溶胶—凝胶法制备掺铝氧化锌薄膜及微观形貌研究

利用溶胶—凝胶旋涂技术在玻璃衬底上制备了不同铝掺杂量ZnO薄膜,再利用氮气气氛在500℃条件下对样品进行热处理。利用X射线衍射仪(XRD)、扫描探针显微镜(SPM)和紫外一可见光谱仪对薄膜结构形貌及光学性能进行分析表征。结果表明,所制薄膜具有六方纤锌矿结构,且随着掺杂量的变化,薄膜择优取向发生转变;薄膜可见光透过率与掺杂量呈负相关关系,掺杂量越高,可见光透过率越低;SPM结果显示在2.at%铝掺杂量下的样品表面出现柱状结构形貌,且晶粒粒度最小,表面粗糙度最低,表明薄膜表面形貌形成过程与铝掺杂量密切相关。     

聚乙烯醇分散对LiFePO_4薄膜气敏性的影响

为了优化LiFePO_4薄膜制备条件,提高LiFePO_4薄膜气敏元件的灵敏度,用水热法合成LiFePO_4并把它分散在聚乙烯醇(PVA)当中.利用旋转-甩涂法将LiFePO_4-PVA分散溶液涂抹于锡掺杂玻璃光波导表面,研制出LiFePO_4薄膜/锡掺杂玻璃光波导敏感元件;利用平面光波导检测系统对其气敏性进行研究.研究结果表明,分散剂质量分数为2%,超声波振荡时间为2 h,分散温度为25℃时,所制备出的敏感元件对二甲苯等苯类气体显出良好的气敏特性,其对二甲苯体积分数的检测范围为1×10~(-8)~1×10~(-3),分散之后,敏感元件对二甲苯等气体的检测灵敏度有所提高.     

旋涂法制备紫外荧光增强薄膜几种溶剂的比较

紫外荧光增强薄膜是一种有效提高硅基探测器紫外响应效率的荧光增强技术.对于旋涂法制备薄膜来说,溶剂的选择很重要,对使用不同溶剂旋涂制备的薄膜分析其紫外光谱透过率,成膜效果和荧光物质分布.四氢呋喃作为溶剂在旋涂的过程中全部挥发,虽不影响紫外光谱的透过率,但荧光物质的分布和表面粗糙度不理想.硝化棉相比于PMMA(聚二甲基硅氧烷,polydimethylsito xane)和PDMS(聚甲基丙烯酸甲酯,Polymethy Imethacrylate)紫外透过率低.PMMA常温状态下为固体,需要使用氯代烃或者芳烃溶解再旋涂,溶解时间较长且成膜效果不好;PDMS为胶体同荧光物质混合后直接旋涂,再加热80℃固化成膜,成膜效果好表面,粗糙度低,且荧光物质分布均匀.     

脉冲激光沉积CN_x薄膜的微观组织结构表征

利用脉冲激光烧蚀CNx靶,在室温至450℃基片温度时沉积CNx薄膜.利用扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子谱(XPS)和拉曼光谱(Raman)等对CNx薄膜的表面形貌、化学成分、结晶性以及价键状态进行了分析.结果表明:所得CNx薄膜呈非晶状态,表面形貌与沉积温度密切相关,基片温度高于150℃时薄膜表面较为光滑.随着基片温度的增加,薄膜中C—N键的面积分数从31.2%逐渐减少至14.1%,N—sp3C和N—sp2C键的面积分数随之减少,300℃时最利于形成sp3键.Raman光谱中比值ID/IG总体呈上升趋势,G峰的位置向高波数(高频)方向移动且半高宽(FWHM)下降,薄膜由CNx薄膜的无序结构逐渐向高有序化程度类石墨结构转变,石墨化程度增加.     

HClO4掺杂PANI/PdPc复合膜及其气体传感器研究

本文阐述了用化学合成法合成HClO4掺杂聚苯胺(PANI)和酞菁钯(PdPc),以松油醇为溶剂,将它们以不同比例相互杂化混合,再以微加工技术和溅射镀膜技术制作了平面微电极陶瓷基片,用涂膜工艺制作了7种不同混合比例的有机复合膜元件(PANI)x(PdPc)1-x.用静态配气法在气体浓度为0.01%时,对多种毒性气体逐一进行气敏特性测试.结果表明,PdPc对NO2呈N型半导体,灵敏度为0.06倍;HClO4掺杂PANI对SO2呈N型半导体,灵敏度为0.0023倍;x=1/6时,敏感膜对SO2、NO、Cl2也呈N型半导体,灵敏度分别为0.02倍,0.09倍,0.046倍.可通过选择不同的配比实现传感器的气敏选择性.     

