H_2气氛退火处理对Nb掺杂TiO_2薄膜光电性能的影响

采用电子束沉积方法,以钛酸锶(SrTiO3)为衬底制备铌(Nb)掺杂TiO2薄膜并研究后续H2气氛退火处理对其薄膜样品光电性能的影响.结果发现H2气氛热退火处理能有效改善Nb掺杂TiO2薄膜的导电率,最佳电阻率达到5.46×10-3Ω·cm,在可见光范围内的透光率为60%—80%.导电性能的改善与H2气氛退火处理后多晶薄膜的晶粒尺寸变大和大量的氧空位形成及H原子掺杂有关.     

生长温度对Ga掺杂ZnO薄膜光电性能的影响

在不同衬底温度(室温~750 ℃)条件下,采用脉冲激光沉积(PLD)方法在石英玻璃和单晶硅(111)衬底上制备了Ga掺杂ZnO(GZO)薄膜。结果显示:衬底温度的变化导致衬底表面吸附原子扩散速率和脱附速率的不同,从而导致合成薄膜结晶质量的差异,衬底温度450 ℃时制备的GZO薄膜具有最好的结晶特性;GZO薄膜中载流子浓度随衬底温度升高而单调减小的现象与GZO薄膜中的本征缺陷密切相关,晶界散射强度的变化导致迁移率出现先增大后减小的趋势,衬底温度450 ℃时制备的GZO薄膜具有最小的电阻率~0.02 Ω·cm;随着衬底温度的升高,薄膜载流子浓度的单调减小导致了薄膜光学带隙变窄,所有合成样品的平均可见光透过率均达到85%以上。采用PLD方法制备GZO薄膜,衬底温度的改变可以对薄膜的光电性能起到调制作用。     

Ga-Ti共掺杂ZnO薄膜的制备及其光电性能

采用ZnO:Ga2O3:TiO2为靶材,在玻璃衬底上射频磁控溅射制备了多晶Ga-Ti共掺杂ZnO(GTZO)薄膜,通过XRD、四探针、透射光谱测试研究了生长温度对薄膜结构和光电性能的影响.结果表明:所制备的薄膜具有c轴择优取向,光学带隙均大于本征ZnO的禁带宽度.当生长温度为620K时GTZO薄膜的结晶质量最佳、电阻率最低、透射率最大、品质因数最高.     

Zr掺杂TiO_2薄膜的光学性能和光催化性能

为了研究TiO2禁带宽度和光吸收系数对其光催化性能的影响,利用电子束沉积方法在玻璃基底上制备了TiO2薄膜及Zr掺杂TiO2薄膜。采用拉曼光谱仪和分光光度计对膜的结构和吸收光谱进行了表征。研究结果表明:当退火温度为773K时,沉积得到的TiO2薄膜为锐钛矿结构薄膜;掺杂使TiO2禁带宽度变窄,吸收波长红移,在350~450nm附近光吸收系数增大,增强了TiO2的光催化活性。     

Co掺杂ZnO薄膜的结构和磁学性能

研究了用单束脉冲激光沉积法制备的Co掺杂ZnO薄膜的结构和磁学性能。XRD表征结果表明制备的薄膜是具有沿c轴择优取向的纤锌矿点阵结构。然而,进一步的高分辨电子显微镜结果显示整个样品上的晶体取向并不完全相同。很难说明形成了单晶。结果分析表明Co占据了部分Zn的格点,并对电子结构产生了影响。室温下观察到了磁滞回线,显示掺杂Co可以实现ZnO的磁性翻转,但磁性比较小。该薄膜与我们以前用双束脉冲激光沉积法制备的Co掺杂ZnO薄膜具有相似的性能,提示我们其内部的机制可能相似。     

