立方相WO_3薄膜的制备及表征

以偏钨酸铵(NH_4)_6W_4O_(24)·6H_2o为钨源,聚乙二醇(PEG)为配位聚合物,采用聚合物前驱体法制备了立方晶相WO_3(c-WO_3)薄膜,利用X射线衍射、扫描电镜、能谱分析及高分辨透射电镜等手段对结构进行了表征,并考察了煅烧温度、溶液pH值及镀膜衬底对WO_3薄膜晶体结构与形貌的影响.结果表明,以FTO导电玻璃为衬底,450℃热处理3 h的样品为c-WO_3,薄膜光滑平整,均匀良好,表面颗粒粒径为60 nm,厚度为2.9μm,晶体生长有序度较高;热处理温度在400～550℃和不同pH值条件下制得的薄膜均为立方晶体结构;样品的颗粒粒径随前驱体溶胶pH值升高而减小;以石英玻璃和石墨衬底镀膜得到的样品均为单斜晶体结构,表明衬底对WO_3薄膜晶体结构具有明显的影响.     

热处理温度对电致变色玻璃用WO_3薄膜性能的影响研究

采用过氧化聚钨酸法制备WO_3溶胶,在ITO导电玻璃基体上采用旋涂法制备WO_3薄膜。主要探讨了退火温度对WO_3薄膜结构与电变色性能、响应时间和循环稳定性的影响。热重和X射线衍射分析结果表明:热处理温度应低于320℃时,WO_3薄膜为非晶态。在240~320℃范围内,随着热处理温度升高,光密度变化量降低即电致变色性能变差,着-褪色时间延长,而薄膜的循环稳定性越来越好。经320℃退火处理的WO_3薄膜形成晶态,稳定性好,此时该电致变色薄膜的着-褪色响应时间分别为2.76和1.30s。     

原子层沉积低温制备高取向锐钛矿TiO_2薄膜

利用原子层沉积(ALD)法分别在Si和石英衬底上制备了Ti O_2薄膜,并在N2氛围下对Ti O_2薄膜样品进行退火处理。采用X射线衍射、原子力显微镜和场发扫描电子显微镜对不同退火温度下样品晶体结构、表面形貌进行了分析。利用紫外-可见分光光度计对不同退火温度下的Ti O_2薄膜进行了光学性能测试,并分析了退火温度对其光学带隙的影响。发现利用ALD方法制备的沉积态Ti O_2薄膜为高度择优取向的锐钛矿结构;当退火温度升高到600℃时,Ti O_2薄膜晶体结构类型仍为锐钛矿型,晶粒略有变大;退火态Ti O_2薄膜粗糙度比沉积态Ti O_2薄膜的粗糙度大,而且粗糙度随退火温度升高而增大。根据薄膜的透射光谱拟合了光学带隙,退火后薄膜禁带宽度略有变宽,吸收边缘发生蓝移。     

后退火对射频磁控溅射制备β-Ga_2O_3薄膜的影响

采用射频磁控溅射法制备了氧化镓(Ga_2O_3)薄膜,计算了薄膜的O/Ga摩尔比,比值为1.57。研究了后退火对薄膜结构,形貌特征和光学带隙的影响。X射线衍射(XRD)结果表明,退火前的Ga_2O_3薄膜是一种无定形结构。在600℃氧气氛中退火2h后,薄膜开始出现β-Ga_2O_3的(■01)衍射峰;随着退火温度的升高,β-Ga_2O_3(■01)衍射峰进一步增强,并且半高宽从0.61°减小到0.49°。原子力显微镜(AFM)测试结果表明,退火前后薄膜表面的均方根粗糙度从3.47 nm增加到了7.08 nm,晶粒尺寸从19 nm增加到了53 nm。紫外-可见分光光度计(UV-VIS)测试结果表明Ga_2O_3薄膜在250 nm-1500 nm波长范围内的平均透过率在85%以上。利用Tauc公式计算了Ga_2O_3薄膜的光学带隙,带隙宽度在(4.85-5.06)eV之间,且随退火温度增加而减小。分析了表面形貌、光学带隙与薄膜结构之间的关系。     