蒸发诱导组装合成高度有序纳米TiO2薄膜

将溶胶-凝胶技术与自组装技术相结合,采用蒸发诱导组装合成方法,以四氯化钛为无机前驱体、高分子聚合物为结构导向剂成功制备了表面形貌规整透明的纳米晶二氧化钛薄膜.利用XRD、AFM、N2吸附-脱附仪等测试手段对样品晶型、粒径和形貌进行了表征,结果表明:经450℃热处理的样品表面非常规整,粒径在13nm左右且分布均一.所得锐钛矿晶体尺寸随焙烧温度的升高而增大,而BET比表面积随焙烧温度的升高而减小,800℃下存在锐钛矿相向金红石相的转变.     

掺杂与退火温度对VO2薄膜性能的影响

采用真空蒸发法在普通玻璃表面制备了VO2薄膜,研究了退火温度和掺杂对薄膜表面形貌、晶体结构、电学性能和光学性能的影响.结果表明:经400℃、420℃、450℃、500℃退火得到的VO2薄膜其表面形貌和晶体结构存在明显的差异,其中420℃退火后的薄膜结晶形态良好,主要成分是VO2,在65℃左右表现出明显的电阻突变,常温下在波长1 700 nm附近薄膜的光透过率达59.9％;在VO2薄膜中掺入W6 ,相变温度有所降低,但掺杂使薄膜光透过率降低.     

中频磁控反应溅射制备硅基氮化铝薄膜

利用中频磁控反应溅射技术,以高纯Al为靶材、高纯N2为反应气体,在Si(111)衬底上成功制备出氮化铝薄膜.通过X衍射分析和原子力显微镜测试发现:提高N2分压和升高衬底温度有利于AlN(110)的形成;随着衬底温度的改变,AlN薄膜的表面粗糙度也在变化,当衬底温度为230℃时,RMS表面粗糙度最小.实验结果表明:升高衬底温度有利于制备(110)面择优取向的AlN薄膜,退火是影响氮化铝薄膜表面粗糙度的重要因素.     

热处理气氛对溶胶——凝胶法Al∶ZnO膜特性的影响

采用溶胶—凝胶旋涂技术在玻璃衬底上制备Al∶ZnO薄膜(AZO)。在500℃条件下,利用氮气和氢气两种气氛分别对样品进行热处理,并对热处理后的薄膜特性进行研究。结果表明,上述两种气氛下所制薄膜都具有六方纤锌矿结构与C轴择优取向性;扫描探针显微结果表明,氮气气氛下薄膜形貌呈金字塔形,与氢气气氛所制薄膜差异明显;紫外可见光透射光谱图结果表明,氢气气氛下所制薄膜可见光透过率超过60%,高于氮气气氛所制样品,这可能与薄膜表面形貌有关。     

磁控溅射技术制备织构化表面Al掺杂ZnO薄膜

以Zn-Al(Al:2wt.%)合金为溅射靶材,采用直流反应磁控溅射的方法,在普通玻璃衬底上制备Al掺杂ZnO(AZO)薄膜。通过对衬底温度的调制,在较高衬底温度下(～280℃),无需经过常规溅射后腐蚀工艺过程,即可获得表面形貌具有特征陷光结构的AZO薄膜,其表面呈现类金字塔状,粗糙度RMS=65.831nm。通过测试薄膜的结构特性、表面形貌及其光电性能,详细地研究了衬底温度对AZO薄膜性能的影响。X射线衍射(XRD)和扫描电子显微镜(SEM)测试表明,所有样品均为多晶六角纤锌矿结构,薄膜呈(002)晶面择优生长,其表面形貌随衬底温度的不同而改变。衬底温度为200℃及其以上工艺条件下获得的AZO薄膜,在可见光及近红外范围的平均透过率大于90%,电阻率优于1.5×10-3Ωcm。     