PLD法制备钴掺杂的氧化锌薄膜及其生长形貌和光学性能

用脉冲激光沉积(PLD)方法,在蓝宝石(0001)衬底上,制备了高度c轴取向的Zn1-xCoxO(x=0,0.02,0.05,0.07,0.1)薄膜。X射线衍射(XRD)分析表明,当钴掺杂量≤10mol%时没有出现其他杂峰,即没有出现分相。XPS分析显示Co离子在薄膜中以+2价的形式存在。进一步验证Co2+离子进入ZnO的晶格,对掺钴浓度不同的样品进行了UV-Vis吸收光谱测量。从UV-Vis吸收光谱可以看出随着掺杂浓度的增加,带隙逐渐变窄,证明Co2+取代了Zn2+而进入了ZnO晶格中。从原子力显微镜(AFM)形貌表征可以看出,随着钴掺杂量的提高,ZnO薄膜的表面起伏度有所减小,而且生长晶粒细化,从生长动力学的角度对生长形貌的改善进行了解释。     

Cu掺杂SnO_2/TiO_2复合薄膜的制备及性能研究

制备Cu掺杂的纳米Sn O2/Ti O2溶胶,采用旋涂法在载玻片上镀膜,经干燥、煅烧制得Cu掺杂的Sn O2/Ti O2薄膜,通过对比实验探讨掺杂比例、条件、复合形式等对结构和性能的影响。采用XRD、SEM、EDS、UVVis等测试手段对样品进行表征,并以甲基橙为探针考察了其光催化降解性能。XRD测试结果显示薄膜的晶型为锐钛矿型,结晶度较高。SEM谱图显示薄膜表面无明显开裂,粒子分布均匀,粒径约为20 nm。EDS测试结果表明薄膜材料中含有Cu元素,谱形一致。UV-Vis吸收光谱表明Cu掺杂以及Sn O2/Ti O2的复合使得在近紫外区的光吸收比纯Ti O2明显增强。光催化实验表明Cu掺杂后使得Sn O2/Ti O2复合薄膜对甲基橙的光催化降解效率进一步提高,Sn O2/Ti O2复合薄膜的光催化活性在10%Cu掺杂时达到最高。     

钽掺杂氧化钨薄膜电致变色性能

为改善氧化钨电致变色薄膜的电化学循环稳定性,采用磁控溅射方法制备了钽掺杂的氧化钨电致变色薄膜。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、光谱椭偏仪(SE)、紫外-可见分光光度计、电化学工作站对薄膜的微观结构、光谱调制能力、着色效率、循环稳定性进行了表征和分析,研究了钽掺杂对氧化钨薄膜结构及电致变色性能的影响。结果表明,适量掺杂可以调节薄膜的微观结构,使薄膜中的裂纹减少,表面更为均匀;但当掺杂过度时,薄膜太过致密,甚至出现表面颗粒团聚凸起的现象,影响了薄膜的多孔性和均匀性,阻碍了离子在薄膜中的迁移和扩散;相对于未掺杂的氧化钨薄膜,适量钽掺杂的薄膜具有更宽的光谱调制范围和更高的着色效率,亦表现出良好的循环稳定性。     

PLD制备的Cu掺杂SnS薄膜的结构和光学特性

利用脉冲激光沉积(PLD)在玻璃衬底上制备了Cu掺杂SnS薄膜.靶材是由SnS和Cu₂S粉末混合压制而成(Cu和Sn的量比分别为0%、2.5%、5%、7.5%和10%).利用X射线衍射(XRD)、拉曼光谱仪(Raman)、原子力显微镜(AFM)、紫外-可见-近红外分光光度计(UV-Vis-NIR)、Keithley 4200-SCS半导体参数分析仪研究了Cu掺杂量对SnS薄膜的晶体结构、表面形貌、光学性质和电学性能的影响.结果表明:所制备的SnS薄膜样品沿(111)晶面择优取向生长, SnS :5%Cu薄膜的结晶质量最好且具有SnS特征拉曼峰.随着Cu掺杂量的增大, 平均颗粒尺寸逐渐增大.不同Cu掺杂量的薄膜在可见光范围内的吸收系数均为10⁵ cm^-1数 量级.SnS :5%Cu薄膜的禁带宽度E_g为2.23 eV, 光暗电导率比值为2.59.同时, 在玻璃衬底上制备了p-SnS :Cu/n-ZnS 异质结器件, 器件在暗态及光照的条件下均有良好的整流特性, 并具有较弱的光伏特性.     