WO_(3)敏感电极的制备及其性能研究北大核心CSCD

迈向微型化、集成化及具有高选择性和灵敏度的固体电解质气体传感器已成为未来的发展趋势。文章采用磁控溅射法成功制备了WO_(3)气体传感器敏感电极材料,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)等表征手段研究了WO_(3)的结构、成分和形貌并测试了该气体传感器对NO_(2)的气敏性能。XRD结果表明,当退火温度大于400℃时,WO_(3)出现(200)衍射峰,且该衍射峰随退火温度增加而显著增强,表明WO_(3)结晶质量增加。SEM测试结果表明,随着退火温度的升高,薄膜的晶粒尺寸逐渐增大。当退火温度达到500℃时,采用谢乐公式计算其晶粒尺寸达到23 nm。EDS结果表明,退火温度对薄膜的成分也有较大影响,O:W原子比例呈现增大趋势,由2.7增加到3.2,这与XPS结果相符合。通过高温气敏性能测试表明,所制得的WO_(3)敏感电极对NO_(2)表现出了明显的气体响应。本研究为制备微型化、高选择性和灵敏性的固体电解质气体传感器提供了一定的研究基础。     

电子束蒸镀纳米TiO_2薄膜结构、相组成及亲水性研究

利用电子束蒸镀技术在石英玻璃和单晶Si〈100〉上制备了纳米TiO2薄膜,研究了衬底温度和退火温度对其结构、相组成和亲水性能的影响。结果表明,衬底温度为40~240℃时,石英玻璃上制备的薄膜为无定型TiO2,单晶Si〈100〉上制备的薄膜为弱结晶性的金红石TiO2,两类薄膜的亲水性均很差。退火温度显著影响薄膜的相组成及亲水性能。石英玻璃上不同衬底温度制备的TiO2薄膜经550,650℃退火后均转变为锐钛矿TiO2,具有很好的亲水性能。单晶Si〈100〉上不同衬底温度制备的TiO2薄膜经550~950℃退火后,均由金红石和锐钛矿TiO2混晶组成,且随退火温度升高,薄膜中锐钛矿TiO2含量逐渐增加;随退火温度升高,衬底温度为40℃时制备的TiO2薄膜的亲水性能逐渐降低,而衬底温度为240℃时制备的TiO2薄膜的亲水性能逐渐增强。     

ZnO纳米晶薄膜的制备及特性分析

在低温下制备了粒径小于10nm的ZnO纳米晶,用旋涂法制备ZnO纳米晶薄膜,XRD分析ZnO晶相是纤锌矿结构;SEM与AFM表明,纳米晶薄膜在300％退火后薄膜的厚度明显减小到130nm,表面粗糙度降低到3．27nm,粒径明显增大;紫外-可见吸收和透射比光谱表明,随着退火温度的增加,吸收边发生了红移,吸收肩更明显,薄膜具有高的透射率（75—85％）;薄膜方阻随温度增加而增大,300℃以下退火方阻增加很小（小于8．5Ω／sq）,400℃以上退火方阻大幅增加（大于21．1Ω／sq）,因此,ZnO纳米晶薄膜最优退火温度点为300℃。     

快速热处理对BaSrTiO3薄膜微结构的影响

采用射频溅射法在Si基片上制备BaSrTiO3(BST)薄膜,利用X射线衍射和原子力显微镜(AFM)研究了快速热处理温度和时间对BaSrTiO3薄膜微结构的影响.结果表明:BST薄膜的衍射峰强度和结晶度随退火温度的升高而提高.随退火温度的升高,BST薄膜的表面粗糙度经历先降低后增大的过程,而BST薄膜的晶粒尺寸单调减小.当退火温度为700℃时,随退火时间的增加,BST薄膜的晶粒尺寸几乎不发生变化,而表面粗糙度单调减小.     

电子束蒸发法制备掺钇稳定氧化锆薄膜的光学特性研究

利用电子束蒸镀方法在单晶硅和石英玻璃上制备了掺不同Y_2O_3浓度的掺钇稳定ZrO_2薄膜(YSZ),用X射线衍射、原子力显微镜、扫描电子显微镜和透射光谱测定薄膜的结构、表面特性和光学性能,研究了退火对薄膜结构和光学性能的影响.结果表明:一定浓度的Y_2O_3掺杂可以使ZrO_2薄膜稳定在四方相,退火显著影响薄膜结构,随着温度的升高薄膜结构依次经历由非晶到四方相再到四方和单斜混合相转变;AFM分析显示薄膜表面YSZ颗粒随着退火温度的升高逐渐增大,表面粗糙度相应增大,晶粒大小计算表明,退火温度的提高有助于薄膜的结晶化,退火温度从400℃到1100℃变化范围内晶粒大小从15.6nm增大到46.3nm;同时利用纳秒激光对薄膜进行了破坏阈值测量,结果表明电子束蒸镀制备YSZ薄膜是一种制备高抗激光损伤镀层的有效方法.     