Sensing characterization of Sn/In/Ti nanocomplex oxides for CO, CH_4 and NO_2

The nanocomplex oxides of Sn-In and Sn-In-Ti were prepared by controlled co-precipitation method as sensing materials of semiconductor gas sensors for detection of CO, CH4 and NO2. Through manipulating the Sn/In cation ratio, metal salt total concentration, precipitation pH value and aging time, the nanocrystalline powders were successfully derived with chemical homogeneity and superior thermal stability, compared with the single component oxides. The particle size and morphology, surface area, and thermal and phase stabilities were characterized using TEM, TG-DTA, BET and XRD. The sensing tests showed that the Sn-In com-posites exhibit high sensitivity and selectivity for CO and NO2. The introduction of TiO2 enhanced CH4 sensitivity and selectivity, particularly, additives of Pd and Al2O3 as a dopant and surface modification greatly enhanced the sensing properties. The sensitivity depended on the composition of composites, calcination temperature and operating temperature. The optimal values were (25%In2O3- 75%SnO2)-20%TiO2 for ternary composite, 600 and 300℃, respectively. Temperature-programmed de-sorption (TPD) studies were employed to explain the gas adsorption behavior dis-played by the surface of nanocomposites and X-ray photoelectron spectroscopic (XPS) analysis was used to confirm the electronic interactions existing between oxide components. The sensing mechanism of the nanocomposites was attributed to chemical and electronic synergistic effects.     

Zn掺杂对SnO_2纳米线的气敏性能的影响

为了提高SnO2纳米线基气敏传感器在实际应用中存在着灵敏度低、选择性差等问题,采用物理热蒸发法制备纯SnO2纳米线和不同质量百分比（7%,8%,9%,10%）的Zn掺杂SnO2纳米线,将制得的气敏基料制备成旁热式气敏元件,应用静态配气法对浓度均为500ppm的无水乙醇蒸汽、CO及CH4分别进行气敏性能测试.实验结果显示,Zn掺杂SnO2纳米线相比纯SnO2纳米线的气敏性能有了明显提高（乙醇提高2.46倍,CO提高13.88倍,CH4提高1.43倍）,并得出无水乙醇气敏性能在工作温度为280℃最高,CO,CH4在300℃最好.当Zn的掺杂比例为质量百分含量为9%时,各种比例材料所制成的气敏元件气敏性能最高.     

聚吡咯薄膜的制备及其氨气敏感特性的研究

运用聚电解质自组装膜对基片表面进行化学改性,通过原位聚合法及自组装方法在基片表面沉积聚吡咯薄膜,利用紫外可见分光光度计(UV-Vis)和原子力显微镜(AFM)对聚吡咯薄膜进行了分析表征。采用平面叉指电极制备了PPy薄膜气体传感器,研究了其在常温下对有毒气体NH3的敏感性及对-30℃~+60℃温度范围内、5.9% R.H~59.6% R.H范围内的湿度其敏感特性的变化,讨论了薄膜沉积时间对气敏特性的影响。结果表明,该传感器对浓度为0~141 ppm的NH3具有较高的灵敏度,对氨气的响应及恢复特性也很好,当沉积时间为20 min时,该传感器的NH3敏感特性最好。     

Preparation and enhanced daylight-induced photo-catalytic activity of transparent C-Doped TiO<Subscript>2</Subscript> thin films

The transparent C-doped TiO₂ nanostructure films were fabricated on the silicate glass substrates by sol-gel spin-coated method. The as-prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectra (UV-vis) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated via the photo-catalytic oxidation of methylene blue in aqueous under daylight irradiation at room temperature. The results show that the daylight-induced photocatalytic activities of the as-prepared films are improved by the C-doping. The calcination temperatures significantly affect the morphology, microstructure and photocatalytic activity of the as-prepared samples. At 723 K, the C-doped TiO₂ films exhibit the highest photocatalytic activity due to the synergetic effects of good crystallization, appropriate oxygen vacancies and strong absorption in the near UV and visible-light region.     

