials. The aim of this study is to highlight the role of structure and microstructure on the thermal conductivity of ZrO 2 thin films (stabilized with Y 2 O 3 or not). Investigations have focused on the influence of film thickness, substrate roughness, and crystallites size on the thermal properties of dielectric thin film samples. For this purpose, a new photothermal method has been developed to measure the thermal conductivity of such films on various kind of substrates with an accuracy better than 10%. It has been observed that a decrease in the dielectric thickness leads to a drastic drop of the apparent thermal conductivity, k a , whatever the ZrO 2 phase is. k a is affected by an additional thermal resistance, R fs , especially between ZrO 2 and alumina substrate. This resistance R fs varies linearly with the substrate roughness. Finally, the influence of crystallite size and grain boundaries on k a have been shown.     

Magnesium–titanium alloy thin-film switchable mirrors

In this paper, we show gasochromic and electrochromic switching properties of Pd top capped magnesium–titanium (Mg–Ti) thin films prepared by DC magnetron sputtering. These films show excellent switchable mirror properties. By exposing to 4% H₂ in Ar, Pd (4 nm)/Mg_0.82Ti_0.18 (40 nm) film changed from the metallic state to the transparent state drastically within 5 s. By exposing to air, it goes back to the metallic state within 60 s. The transmittance spectrum in the hydride state is quite flat in the wavelength range from 400 to 2500 nm. It looks complete color neutral and its chromaticity coordinates are x=0.326 and y=0.340. Simple electrochromic device of Mg–Ti thin film using a liquid electrolyte works very well. It can be switched between the mirror state and the color-neutral transparent state.     

薄膜厚度对ZnO:Ti透明导电薄膜光电性能的影响

利用直流磁控溅射法在室温水冷玻璃衬底上制备出可见光透过率高、电阻率低的掺钛氧化锌(ZnO∶Ti)透明导电薄膜。SEM和XRD研究结果表明,ZnO∶Ti薄膜为六角纤锌矿结构的多晶薄膜,且具有c轴择优取向。讨论了薄膜厚度对掺钛氧化锌透明导电薄膜光学、电学性能的影响。当薄膜厚度为835nm时,薄膜具有最低电阻率3.34×10-4Ω.cm。所制备薄膜附着性能良好,在波长为500～800nm的可见光中平均透过率均超过91%,ZnO∶Ti薄膜可用作薄膜太阳电池和液晶显示器的透明电极。     

pH值的变化对ZnS薄膜光学性质的影响

采用化学水浴法（CBD）制备ZnS薄膜,用NKD-7000v薄膜分析系统测试薄膜的透过率和反射率,拟合出薄膜厚度和吸收系数。研究了制备过程中不同的pH值调节剂对薄膜光学性质的影响。结果表明:加入pH值调节剂使薄膜禁带宽度增加,可达3.95eV,即对薄膜颗粒有细化作用。比较透过率和反射率,表明加NaOH把pH值控制在11和加NH₃把pH值控制在10.9时溶液沉积环境基本相似,反之亦然。但是加入氨水更有利于薄膜沉积速率的提高,且当pH值为11时加入调节剂,可以提升溶液进入亚稳态的pH值。     

CdS/CdTe太阳电池中CdS多晶薄膜的结构和光学性能

采用XRD,AFM,XPS和光学透射谱对化学水浴法制备的CdS多晶薄膜进行了测试分析。刚沉积的CdS多晶薄膜均匀、透明、致密,主要呈现立方结构;Cd和S的原子百分比约为1 10;能隙(Eg)约为2 47eV。在不同温度下后处理会出现六方结构和3CdSO4·8H2O衍射峰,同时晶面择优取向发生了变化。通过沉积高质量的CdS薄膜,获得了效率约13 4%的CdS/CdTe小面积太阳电池。