快速热处理对(Ba,Sr)TiO3薄膜晶化行为的影响

采用射频溅射法在Si(111)基片上制备了(Ba,Sr)TiO3(BST)薄膜,并对制备的薄膜进行了快速退火热处理.采用X射线衍射和原子力显微镜分析了退火温度、退火时间和加热速度对BST薄膜晶化行为的影响.研究结果表明,BST薄膜的晶化行为强烈依赖于退火温度、退火时间和加热速度.BST薄膜的结晶度随退火温度的升高而提高.适当的热处理可降低BST薄膜的表面粗糙度,BST薄膜的表面粗糙度随退火温度的升高经历了一个先降低后增大的过程,但退火后BST薄膜的表面粗糙度都小于制备态薄膜的表面粗糙度.BST薄膜的晶粒尺寸随退火温度的升高经历了一个先增大后减小的过程.随退火时间的延长,BST薄膜的特征衍射峰越来越强,薄膜的晶化程度越来越高.随退火时问的延长,BST薄膜的晶粒尺寸和表面粗糙度也经历了一个先增大后减小的过程.BST薄膜的晶粒大小主要由退火温度决定.高的升温速率可获得较小的晶粒.     

Material and sensing properties of Pd-deposited WO3 thin films

The physicochemical and electrical properties of Pd-deposited WO3 thin films were investigated as a function of Pd thickness, annealing temperature, and operating temperature for application as a hydrogen gas sensor. WO3 thin films were deposited on an insulating material using a thermal evaporator. X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were used to evaluate the crystal structure, microstructure, surface roughness, and chemical property of the films, respectively. The deposited films grew into polycrystalline WO3 with a rhombohedral structure after annealing at 500 degrees C. Adding Pd had no effect on the crystallinity, but suppressed the growth of WO3 grains. The Pd was scattered as isolated small spherical particles of PdO2 on the WO3 thin film after annealing at 500 degrees C, while it agglomerated as irregular large particles or diffused into the WO3 after annealing at 600 degrees C. PdO2 reduction under H2 and reoxidation under air were dependent on both the Pd deposition thickness and annealing conditions. The WO3 thin film with a 2-nm-thick Pd deposit showed a good response and recovery to H2 gas at a 250 degrees C operating temperature.     

Amorphous tungstate precursor route to nanostructured tungsten oxide film with electrochromic property

Electrochromic tungsten oxide (WO3) films on ITO glass were fabricated by spin-coating with a tungsten peroxy acid solution, which was prepared by adding an equivolume mixture of hydrogen peroxide and glacial acetic acid to tungsten metal powder. The structural evolution of the tungstate precursor upon heat treatment was studied by X-ray diffraction (XRD) and X-ray absorption near edge structure (XANES) analyses, which indicated that the as-synthesized tungstate transformed into nanocrystalline WO3 upon heating. It is, therefore, quite clear that as-synthesized tungstate can be a good precursor for electrochromic WO3 films. A series of WO3 thin films were prepared on ITO glass by spin-coating with different concentrations of tungsten peroxy acid solution and then post-annealing at various temperatures. Depending on the concentration of the tungstate coating solution (200-500 mg mL(-1)) and the annealing temperature (100-300 degrees C), the thickness and WO3 content as well as the electrochromic properties of WO3 films can be controlled. As a result, the optimum fabrication conditions were determined to be a tungstate solution concentration of 300-400 mg mL(-1) and a post-annealing temperature of 200 degrees C. Finally, an inorganic-inorganic hybrid electrochromic device (ECD) composed of optimized WO3 and Prussian Blue (PB) with desirable coloration efficiency was successfully developed.     

Investigation of H2S gas sensing performance of Ni:WO3 films at room temperature: nickel precursor effect

Journal of Materials Science: Materials in Electronics - In this work, pure and nickel-doped WO3 films were produced by chemical bath deposition on In-doped SnO2 (ITO) substrates without annealing...     

