ZnO/Ag/ZnO多层结构薄膜的光电性质

通过磁控溅射方法生长了不同银层厚度的ZnO/Ag/ZnO多层结构的薄膜,并对其形貌、光吸收谱、光致发光和光响应特性进行了比较研究.结果表明ZnO薄膜中银薄层的加入使得光致发光的强度增强.银层厚度为6 nm样品制成的器件在350 nm处的光响应度为0.06 A/W,相对于ZnO薄膜提高了一个数量级.而当银层厚度达到15 ...     

Structural and optical properties of monodispersed ZnS/CdS/ZnO and ZnO/ZnS/CdS nanoparticles

Excellent luminescence properties of ZnS/CdS/ZnO and ZnO/ZnS/CdS nanocrystallites synthesized through a simple chemical method at room temperature are reported. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), UV–visible absorption and photoluminescence techniques were used to characterize the undoped ZnS, CdS and ZnO and the novel ZnS/CdS/ZnO and ZnO/ZnS/CdS nanoparticles. The optical properties of ZnS/CdS/ZnO and ZnO/ZnS/CdS nanoparticles reflect a combinational effect of the photoluminescent properties of ZnS, CdS and ZnO.     

退火对ZnO薄膜晶体结构和ZnO/p-Si异质结光电性质的影响

采用脉冲激光沉积方法在p-Si(100)衬底卜牛长ZnO薄膜,分别在500℃、600℃和700℃下真空退火,采用X射线衍射仪研究了退火对ZnO薄膜品体结构的影响,并测量了ZnO的面电阻和ZnO/p-Si异质结的、I-V特性曲线.研究表明,随着退火温度的升高,ZnO的(002)衍射峰强度逐渐增大,半峰全宽不断减小,同时薄膜内应力减小,ZnO晶粒尺寸变大.表明高温退火有助于ZnO薄膜结晶质量的提高.在没有光照的条件下,异质结的漏电流随退火温度的增加而增大;用650 nm光照射样品时,600℃退火的样品表现出最明显的光电效应,而过高的退火温度会破坏ZnO/p-Si异质结的界面结构,使其光电流变小.所以,要得到性能良好的光电器件,应选取适当的退火温度.     

磁控溅射制备本征ZnO/Ag/ZnO透明导电薄膜的性质研究

室温下采用射频磁控溅射氧化锌（ZnO）粉末靶、银（Ag）靶,在玻璃衬底上制备ZnO/Ag/ZnO透明导电薄膜。首先,ZnO厚度为30 nm时,改变Ag厚度制备3层透明导电薄膜,研究Ag层厚度及膜层间配比对光电性能的影响;其次,按ZnO∶Ag厚度比为30∶11比例制备不同厚度的3层透明导电薄膜,研究多层厚度对薄膜光电性能的影响。结果表明：Ag厚度为8 nm及11 nm的ZnO/Ag/ZnO表面相对平整,结晶程度较好,在可见光范围内最高透过率达到90%及86%,并且方块电阻为6 Ω/□及3.20 Ω/□,具有优良的光电性;当按配比制备ZnO/Ag/ZnO 3层膜时,增加ZnO厚度对Ag层的增透作用反而减弱,同时增加Ag层厚度也会降低3层薄膜的整体光学性。     

ZnO/Ag/ZnO multilayer transparent electrode for highly-efficient ITO-Free polymer solar cells

Ultrathin metal film (UTMF) with a ZnO/Ag/ZnO hybrid structure was used as transparent electrode in a high-efficiency bulk heterojunction system for the fabrication of ITO-free polymer solar cells. The performance of the devices was carefully tuned through optical simulation using transfer matrix method by varying the thickness of ZnO seed layer and thin absorber layer. By employing appropriate device architecture, polymer solar cells fabricated using this UTMF-based electrode show efficiency as high as 9.49%, which is slightly higher compared to that of ITO-based device. From good agreement between the external quantum efficiency and optical modeling, it was found that the optimized microcavity configuration formed in UTMF-based device can greatly enhance the absorbance of the BHJ layer at longer wavelength as well as the favored exciton distribution for better charge transport and collection.     

Resonant Raman scattering of ZnS,ZnO, and ZnS/ZnO core/shell quantum dots

Resonant Raman scattering by optical phonon modes as well as their overtones was investigated in ZnS and ZnO quantum dots grown by the Langmuir–Blodgett technique. The in situ formation of ZnS/ZnO core/shell quantum dots was monitored by Raman spectroscopy during laser illumination.     

