厚度对室温沉积ZnO:Al薄膜光电特性的影响

利用直流磁控溅射法, 在室温玻璃衬底上制备了具有良好附着性的多晶ZnO∶ Al(ZAO)薄膜. 比较了室温下获得的薄膜与衬底加热条件下所得薄膜的结晶程度, 研究了厚度对室温条件下制备的ZAO薄膜表面形貌、电学性能及紫外-可见-近红外光区透光性的影响. 结果表明, 室温条件下制备的ZAO薄膜也具有(002)面择优取向, 随着膜厚的增加薄膜晶粒化程度提高, 载流子浓度和迁移率增大, 电阻率下降, 薄膜在紫外光区的吸收边发生红移, 在可见光区的平均透过率降低, 在近红外光区的透过率随厚度的增加而减小. 厚度为1200 nm的ZAO薄膜具有最佳光电综合性能, 其电阻率为7.315×10~(-4) Ω·cm, 方块电阻为6.1 Ω/□, 可见光区平均透过率达到82%, 波长为550 nm处的透过率为87%.     

闪蒸法制备N型Bi2( Te0.95Se0.05)3薄膜的微结构及热电性能研究

采用闪蒸法在温度为473 K的玻璃基体上沉积了厚度为800 nm的N型Bi2(Te0.95Se0.05)3热电薄膜,并在373 ～573 K进行1h的真空退火处理.利用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)分别对薄膜的物相结构和表面形貌进行分析.采用表面粗糙度测量仪测定薄膜厚度,薄膜的电阻率采用四探针法进行测量,采用温差电动势法在室温下对薄膜的Seebeck系数进行表征.沉积态薄膜表明了(015)衍射峰为最强峰,退火处理后最强衍射峰为(006);沉积态薄膜由许多纳米晶粒组成,晶粒大小分布较均匀,平均晶粒尺寸大约45 nm,退火处理后出现了斜方六面体的片状晶体结构.退火温度从373 K增加到473 K,薄膜的电阻率和Seebeck系数增加,激活能也随退火温度的增加而增大,退火温度从523 K增加到573 K,薄膜的电阻率和Seebeck系数都缓慢下降.从373 ～473 K,热电功率因子随退火温度的升高而单调增加,退火温度为473 K时,电阻率和Seebeck系数分别是2.7 mΩ.cm和-180μV·K-1,热电功率因子最大值为12 μW.cmK-2.退火温度从523 K增加到573 K,热电功率因子的值逐渐下降.     

氧分压对射频磁控溅射制备氧化锌薄膜光电学性质的影响

利用射频磁控溅射在石英基片上沉积ZnO薄膜.为了研究氧分压对ZnO薄膜的结构和光电学性质的影响,在氧分压0.00,2.54,5.06,7.57 mPa的条件下制备了4个样品.样品的微结构、表面形貌和光电学性质分别用X射线衍射仪、原子力显微镜、分光光度计和Van der Pauw方法进行测量.结果表明,所有样品的主要衍射峰为(002)峰,随氧分压的增加,(002)峰的强度降低,且出现了(101)面的衍射峰.氧分压的升高,薄膜的表面粗糙度和载流子浓度减小,迁移率增大,电阻率从氧分压为0时的0.2 Ωcm增加到7.57 mPa时的1 400 Ωcm.所有样品在可见光区的平均透过率都大于83%,薄膜的折射率随氧分压的增加而增大,而消光系数和光学带隙则减小.     

低辐射膜系中(Al,Ti)N薄膜的研究

以制备出性能优异成本低廉的低辐射镀膜玻璃为目的.通过直流磁控反应溅射技术在玻璃(或单晶硅)表面制备(Al,Ti)N薄膜作为低辐射镀膜玻璃的内层介质层,在此基础上进行单因素变量分析铝靶功率、钛靶功率、氮气流量和溅射时间对薄膜可见光透过率、表面粗糙度的影响以及测定最优条件下薄膜的结晶状态、表面形貌和元素含量.结果表明,当铝靶功率为100 W、钛靶功率为80 W、氮气流量为2.5 ml/min、溅射时间为90 min时可见光范围内透过率均在96%以上,表面粗糙度11.3 nm,膜基结合力强,膜质优异适宜低辐射镀膜玻璃功能膜的附着.     

