均匀沉淀法制备纳米氧化锌实验研究

以尿素和硝酸锌为原料,以辛基苯酚聚氧乙烯(10)醚(OP-10)为表面活性剂,采用均匀沉淀法制备了纳米氧化锌.采用单因素实验和正交实验,系统的分析了锌离子浓度、反应物配比、反应温度、煅烧温度、煅烧时间对氧化锌粒径的影响.采用扫描电镜(SEM)、X射线衍射(XRD)对所制备的纳米氧化锌进行了表征.结果表明,在锌离子浓度为0.4 mol/L,反应物配比为4,反应温度为120C,煅烧温度为450℃,煅烧时间为2h时,所得氧化锌粒径最小,且分布均匀,其平均粒径为30 nm,晶型为六方晶系.     

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.     

基片温度对氧化铋薄膜光学性质的影响

在玻璃基片上直流磁控溅射沉积氧化铋薄膜,基片温度从室温增加到300℃并保持其它沉积条件一致,研究基片温度对薄膜光学性能的影响.样品的晶体结构、表面形貌和透射光谱分别用X射线衍射仪、原子力显微镜和分光光度计进行测量.结果表明,随着基片温度的增加,样品中Bi2O3的(120)衍射峰强度增强,表面颗粒直径逐渐减小;基片温度为250,300℃样品出现了Bi2O2.75的(006)衍射峰.采用拟合透射光谱数据的方法计算薄膜的折射率,消光系数及厚度,并求出光学带隙.随基片温度的增加,氧化铋薄膜的折射率减小,消光系数在10-2～10-1数量级,光学带隙在3.51～3.04 eV递减.     

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。     

单晶硅上电沉积Ni—W—P合金薄膜

在单晶硅上电沉积制备了具有不同组成和结构的Ｎｉ－Ｗ－Ｐ合金薄膜，研究了镀液组成，温度，ｐＨ值和电流密度等因素对镀层组成的影响，用Ｘ射线衍射法分析了薄膜的结构，结果表明，提高温度有利于钨的沉积，降低ｐＨ值有利于高磷薄膜的形成，随着合金中钨，磷含量的增加，晶粒尺寸逐渐减小，薄膜由晶态变为非晶态结构。     

纳米氧化锌的均匀沉淀法制备工艺研究

介绍了以醋酸锌与尿素为原料,添加表面活性剂,均匀沉淀法制备纳米氧化锌的新工艺.讨论了反应物浓度的配比、反应浓度、反应时间、表面活性剂对纳米氧化锌形成的影响.采用X射线衍射(XRD)、激光粒度分析仪、热分析、扫描电镜等方法对制备纳米氧化锌进行表征,结果表明:制得的氧化锌的平均粒径为52 nm,晶型为六方晶系.     

石墨烯掺杂氧化锡薄膜的结构与光学性能的研究

以SnCl₄·5H₂O和石墨烯为原料,采用溶胶-凝胶法在石英玻璃衬底上制备了SnO₂掺杂石墨烯的薄膜,研究了膜层厚度对SnO₂薄膜的结构与光学性能的影响.测试结果表明,石墨烯的掺入使氧化锡薄膜的晶体质量得到提高, 薄膜样品的光学带边往长波方向发生移动,即产生“红移”现象,随着石墨烯含量的增加,氧化锡薄膜光致发光强度表现为逐步淬灭的现象.      

钨的离子交换新工艺的发展

钨的离子交换新工艺是利用强碱性阴离子交换树脂对钨酸钠溶液中不同离子的吸附能力的差异。又应用对树脂亲和力较小的离子能显著增加其浓度并能将对树脂亲和力较大的离子置换下来的特性。达到分离杂质和提纯钨的目的。该新工艺经过加多年的不断改进和完善。已发展成为成熟的钨的离子交换新技术。     