ZnO/Ag/ZnO multilayer films for the application of a very low resistance transparent electrode

Transparent conductive ZnO/Ag/ZnO multilayer electrodes having much lower electrical resistance than the widely used transparent electrodes were prepared by simultaneous RF magnetron sputtering of ZnO and DC magnetron sputtering of Ag. An Ag film with different thickness was used as intermediate metallic layers. The optimum thickness of Ag thin films was determined to be 6 nm for high optical transmittance and good electrical conductivity. With about 20-25 nm thick ZnO films, the multilayer showed high optical transmittance in the visible range of the spectrum and had color neutrality. The electrical and optical properties of the multilayers were changed mainly by Ag film properties. A high quality transparent electrode, having sheet resistance as low as 3 ohm/sq and high transmittance of 90% at 580 nm, was obtained and could be reproduced by controlling the preparation parameter properly. The above property is suitable as transparent electrode for dye sensitized solar cells (DSSC).     

Thermo-mechanical performance of PVC/ZnO nanocomposites

The present paper deals with the study of thermo-mechanical performance of PVC/ZnO nanocomposites. The samples have been prepared by solution casting technique with different (0, 2, 4, 6 and 8) wt. % of ZnO nanoparticles in poly (vinyl chloride) (PVC) matrix and structurally characterized through scanning electron microscopy. In thermo-mechanical analysis, dynamic mechanical analyzer gives the information about storage modulus and phase transition temperature (T_g). From these viscosities, profile at elevated temperature and activation energy of phase transition can be evaluated. This study reveals that dispersion of nano-ZnO significantly altered the thermo-mechanical properties of neat PVC but the effect is composition-dependent.     

ZnO/P-Si异质结的光电特性研究

利用脉冲激光沉积方法在P-Si(100)衬底上生长ZnO薄膜,制备ZnO/P-Si异质结,研究衬底温度对异质结光电特性的影响.结果表明,在400℃,500℃,550℃和600℃下生长ZnO制备的异质结都有一定的整流特性,反向暗电流随着衬底温度的升高略有增加,在550℃下制备的样品具有最明显的光电效应.ZnO/P-Si异质结对可见光和紫外光呈现出不同的响应性.在可见光照射下,光电流随反向偏压急剧增大,偏压增大到某一值时,光电流增速变小,而在紫外光下,光电流有逐渐增大的趋势.根据ZnO的透射谱认为,可见光和紫外光是异质结不同的耗尽区诱导电子-空穴对产生光电流的.     

Microwave-assisted synthesis of CuO/ZnO and CuO/ZnO/Al2O3 precursors using urea hydrolysis

Binary CuO/ZnO and ternary CuO/ZnO/Al₂O₃ catalysts have been rapidly synthesized in a multimode microwave oven by the homogeneous precipitation of aurichalcite and hydrotalcite-like precursors using urea hydrolysis. For purposes of comparison, the same catalysts were prepared under conventional heating. The corresponding metal nitrates were mixed with various amounts of urea to yield different urea/(ΣM⁺) molar ratios. The precipitation proceeded stepwise, copper being the first metal to be hydrolyzed. It was found that the higher the urea content, the higher the alkalinization of the solution, an effect which favored the precipitation of Zn (II) (the most pH dependent metal), and in turn, the synthesis of aurichalcite and hydrotalcite-like precursors.Microwave-synthesized catalysts presented similar characteristics to those obtained under conventional heating, but in considerably reduced aging times. Microwave radiation proved to be more efficient than conventional heating under harsh conditions of precipitation, i.e., lower molar ratios of urea with respect to the metal cations in the solution.     

Photochemical synthesis of ZnO/Ag nanocomposites

Composite ZnO/Ag nanoparticles have been formed via the photocatalytic reduction of silver nitrate over the ZnO nanocrystals, their optical, electrophysical and photochemical properties have been investigated. Mie theory has been applied to analyze the structure of the absorption spectra of ZnO/Ag nanocomposite. The irradiation effects upon the optical properties of ZnO/Ag nanostructure have been investigated. It has been found that the irradiation of ZnO/Ag nanoparticles results in electrons accumulation by both the semiconductor and the metallic components of the nanocomposite. It has been found that silver nitrate can be photochemically deposited onto the surface of ZnO nanoparticles under the illumination with the visible light in the presence of the sensitizer – methylene blue. Kinetics of the sensitized Ag(I) photoredution has been studied. It has been concluded that the key stage of this process is the electron injection from singlet-excited methylene blue molecule into ZnO nanoparticle.     

Electrical behaviors of ZnO/graphene/Si and ZnO/graphene/PS composite structures obtained by spraying different volumes of graphene solution

In this paper, a novel ZnO/graphene/porous silicon hybrid device is fabricated and its electrical behaviors are studied along with a ZnO/graphene/silicon device. Graphene (G) is prepared by exfoliation of graphite foil in aqueous solution of inorganic salt. Porous silicon (PS) is fabricated by electrochemical etching of p-type silicon (Si). Graphene is deposited on the surface of Si and PS substrates by thermal spray pyrolysis method. ZnO rods are grown on the samples by using catalyst-free chemical vapor transport and condensation method. The current–voltage relationships of ZnO/G/Si and ZnO/G/PS devices are studied under different volumes of graphene solution. The results reveal the distinctive features of the I–V characteristics of the two devices for different volumes of graphene solution under room light as well as UV illumination.     