ITO透明导电薄膜的溶胶凝胶法制备及结构表征

以五水硝酸铟和乙酰丙酮为原料,以无水氯化锡为掺杂剂,采用溶胶凝胶工艺,用提拉法在石英玻璃基体上制备了ITO透明导电薄膜。采用DTA—TG、XRD、SEM、四探针电阻率仪、紫外分光光度计等仪器对ITO透明导电薄膜的相转变过程、物相、表面结构、微区形貌和物理性能进行了测定和分析。结果表明:采用溶胶凝胶工艺在石英玻璃基体上制备ITO透明导电薄膜是完全可行的。ITO薄膜具有由多个粒子堆积而成的多孔微观结构,其晶体结构为立方锰铁矿结构,[111]为明显的择优取向,经过5次镀膜后其厚度在150nm以下,薄膜的方电阻为110Ω,其电阻率约为1.65×10-2Ω·cm。薄膜的透光率在90%以上。     

磁控溅射与电子束蒸发制备Ti薄膜性能的研究

为了研究不同制备方法对薄膜性能的影响，分别利用磁控溅射法和电子束蒸发法在长有500 nm厚的SiO2薄膜的Si(100)晶圆上制备了生长速度为1.0 nm/s，厚度为100 nm的Ti薄膜，并对薄膜的厚度、表面形貌、电阻、反射率及应力进行了测试。相比于电子束蒸发法，磁控溅射法制备的薄膜表面晶粒更加均匀致密，表面缺陷少，粗糙度较小，薄膜具有更低的电阻、应力以及更高的反射率。试验结果表明，磁控溅射法制备的薄膜电性能优于电子束蒸发法。电子束蒸发法制备的薄膜应力具有较大的变化范围，可用于多层膜之间的应力匹配调试。同时，也可以通过减少薄膜表面结构缺陷，减小薄膜表面粗糙度来提高薄膜的性能。     

生长温度和退火气氛对ZnO:Al薄膜结构与性能的影响

采用直流磁控溅射法在玻璃衬底上制备ZnO:Al透明导电薄膜,研究生长温度和退火气氛对薄膜结构、形貌、光学和电学性能的影响。结果表明:不同温度下生长的ZnO:Al薄膜均为高度c轴取向的六角铅锌矿结构,400~900 nm波长范围内薄膜的平均透过率均超过85%。ZnO:Al薄膜的电学性能强烈依赖于生长温度,室温~500℃范围内,500℃下生长的薄膜具有最大的载流子浓度(2.294×1021 cm-3)和最低电阻率(4.095×10-4-.cm)。退火气氛对薄膜的性能影响显著,经过不同气氛退火后,薄膜的表面粗糙度降低,结晶质量和光学性能有所提高;在O2、N2、空气等气氛下退火,薄膜的载流子浓度降低,电阻率上升;Ar和真空退火时,薄膜载流子浓度上升,电阻率显著下降。     

氮气流量对TiN 薄膜组织结构及力学性能的影响

采用磁控溅射方法在不锈钢表面沉积TiN薄膜,通过扫描电子显微镜、显微硬度计、CSPM5500扫描探针显微镜、X射线衍射仪、往复式摩擦磨损仪等分析测试手段,研究氮气流量对薄膜形貌、成分、结构、硬度、表面粗糙度、耐磨损等性能的影响.结果表明,随着氮气流量的增加,薄膜的显微硬度、膜厚都逐渐降低,膜基结合力逐渐增加,膜基结合力在16 mL/min时达到最大67.2 N;表面粗糙度和平均摩擦系数均在8 mL/min时最低.随着氮气流量增加,薄膜主要生长取向由(200)晶面转向(111)晶面生长;TiN薄膜的颜色也随氮气流量增大而加深,8 mL/min和12 mL/min时为金黄色,4 mL/min和16 mL/min时颜色较差.      