Sol-gel derived bioactive hydroxyapatite/titania composite films on Ti6Al4V

The composite films consisting of the titania gel impregnated with hydroxyapatite （HAP） submicron particles were prepared on commercial Ti6A14V plates processed by a sol-gel route. HAP powders were synthesized based on wet chemical precipitation method with Ca（NO3）2.4H2O and （NH4）2HPO4 as starting reagents. After being calcined at 900℃, HAP powders were ultrasonically scattered in ethanol to produce HAP sol. The titania sol was prepared using titanium （IV） isopropoxide {Ti[OCH（CH3）2]4} as precursor. Both the titania sol and the HAP/titania mixture were sequentially spin-coated on the substrates and calcined at various temperatures. The characteristics and mechanical adhesion of the composite films were investigated. The results show that the as-prepared films are dense, homogeneous, well-crystallized, and there is a good interfacial adhesion between the film and the substrate. The in vitro bioactivities of these films were discussed based on the analysis of the variations of Ca and P concentrations in the simulated body fluid and their surface morphologies against immersion time.     

大面积金刚石膜生长过程中的缺陷和内应力

采用甲烷和氢气作为气源,在直径为50 mm的抛光单晶硅片上,利用新型微波等离子体化学气相沉积(MPCVD)装置制备出金刚石膜.用扫描电子显微镜观测金刚石膜的表面形貌,利用激光Raman光谱表征金刚石膜的质量以及X射线衍射检测金刚石膜的成分和晶界缺陷.结果表明V(CH4)/V(H2)为1%,基片温度为845℃时,生长金刚石膜的质量较好,并且具有完整的晶体形貌,但是扫描电子显微镜图×5 000倍时,观察到金刚石膜中明显的晶体缺陷存在,同时X射线衍射图表明金刚石膜的内应力较大.     

Preparation and Enhanced Daylight-Induced Photo-Catalytic Activity of Transparent C-Doped TiO_2 Thin Films

The transparent C-doped TiO2 nanostructure films were fabricated on the silicate glass substrates by sol-gel spin-coated method. The as-prepared films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectra (UV-vis) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated via the photocatalytic oxidation of methylene blue in aqueous under daylight irradiation at room temperature. The results show that the daylight-induced photocatalytic activities of the as-prepared films are improved by the C-doping. The calcination temperatures significantly affect the morphology, microstructure and photocatalytic activity of the as-prepared samples. At 723 K, the C-doped TiO2 films exhibit the highest photocatalytic activity due to the synergetic effects of good crystallization, appropriate oxygen vacancies and strong absorption in the near UV and visible-light region.     

压缩喷雾热分解法制备SnO2薄膜研究

以SnCl2·2H2O为原料,采用压缩喷雾热分解的方法在玻璃衬底和石英片衬底上制得氧化锡薄膜。采用X射线衍射仪（XRD）和扫描电镜（SEM）分别对薄膜的内部结构和表面形貌进行了表征。研究表明,500℃下制备的薄膜比较致密平整;320℃下,喷雾50min制得的薄膜的X射线衍射峰强度较强;相同喷雾时间下,当温度达到380℃时,X射线衍射峰的强度大幅度提高。     

功能化单壁碳纳米管的气敏性研究

通过不同官能团功能化,在单壁碳纳米管(SWNTs)上连接不同基团并制成薄膜。采用恒定电位法,将它们暴露在NO2中,N2作为载气,不同温度下(30℃、50℃、70℃、90℃)检测电流随时间的变化情况(I-t图)。结果表明,随着温度的升高各薄膜对NO2的响应速率加快;含对苯基的SWNTs薄膜在50℃灵敏度最大,而连接有羧基、氨基的SWNTs薄膜在30℃灵敏度最大;对硝基苯基功能化后的SWNTs对NO2的响应程度最大,明显强于其他薄膜。     

纳米Co3O4的制备及其臭氧辅助下对乙醇的气敏性能

以CoOCl₂·6H₂O为钴源,NaOH为沉降剂,通过水热法制备出Co₃O₄纳米粉末,并以Co₃O₄纳米粉末为敏感材料制作了旁热式气敏元件。X射线衍射和透射电子显微镜表征显示Co₃O₄纳米粉晶粒平均粒径15.6 nm。气敏测试结果表明元件在80 ℃、臭氧质量浓度为4.280×10^-8 g/mL的条件下,对2.009×10^-7 g/mL乙醇的灵敏度达到29,而空气中时元件对乙醇的灵敏度仅为4,O₃的加入提高了Co₃O₄气敏元件在80 ℃的灵敏度,并将对乙醇气敏的最佳工作温度由100 ℃降低至80 ℃,实现了Co₃O₄在低温下（80 ℃）的气敏性能检测。