Field emission characteristics study for ZnO/Ag and ZnO/CNTs composites produced by DC electrophoresis

A simple controllable method is reported for the coating of ZnO nanowires with Ag nanoparticles and ZnO/carbon nanotubes (CNTs) composite. It has been achieved through DC electrophoresis AgNO₃ electrolyte and CNTs in the presence of isopropanol dispersion of ZnO nanowires. In the present work, the influence of Ag nanoparticles and CNTs on the field emission properties of the composite materials is studied. The results of this research demonstrate a remarkable enhancement of field emission current of ZnO nanowires in case of CNTs mixture and Ag nanoparticles coating.     

用卢瑟福背散射/沟道技术研究ZnO/Zn0.9 Mg0.1 O/ZnO异质结的弹性应变

利用卢瑟福背散射/沟道技术对射频等离子体辅助分子束外延法生长在蓝宝石衬底上的ZnO/Zn0.9Mg0.1O/ZnO异质结进行了组分分析,并得到了异质结弹性应变随深度的变化,应变由界面向表面逐渐释放,并由负变正,且在ZnO与Zn0.9Mg0.1O界面处轻微增大.负的应变是由于ZnO与衬底的晶格失配和热失配,而逐渐变为正值是Zn0.9Mg0.1O与ZnO的晶格常数差异及弹性应变的逐渐释放所致.     

用卢瑟福背散射/沟道技术研究ZnO/Zn0.9Mg0.1O/ZnO异质结的弹性应变

利用卢瑟福背散射/沟道技术对射频等离子体辅助分子束外延法生长在蓝宝石衬底上的ZnO/Zn_0.9Mg_0.1O/ZnO异质结进行了组分分析，并得到了异质结弹性应变随深度的变化，应变由界面向表面逐渐释放，并由负变正，且在ZnO与Zn_0.9Mg_0.1O界面处轻微增大.负的应变是由于ZnO与衬底的晶格失配和热失配，而逐渐变为正值是Zn_0.9Mg_0.1O与ZnO的晶格常数差异及弹性应变的 关键词： 异质结 卢瑟福背散射/沟道 弹性应变 ZnMgO     

Preparation and characterization of the ZnO:Al/Fe65Co35/ZnO:Al multifunctional films

The ferromagnetic transparent conducting film is a multifunctional film which has high visible transmittance, low resistivity and room-temperature ferromagnetism, simultaneously. In this article, ferromagnetic transparent conducting ZnO:Al/Fe₆₅Co₃₅/ZnO:Al multilayer films were fabricated by inserting a middle magnetic Fe₆₅Co₃₅ layer into aluminum-doped zinc oxide (ZnO:Al) matrix using a magnetron sputtering apparatus at substrate temperature ranging from room temperature (RT) to 400^∘C. The total film thickness was about 400 nm and the middle Fe₆₅Co₃₅ alloy layer was 4 nm. The influences of substrate temperature (T _s ) on the structural, electrical, optical and magnetic properties of the multilayer films were systemically investigated. The results showed that the microstructure and performance of the composite multilayer films strongly depended on the substrate temperature. The present results also showed that the inserted middle Fe₆₅Co₃₅ alloy thin layer played an important role in providing the RT ferromagnetism and decreasing the resistivity of the multilayer films. Therefore, it is possible to obtain a multifunctional film material with the combination of good optical transparency, high electrical conductivity and RT ferromagnetism.     

Au层退火温度对ZnO/Au/ZnO多层膜的结构、光学及电学性质的影响

采用金属有机化学气相沉积(MOCVD)技术在蓝宝石衬底上制备出晶体质量较好的透明导电的ZnO/Au/ZnO(ZAZ)多层膜,其中,Au夹层是通过射频磁控溅射的方法获得。通过对Au夹层进行不同温度的退火处理,研究了Au层退火温度对ZAZ多层膜的结构特性、电学性能和光学特性的影响。利用原子力显微镜(AFM)、扫描电子显微镜(SEM)、X射线衍射(XRD)仪、霍尔效应测试和透射谱分析等测试手段对ZAZ多层膜的性质进行了分析。测试结果表明,在200 ℃下对Au夹层进行快速退火处理,多层膜的结构、电学和光学性质达到最优,表面等离子体效应也更明显。其中,XRD(002)衍射峰的半高宽为0.14°,电阻率为2.7×10^-3 Ω·cm,载流子浓度为1.07×10²⁰ cm^-3,可见光区平均透过率为75.3%。