Pr掺杂CdS薄膜的制备及其光电性能研究

结合化学水浴法和真空电子束热蒸发法在玻璃衬底上制备了含有不同厚度Pr掺杂层的CdS多晶薄膜,并对薄膜的结构、表面形貌和光电特性进行了研究。结果表明,未掺杂的CdS薄膜为沿[111]晶向择优生长的立方相闪锌矿结构,导电类型为N型。Pr掺杂并未改变CdS薄膜的物相结构和择优取向,但衍射峰强度增加;掺Pr后CdS薄膜的晶粒尺寸增大,致密性提高,并且薄膜在可见光范围内的透过率增加,光学带隙变大。同时还发现CdS中掺Pr后影响了薄膜的电学性能,掺杂浓度较低时CdS薄膜电阻率增大,掺杂浓度较高时薄膜的电阻率降低并且导电类型由N型转变为P型。     

沉积压力对磁控溅射Mg薄膜结构的影响

采用直流磁控溅射方法在氧化锆固体电解质表面制备了Mg金属薄膜,利用XRD和SEM研究了沉积压力(0.9～2.1Pa)对薄膜形貌和结构的影响.结果表明:随着沉积压力的提高,薄膜结晶程度逐渐变差,晶粒尺寸减小,表面粗糙度增大;薄膜呈(002)择优生长的柱状晶结构,且随着沉积压力的提高薄膜厚度先增加后减小.     

Analysis and Characterization of Relationships Between the Processing and Optical Responses of Amorphous BaTiO3 Nanothin Films Obtained by an Improved Wet Chemical Process

In the present work, we have tried to study and develop the processing of amorphous BaTiO₃ nanothin films, which have amorphous structure and nanometric thickness. It was seen that they exhibit enhanced optical responses. An improved method was used to prepare amorphous BaTiO₃ nanothin films, which, compared to other approaches, is simple, cost-effective, and environmentally friendly. It was found that amorphous BaTiO₃ films exhibit better optical transmittance in contrast to the similar nanocrystalline, polycrystalline, or thick films. This finding is due to the absence of grain boundaries, which have an important role in light scattering processes. AFM and SEM results indicate that the surface of the nanothin film is uniform, smooth, and amorphous. Moreover, the surface of the nanothin film exhibits a dense structure with no crack and voids. RMS roughness of the prepared nanothin film was quite small and equal to 0.7 nm. This value is very less than other reported RMS roughness values which were in the range of 5 to 11 nm. XRD results indicate that all of the prepared thin films in this work are amorphous, independent of number of dip-coated layers and preparation conditions. The work also aims to study and develop the processing of the amorphous BaTiO₃ nanothin films deeply. The results showed that annealing temperature has a more pronounced effect on transmittance, thickness, and shift in the absorption edge of the thin films than annealing time. It was found that the viscosity of the sol has remarkable influence on the transmission spectrum and shift in the absorption edge of the films. The transparency of the films decreases with an increase in the viscosity and concentration of the sol. It was found that size of particle within the sol and rate of the sol–gel reactions have important roles on the transmittance of the films.     

Effect of Ti cap layer thickness on microstructures and magnetic properties of Ti/Ni/Ti films

Nanogranular Ti(3 nm)/Ni(30 nm)/Ti(t nm )(t=1,3,5,7,10) films were prepared by facing magnetron sputtering from Ti and Ni onto glass substrates at room temperature.The structural and magnetic properties of films strongly depended on the Ti layer thickness.X-ray diffraction(XRD) patterns of all as-deposited films showed strong FCC Ni(111) peak.Vibrating sample magnetometer(VSM) measurements indicated that the perpendicular coercivity of the Ti(3 nm)/Ni(30 nm)/Ti(3 nm) film reached about 36 kA/m.With the increase of Co layer thickness,coercivity(Hc) first increased and then decreased.The grain size and magnetic clusters slightly increased and the value of roughness(Ra) was smallest at t=3 nm.     

