A photoconductor based on heavily Al-doped nano-ZnO thin film and its application to a chaos generator

Nano-ZnO thin film with heavy Al doping was deposited on Si substrate by RF magnetron sputtering, and a photoconductor was fabricated on the nano-ZnO thin film using Au as contact metal, producing with a metal–semiconductor–metal structure. The photoconductor was then applied to Chua's circuit through element replacement. Simulation results demonstrated that a triple-scroll optoelectronic chaotic attractor can be generated in the modified Chua's circuit.     

Selective Growth of Vertical-aligned ZnO Nanorod Arrays on Si Substrate by Catalyst-free Thermal Evaporation

By thermal evaporation of pure ZnO powders, high-density vertical-aligned ZnO nanorod arrays with diameter ranged in 80–250 nm were successfully synthesized on Si substrates covered with ZnO seed layers. It was revealed that the morphology, orientation, crystal, and optical quality of the ZnO nanorod arrays highly depend on the crystal quality of ZnO seed layers, which was confirmed by the characterizations of field-emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and photoluminescence measurements. For ZnO seed layer with wurtzite structure, the ZnO nanorods grew exactly normal to the substrate with perfect wurtzite structure, strong near-band-edge emission, and neglectable deep-level emission. The nanorods synthesized on the polycrystalline ZnO seed layer presented random orientation, wide diameter, and weak deep-level emission. This article provides a C-free and Au-free method for large-scale synthesis of vertical-aligned ZnO nanorod arrays by controlling the crystal quality of the seed layer.     

Preparation of ZnO nanorod by solvothermal reaction of zinc acetate in various alcohols

Solvothermal reaction of zinc acetate in various alcohols resulted in the formation of zinc oxide (ZnO) nanorods. The effects of reaction conditions on the product morphology as well as crystallization mechanism were investigated by using X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) techniques. It was found that average diameter and length of the nanorods increased with an increase in reaction temperature or the initial concentration of zinc acetate. On the contrary, the aspect ratio of the product depended upon type of alcohol used as the reaction medium. The aspect ratio of ZnO nanorods increased from 1.7 to 5.6 when the alcohol was changed from 1-butanol to 1-decanol. An investigation of the reaction mechanism suggested that the formation of ZnO nanorods was initiated from the esterification reaction between zinc acetate precursor and alcohol to form ZnO seeds.     

Influence of ZnO buffer layer thickness on the electrical and optical properties of indium zinc oxide thin films deposited on PET substrates

The influence of the ZnO buffer layer thickness on the electrical and optical properties of In₂O₃–10 wt.% ZnO and ZnO bilayers deposited on polyethylene terephthalate (PET) substrates by RF magnetron sputtering were investigated. The optimum ZnO buffer layer thickness was found to be 90 nm which gives the lowest electrical resistivity of the bilayer of IZO and ZnO deposited on the PET substrate. The surface roughness decreases and diffusion of moisture and gas is more efficiently restrained, which contributes to lower the resistivity of the bilayer as the ZnO buffer layer thickness is increased. On the other hand, the total resistivity of the bilayer increases as the ZnO buffer layer thickness is increased because the resistivity of ZnO is higher than that of IZO. Introduction of a ZnO buffer layer does not nearly affect the IZO/ZnO/PET sample.     

Influence of annealing atmosphere on the structure, resistivity and transmittance of InZnO thin films

Dependence of the electrical and optical properties of In₂O₃–10 wt% ZnO (IZO) thin films deposited on glass substrates by RF magnetron sputtering on the annealing atmosphere was investigated. The electrical resistivities of indium zinc oxide (IZO) thin films deposited on glass substrate can be effectively decreased by annealing in an N₂ + 10% H₂ atmosphere. Higher temperature (200 °C) annealing is more effective in decreasing the electrical resistivity than lower temperature (100 °C) annealing. The lowest resistivity of 6.2 × 10⁻⁴ Ω cm was obtained by annealing at 200 °C in an N₂ + 10% H₂ atmosphere. In contrast, the resistivity was increased by annealing in an oxygen atmosphere. The transmittance of IZO films is improved by annealing regardless of the annealing temperature.     

Boron and nitrogen co-doped ZnO thin films for opto-electronic applications

The transparent conductive oxides such as ZnO have been widely studied due to their potential applications. As a promising wide band gap semiconductor, ZnO thin films with various dopants are important in fabricating the photonic devices to meet the various needs. In this study, boron and nitrogen co-doped ZnO thin films were fabricated at different temperatures (100–600 °C) on sapphire (0 0 1) substrates using pulsed laser deposition technique. X-ray diffractometer, atomic force microscope, spectrophotometer and spectrometer were used to characterize the structural, morphological and optical properties of the thin films. Hall measurements were also carried out to identify the electrical properties of the thin films.     

CdS／ZnO复合光催化剂催化分解硫化氢制氢研究

采用溶胶-凝胶-沉淀的方法,制备出CdS／ZnO复合光催化剂,并通过XRD和UV—Vis漫反射光谱对催化剂进行了表征。考察了ZnO制备过程中胶溶剂种类、CdS物质的量百分含量（X）和焙烧温度（T）对CdS／ZnO复合光催化剂的性质与光催化分解硫化氢制氢性能的影响。实验结果表明：CdS／ZnO复合催化剂中,ZnO和CdS为六方晶系,UV—Vis吸收边有不同程度的红移。当以氨水为胶溶剂,T为400℃,x为50时,制备出的CdS／ZnO复合催化剂,其光催化分解硫化氢制氢速率最大,可达35mmol／g·h。     

复合催化剂催化D，L-丙交酯的合成实验研究

D,L-丙交酯（DLLA）是合成聚乳酸的关键中间体,其收率直接影响到聚乳酸的收率。采用氯化亚锡／氧化锌做为复合催化剂,研究合成丙交酯的反应条件,提高了丙交酯的收率。实验结果表明：当采用复合催化剂,氯化亚锡：氧化锌的质量比=4：1,其用量为乳酸质量的1％,在减压条件下（20kPa）,130—140℃脱水3．5h,馏出温度为220℃时,可使DLLA收率最大为36．0％。     

硬脂酸对纳米ZnO的有机表面修饰研究

利用硬脂酸对纳米ZnO进行有机表面修饰;采用红外光谱(IR)、热分析(TG-DTA)、透射电镜(TEM)、润湿性实验、分散性实验等手段对表面改性前后的纳米ZnO进行表征。红外光谱和TEM表明,在纳米ZnO表面包覆有硬脂酸的有机层;热分析显示,包覆量约为18.98%;润湿性实验及分散性实验表明,经硬脂酸改性的纳米ZnO的表面由亲水性变为亲油性。     

纳米ZnO/PP及ZnO/CaCO_3/PP复合材料的性能研究

纳米氧化锌(ZnO)与聚丙烯(PP)通过熔融共挤制得了ZnO/PP纳米复合材料.研究了ZnO/PP纳米复合材料的力学、流变学性能与纳米ZnO添加量之间的关系;同时制备了ZnO/CaCO3/PP三元纳米复合材料并对其进行了机械性能和制备成本分析.结果表明,ZnO/PP纳米复合材料的熔体质量流动速率较纯PP有较大程度的提高;纳米CaCO3的加入不但可以降低生产成本,而且可以显著改善体系的冲击韧性;材料的拉伸破坏属于韧性断裂过程.