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。     

基底温度对反应磁控溅射氮化铝薄膜的影响

采用反应磁控溅射法结合加热控温电源,在光学玻璃基底上制备氮化铝(AlN)薄膜,通过X射线衍射(XRD)技术对薄膜样品物相结构进行分析,利用纳米压痕仪测试薄膜样品的硬度及弹性模量,用椭圆偏振仪及光栅光谱仪测试了薄膜样品的光学性能,分析和研究了基底温度对AlN薄膜的结构及性能的影响.结果表明,用此方法获得的AlN薄膜呈晶态,属于六方晶系,温度对AlN(100)面衍射峰强度影响不大,但对(110)面衍射峰的影响较大,因而温度对AlN的择优取向有一定影响.AlN(100)峰半高宽随温度升高而减小,表明晶粒尺寸随温度升高有变大趋势.随沉积温度升高,薄膜硬度从150℃的8 GPa增加到350℃的10 GPa左右,随基底温度升高,薄膜的硬度增加.弹性模量随温度的变化趋势与硬度的基本一致.在可见光区域AlN薄膜透过率超过90％,基本属于透明膜.基底温度对薄膜折射率也有较明显影响,折射率大致随温度升高而增大,但由椭偏测试及透射谱线分析得到的厚度结果表明,随温度升高,AlN薄膜的沉积速率下降.     

A Study of Pb-Doping Effect on Structural,Optical, and Morphological Properties of ZnO Thin Films Deposited by Sol–Gel Spin Coating

In our study, undoped and lead (Pb)-doped ZnO thin films were deposited by sol–gel spin-coating technique and the structural, morphological, and optical properties of the films were investigated as a function of Pb doping which was changed from 0 to 4 at. pct with 1 at. pct step. The XRD results exhibited that the films had a hexagonal wurtzite structure with (002) preferential orientation in all dopant ratios. The grain size values of Pb-doped films were lower than that of undoped ZnO, but the increase in strain and dislocation density values were observed with Pb doping. Detailed optical analysis showed that the average transmittance of all films varied between about 90 and 99 pct and the absorption edge of undoped ZnO film shifted from longer wavelength to short wavelengths (blue shift) with Pb doping. The optical band gap and Urbach energy values of undoped ZnO increased from 3.283 eV and 63 meV to 3.331 eV and 88 meV with increasing Pb doping ratio. But steepness parameter values showed reversely variation with increasing Pb doping. The AFM images expressed that the films had homogenous nanoparticle distribution on the surface and particle size of ZnO decreased with Pb doping ratio. These results suggested that undoped and Pb-doped ZnO thin films could be used in many technological areas.     

Influence of Annealing on Microstructure and Photoluminescence Properties of Al-Doped ZnO Films

Effect of annealing temperature and time on the microstructure and photoluminescence (PL) properties of Al doped ZnO thin films deposited on Si (100) substrates by sol-gel method was investigated. An X-ray diffraction (XRD) was used to analyze the structural properties of the thin films. All the thin films have a preferential c-axis orientation, which are enhances in the annealing process. It is found from the PL measurement that near band edge (NBE) emission and deep-level (DL) emissions are observed in as-grown ZnO∶Al thin films. However, the intensity of DLE is much smaller than that of NBE. Enhancement of NBE is clearly observed after thermal annealing in air and the intensity of NBE increases with annealing temperature. Results also show that the PL spectrum is dependent not only on the processing temperature but also on the processing time. The DLE related defects can not be removed by annealing, and on the contrary, the annealing conditions actually favor their formation.     

Intrinsic Room-Temperature Ferromagnetic Properties of Ni-Doped ZnO Thin Films

We report on room temperature intrinsic ferromagnetism in Ni doped ZnO films grown on Si (100), c-sapphire, and r-sapphire substrates. Transmission electron microscopy (TEM) data ruled out precipitation of Ni. The microstructural dependence of coercivity pointed to an intrinsic origin of ferromagnetic behavior in Ni-doped ZnO. It was observed that doping with Ni did not significantly affect the electrical and optical properties of ZnO. Resistivity measurements down to 0.04 K (−272.96 °C) showed metallic conducting behavior in Ni-doped ZnO films, indicating the formation of a shallow donor band.     