应变增强Nb掺杂SrTiO3薄膜热电性能

高性能热电材料的发展有望帮助解决未来能源危机,且随着可穿戴器件的发展与应用,热电材料和器件除了要具备更高的热-电转化性能以外,还必须具有良好的柔性.将热电材料制成薄膜既可以为微型器件供电,也有潜力应用于柔性器件.本文使用脉冲激光沉积方法,在商用SrTiO₃ (STO)和La_0.3Sr_0.7Al_0.65Ta_0.35O₃ (LSAT)衬底上制备得到了不同厚度的高质量铌掺杂钛酸锶薄膜(Nb:STO),并对薄膜的表面形貌、结构以及热电性能进行表征与测试.结果显示,使用LSAT作为衬底可以对薄膜施加面内压应变,随着薄膜厚度的增大,应变逐渐释放并接近于块体Nb:STO.随着厚度的增大,薄膜的热电性能逐渐提升,在STO衬底上生长的208 nm厚样品的室温功率因子相比于52 nm样品提升了187%.此外, 144 nm厚度的Nb:STO/LSAT薄膜室温塞贝克系数达到了265.95 μV/K,这是由于衬底应变导致薄膜样品的能带变化.本工作表明通过应变工程调控铌掺杂钛酸锶薄...     

原子层沉积HfO2薄膜的激光损伤特性分析

以目前激光惯性约束聚变中应用最广泛的高折射率材料二氧化铪(HfO2)为研究对象,在熔石英基底上分别采用TEMAH和HfCl4前驱体制备了HfO2薄膜,沉积温度分别为100,200和300 ℃。采用椭偏仪和激光量热计对薄膜的光学性能进行了测量分析,采用X射线衍射仪(XRD)对薄膜的微结构进行了测量。最后在小口径激光阈值测量平台上按照1-on-1测量模式对薄膜的损伤阈值进行了测试,并采用扫描电子显微镜（SEM）对损伤形貌进行了分析。研究表明,用同一种前驱体源时,随着沉积温度升高,薄膜折射率增加,吸收增多,损伤阈值降低。在相同温度下,采用有机源制备的薄膜更容易在薄膜内部形成有机残留,导致薄膜吸收增加,损伤阈值降低。采用HfCl4作为前驱体源在100℃制备氧化铪薄膜时,损伤阈值能够达到31.8 J/cm2 (1064 nm,3 ns)。     

Oblique angle deposition of TiO2 thin films prepared by electron-beam evaporation

Optical, structural and photocatalytic properties of TiO₂ thin films obliquely deposited on quartz glass substrate using an electron-beam evaporation method were investigated. The photocatalytic activity of the films was evaluated by photodecomposition of methylene blue. An increase in incident deposition angle increased the porosity and surface roughness of the TiO₂ films. As a result, the photocatalytic activity was enhanced with incident deposition angle up to 60°. However, a further increase in incident deposition angle to 75° reduced the photocatalytic activity due to a lack of the crystalline phase.     

Substrate effects on the oxygen gas sensing properties of SnO2/TiO2 thin films

In this study, SnO₂/TiO₂ thin films are fabricated on SiO₂/Si and Corning glass 1737 substrates using a R.F. magnetron sputtering process. The gas sensing properties of these films under an oxygen atmosphere with and without UV irradiation are carefully examined. The surface structure, morphology, optical transmission characteristics, and chemical compositions of the films are analyzed by atomic force microscopy, scanning electron microscopy and PL spectrometry. It is found that the oxygen sensitivity of the films deposited on Corning glass 1737 substrates is significantly lower than that of the films grown on SiO₂/Si substrates. Therefore, the results suggest that SiO₂/Si is an appropriate substrate material for oxygen gas sensors fabricated using thin SnO₂/TiO₂ films.     

Damage performance of TiO2/SiO2 thin film components induced by a long-pulsed laser

In order to study the long-pulsed laser induced damage performance of optical thin films, damage experiments of TiO₂/SiO₂ films irradiated by a laser with 1 ms pulse duration and 1064 nm wavelength are performed. In the experiments, the damage threshold of the thin films is measured. The damages are observed to occur in isolated spots, which enlighten the inducement of the defects and impurities originated in the films. The threshold goes down when the laser spot size decreases. But there exists a minimum threshold, which cannot be further reduced by decreasing the laser spot size. Optical microscopy reveals a cone-shaped cavity in the film substrate. Changes of the damaged sizes in film components with laser fluence are also investigated. The results show that the damage efficiency increases with the laser fluence before the shielding effects start to act.     