采用磁控溅射法在细菌纤维素膜上制备高性能的铟锡氧化物薄膜

Microbial cellulose (MC) membranes produced by Acetobacter xylinum NUST4.1, were used as flexible substrates for the fabrication of transparent indium tin oxide (ITO) electrodes. Transparent and conductive ITO thin films were deposited on MC membrane at room temperature using radio frequency (RF) magnetron sputtering. The optimum ITO deposition conditions were achieved by examining crystalline structure, surface morphology and optoelectrical characteristics with X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV spectroscopy. The sheet resistance of the samples was measured with a four-point probe and the resistivity of the film was calculated. The results reveal that the preferred orientation of the deposited ITO crystals is strongly dependent upon with oxygen content (O2/Ar, volume ratio) in the sputtering chamber. And the ITO crystalline structure directly determines the conductivity of ITO-deposited films. High conductive [sheet resistance～120Ω.square-1(Ω.sq-1)] and transparent (above 76%)ITO rilms(240 nm thick) were Obtained with a moderate sputtering power (about 60 W) and with an oxygen flow rate of 0.25ml·min-1(sccm) during the deposition. These results show that the ITO-MC electrodes can find their potential application in optoelectrical devices.     

Effect of Ti cap layer thickness on microstructures and magnetic properties of Ti/Ni/Ti films

Nanogranular Ti (3 nm)/Ni(30 nm)/Ti(t nm) (t=1, 3, 5, 7, 10) films were prepared by facing magnetron sputtering from Ti and Ni onto glass substrates at room temperature. The structural and magnetic properties of films strongly depended on the Ti layer thickness. X-ray diffraction (XRD) patterns of all as-deposited films showed strong FCC Ni(111) peak. Vibrating sample magnetometer (VSM) measurements indicated that the perpendicular coercivity of the Ti (3 nm)/Ni (30 nm)/Ti (3 nm) film reached about 36 kA/m. With the increase of Co layer thickness, coercivity (H_c) first increased and then decreased. The grain size and magnetic clusters slightly increased and the value of roughness (R_a) was smallest at t=3 nm.     

磁控溅射Ti/WO_3薄膜的微结构及光学性能

采用直流反应磁控溅射技术在玻璃基片上制备不同氧分压的Ti掺杂的WO3薄膜。用X射线衍射(XRD)、分光光度计、台阶仪等对薄膜的结构、光学性质进行表征;分析不同的氧分压对气敏薄膜透光率和结构的影响。结果表明,氧分压增大,膜厚减小,薄膜的平均晶粒尺寸增大,晶面间距增大,光学带隙变小。并用包络线法和经验公式法计算出薄膜的光学常数,结果表明,折射率和消光系数随氧分压的增加而增大。     

酸性条件下水浴沉积时间对硫化镉薄膜特性的影响

基于化学水浴法,以硫代乙酰胺为硫源、氯化镉为镉源、尿素为缓冲剂,在酸性条件下制备了CdS薄膜。采用台阶仪、X射线衍射仪、扫描电镜和紫外/可见光分光光度计,研究了酸性条件下化学水浴沉积时间对硫化镉薄膜厚度、结构、形貌和光学特性的影响。结果表明,沉积所得的CdS薄膜为六角纤维锌矿结构。随着沉积时间的延长,薄膜厚度和晶粒尺寸随之增大,带隙随之减小。当沉积温度为80℃,沉积时间为30min时,CdS薄膜可见光波段平均透过率接近80%。     

Ferroelectric Thin Films and Multilayer Structures Based on Them

A brief review is presented of the results of recent research into ferroelectric films and their multilayer structures. The main attention is paid to theoretical calculation of the physical properties that characterize ferroelectric materials (electric polarization, phase transition temperature, dielectric response) in thick and thin films and their multilayer structures. Within the phenomenological theory it is shown that the main reason for a decrease in film symmetry is internal mechanical stress connected with the mismatch in lattice constants, difference in thermal expansion coefficients of the substrate and film, and also growth imperfections. These stresses lead to a change (decrease or increase) in the para-ferroelectric transition temperature that is actually observed in thick films. In thin films, where it is necessary to consider polarization gradients, a ferroelectric transition develops whose temperature depends on film thickness (thickness induced phase transition). The polarization and dielectric permittivity of films and their multilayer structures are calculated. It is demonstrated that permittivity becomes infinitely great close to the thickness induced phase transition temperature. The theory fits well with the recently observed huge dielectric permittivity and its temperature dependence in a multilayer structure of thin films of PbTiO₃ and Pb_0.72La_0.28TiO₃.