Gd掺杂CdTe薄膜的结构和光学特性研究

用真空热蒸发法在玻璃衬底制备CdTe和Cd掺杂CdTe薄膜.研究热处理和Gd掺杂量对CdTe薄膜结构、光学特性的影响.结果表明,薄膜均为立方闪锌矿结构,Gd的掺入没有改变薄膜的晶体结构,但使薄膜的晶粒尺寸减小,晶格常数和晶胞体积略有增大,并使其择优取向由[220]晶向变为[111]晶向.掺Gd使薄膜在可见光范围透过率增强,但对光能隙影响不大.     

Effect of Cobalt Doping on Nanostructured CuO Thin Films

The growth of cobalt-doped nanostructured CuO thin films using the successive ionic layer adsorption and reaction (SILAR) method is presented. It is found that Co doping considerably influences the structural (X-ray diffraction (XRD)), morphological (finite-element–scanning electron microscopy (FESEM)), and optical (ultraviolet/visible (UV/vis.) and Raman) properties of the films. XRD experiments evidence that the crystallite size of the films decreased with increasing Co doping. FESEM images reveal that the grain size of the nanostructures decreased with increasing doping concentration. By UV/vis. analysis, it is found that Co doping has a decreasing effect on band gap energy. The broadening and downshift of the Raman peaks are mainly attributed to the quantum confinement effect of CuO nanostructures.     

Tm-doped ZnO nanorods as a TCO for PV applications

In photovoltaic(PV) devices, a transparent conducting oxide(TCO) film is used as a transparent electrode which permits sun rays to reach to the photoactive semiconducting layers and also to collect the photogenerated electrons. Due to their electrical and optical properties zinc oxide(ZnO) based thin films and nanostructures are considered as an abundant and safer option for TCOs. In this study, undoped and thulium(Tm)-doped ZnO nanorods(NRs) were produced on glass substrates via spin coating and hydrothermal methods. The ZnO samples were described by X-ray diffractometry(XRD). Morphological features of the ZnO samples were investigated with scanning electron microscopy(SEM). It is observed that the all ZnO samples have nanorod shape. The average rods diameter is between 75 and 100 nm. Also,the rods length is found to be between 0.96 and 1.62 μm. Electrical properties of the ZnO samples were performed via four probe method. The conductivity increases with measurement temperature and Tm doping. Optical spectra of the ZnO samples were measured in UV-Vis range and the band gap(E_g) is found to be 3.35 eV.     

Optical and Micro-Structural Properties of ZnO Thin Films Grown on Silicon Substrate by Pulsed Laser Deposition

ZnO thin films were deposited on n-Si (111) at various substrate temperatures and oxygen pressures by pulsed laser deposition (PLD) using a Nd∶YAG laser with the wavelength of 1064 nm. X-ray diffraction (XRD), photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the microstructure, optical property and morphology of the ZnO thin films. A comparatively optimal crystallized ZnO thin film was obtained at the substrate temperature of 600 ℃ in oxygen pressure of 50 mTorr. The intensity of the luminescence strongly depends on the stoichiometry of the film as well as the crystalline quality.     

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。     

Evaluation of Structural and Optical Properties of Mn-Doped ZnO Thin Films Synthesized by Sol-Gel Technique

Undoped ZnO and Mn-doped ZnO (MZO) films with 0.25, 0.50, and 0.75?mol pct were synthesized onto glass substrates by sol-gel spin-coating technique, and the effects of Mn on structural, morphologic, and optical properties were investigated. The XRD results indicate that the films have wurtzite structure with polycrystalline nature. However, the dominant peak was (002) diffraction peak for all samples; other diffraction peaks with less intensity such as (100), (101), (102), (110), (103), (112), and (004) were observed for the undoped ZnO. The lattice parameter values of MZO thin films were lower than that of the undoped ZnO. Plane stress values indicated that the films had the tensile stress. A decrease in the grain sizes was observed with the increasing Mn mole?percent. The optical transmission values were found to be 82?pct for the undoped ZnO and 80, 78, and 75?pct for the MZO with 0.25, 0.50, and 0.75?mol?pct, respectively, at the wavelength of 405?nm. The optical band gap values decreased from 3.287 to 3.270?eV, the surface roughness values increased from 58.13 to 60.67?nm, Urbach energy values increased??a 18.3-meV difference in Urbach energy was observed??and in addition, the steepness parameters decreased with increasing Mn content from 0 to 0.75?mol?pct.