Femtosecond pulsed laser deposition of nanostructured TiO2 films

Nanostructured deposits of TiO₂ were grown on Si (1 0 0) substrates by laser ablating a TiO₂ sintered target in vacuum or in oxygen using a Ti:sapphire laser delivering 80 fs pulses. The effect of the laser irradiation wavelength on the obtained nanostructures, was investigated using 800, 400 and 266 nm at different substrate temperatures and pressures of oxygen. The composition of the deposits was characterized using X-ray photoelectron spectroscopy (XPS) and the surface morphology was studied by environmental scanning electron microscopy (ESEM) and atomic force microscopy (AFM). Deposits are absent of microscopic droplets in all conditions explored. The best deposits, constituted by nanoparticles of an average diameter of 30 nm with a narrow size distribution, were obtained at the shorter laser wavelength of 266 nm under vacuum at substrate room temperature.     

Structural and optical properties of pulsed laser deposited SrBi2Nb2O9 thin films

SrBi₂Nb₂O₉ (SBN) thin films were prepared on fused quartz substrates at room temperature by pulsed laser deposition. The influence of deposition parameters such as target-to-substrate distance, oxygen pressure and annealing temperature on film crystallization behavior was investigated by X-ray diffraction. Results indicated that the films grown at the optimum processing conditions have polycrystalline structure with a single layered perovskite phase. The optical transmittance of the films prepared at various oxygen pressures was measured in the wavelength range 200–900 nm using UV–vis spectrophotometer. The results showed that there is a red shift in the optical absorption edge with a rise in the oxygen pressure. Refractive index as a function of wavelength and optical band gap of the films were determined from the optical transmittance spectra. The results indicated that the refractive index increases with increasing oxygen pressure at the same incident light wavelength, while the band gap reduces from 4.13 to 3.88 eV. It may be attributed to an increase in packing density and grain size, and decrease in oxygen defects.     

Electrochromic properties of spray deposited TiO2-doped WO3 thin films

TiO₂-doped WO₃ thin films were deposited onto fluorine-doped tin oxide coated conducting glass substrates using spray pyrolysis technique at 525 °C. The volume percentage of TiO₂ dopant was varied from 13% to 38%. The thin film samples were transparent, uniform and strongly adherent to the substrates. Electrochromical properties of TiO₂-doped WO₃ thin films were studied with the help of cyclic voltammetry (CV), chronoamperometry (CA) and chronocoulometry (CC) techniques. It has been found that TiO₂ doping in WO₃ enhances its electrochromic performance. Colouration efficiency becomes almost double and samples exhibit increasingly high reversibility with TiO₂ doping concentrations, in the studied range.     

Optical spectra of graded nanostructured TiO2 chiral sculptured thin films

The optical properties of graded chiral sculptured TiO₂ thin films in axial and non-axial excited states are calculated using the rigorous coupled wave analysis method (RCWA) in conjunction with the Bruggeman homogenization formalism. The filtering frequency and polarization selectivity of these graded nanostructured TiO₂ sculptured thin films showed dependence on both structural and deposition parameters. The results achieved are consistent with the experimental data [K. M. Krause and M. J. Bret, Adv. Funct. Mater. 18 (2008) 3111].     

利用脉冲激光沉积技术在双轴织构的Ni基带上外延CeO2薄膜

利用脉冲激光沉积技术在氢还原气氛下成功地在双轴织构的Ni基带上外延了高质量的CeO₂薄膜. x射线衍射θ—２θ扫描和ω扫描结果表明，CeO₂薄膜在Ni基带上呈c轴方向生长，存在很强的平面外织构；极图和φ扫描显示它具有良好的平面内织构. Ni基片上织构的CeO₂薄膜为进一步在其上外延高质量的YBa₂Cu₃O_7-x超导薄膜提供了很好的模板. 关键词： 双轴织构的Ni基带 2薄膜')" href="#">CeO₂薄膜 脉冲激光沉积