WO3薄膜制备及其电致变色性能研究

采用直流反应磁控溅射方法在室温下制备WO3薄膜。研究溅射功率对WO3薄膜结构及电致变色性能的影响规律,考察退火后WO3薄膜的结构演变及电致变色性能变化。结果表明溅射功率为270W时薄膜表现出较好的电致变色性能,其调制幅度达78.5%,着色时间为9s,褪色时间为3.2s。将该功率下制备的WO3薄膜进行退火处理,其结构由非晶态转变为晶态,但调制幅度、响应时间特性都发生一定程度的退化。非晶态WO3薄膜相比晶态结构具有更快的响应时间和更宽的调制幅度,但晶态薄膜具有更好的循环稳定性。     

Si（111）衬底上沉积LaNiO3薄膜的取向控制和导电性能研究

通过金属有机物沉积的方法在Si（111）衬底上成功制备出了高度（100）和（110）取向的LaNiO3薄膜。研究了不同热处理过程、薄膜厚度、前驱体溶液对LaNiO3取向的影响,以及厚度热处理温度、（100）方向的取向度与薄膜方阻之间的关系。LaNiO3薄膜的相结构由XRD（X射线衍射）分析,薄膜的晶粒大小和表面粗糙度由AFM（原子力显微镜）分析。     

通过嵌段共聚物自组装制备哑铃状Au-Fe304纳米粒子排列

通过嵌段共聚物自组装制备哑铃型Au-Fe3O4纳米粒子排列,先通过旋涂含有哑铃型纳米粒子（DBNPs）的聚苯乙烯-b-聚（2-乙烯基吡啶）（PS—b—P2VP）混合溶液得到复合薄膜,再将复合薄膜在高温下退火,实验发现,无论是预先合成的表面带有油酸基团,还是11-巯基十-烷酸修饰的哑铃型纳米粒子,都可以选择性的进入到PS—b—P2VP嵌段共聚物中的P2VP柱状微区中。实验结果表明,在退火过程中,哑铃型纳米粒子可以进入到嵌段共聚物中的一个微区中,并不取决于其表面的化学性质。     

射频磁控溅射法制备碲化铅薄膜的X射线衍射分析

采用射频磁控溅射法,在单面抛光的Si(111)衬底上制备了PbTe薄膜,利用X射线衍射法分析了溅射工艺参数如溅射功率、溅射时间、衬底温度以及退火温度对PbTe薄膜的结晶质量的影响。结果表明:在溅射功率为30W,溅射时间为10 min,衬底未加热时制备的薄膜具有最好的〈100〉方向的择优取向性;退火处理可以改善薄膜的结晶质量,并且退火温度越高,薄膜的结晶质量越好。     

Ni掺杂TiO2薄膜的甩胶喷雾热分解法制备和自清洁性能的研究

以钛酸丁脂（Ti（C4H9O）4）为先驱体,硝酸镍（NiNO3）为掺杂物,采用甩胶喷雾热分解方法在玻璃衬底上制备出了镍掺杂TiO2自清洁薄膜,通过扫描电镜（SEM）、X射线衍射（XRD）、紫外-可见透射光谱（UV-Vis）、光催化和亲水性能测定等手段对样品进行分析,结果表明,500r/min为理想衬底转速,350℃是理想的衬底沉积温度,500℃是理想的样品退火温度。随着镍掺杂量的不断增加,TiO2薄膜的亲水性能也越好,当镍掺杂量达2%-3%时,TiO2薄膜的亲水性能达到最好。     

Surface and in depth chemistry of polycrystalline WO/sub 3/ thin films studied by X-ray and soft X-ray photoemission spectroscopies

The chemical composition of surface and underneath layers of WO/sub 3/ thin films, deposited by thermal evaporation and annealed in air at different temperatures, has been studied by means of soft X-ray and X-ray photoemission spectroscopies. Both the W 4f and valence band spectra have been analyzed. The analysis has been performed on samples as inserted and after an annealing process in an ultra high vacuum. The results have shown that the surface always presents a nonstoichiometric WO/sub 3/ compound, whose spectral components do not depend on the sample preparation. Instead, the study of the underneath layers has shown that the WO/sub 3/ films annealed in air at 500/spl deg/C are highly stoichiometric and stable, while the samples heated in air at 300/spl deg/C are much more sensitive to the vacuum thermal treatment showing the presence of reduced WO/sub x/ phases, whose intensity and chemical states change after the in vacuum annealing procedure.