Nanobeads of zinc oxide with rhodamine B dye as a sensitizer for dye sensitized solar cell application

Cost effective, ruthenium metal free rhodamine B dye has been chemically adsorbed on ZnO films consisting of nanobeads to serve as a photo anode in dye sensitized solar cells. These ZnO films were chemically synthesized at room temperature (27 °C) on to fluorine doped tin oxide (FTO) coated glass substrates followed by annealing at 200 °C. These films consisting of inter connected nanobeads (20-40 nm) which are due to the agglomeration of very small size particles (3-5 nm) leading to high surface area. The film shows wurtzite structure having high crystallinity with optical direct band gap of 3.3 eV. Optical absorbance measurements for rhodamine B dye covered ZnO film revealed the good coverage in the visible region (460-590 nm) of the solar spectrum. With poly-iodide liquid as an electrolyte, device exhibits photon to electric energy conversion efficiency (η) of 1.26% under AM 1.5G illumination at 100 mW/cm².     

The role of pH and boron doping on the characteristics of sol gel derived ZnO films

Undoped and boron doped ZnO films (nominal volume B/Zn ratio = 1%, 3% and 5%) were deposited onto glass substrates by the sol gel method using spin coating technique. Zinc acetate dihydrate (ZnAc), 2-methoxyethanol and monoethanolamine (MEA) were used as a starting material, solvent and stabilizer, respectively. Trimethyl borate (TMB) was used as a dopant source. The pH value of the sol was adjusted with glacial acetic acid and ammonia and it changed from acid to base in nature. The effect of pH value and B dopant on the structural, morphological and optical properties of the films was investigated. The crystalline structure and orientation of the films were investigated using XRD study. The crystallite size of the films was determined. The XRD analyses showed that the undoped ZnO film crystallinity enhanced when pH of the precursor sol was increased from 5.05 to 7.00. Surface morphology was studied by a field emission scanning electron microscope (FESEM), and the effects of the doping concentration and pH values on the microstructure of the films were investigated. The optical band gap values on the surface morphology of the films were determined. The absorption edge shifted depending on the pH values and the B dopant.     

Elaboration and characterization of Al doped ZnO nanorod thin films annealed in hydrogen

ZnO thin films doped with Al concentrations of 1.0, 2.0, 3.0, 4.0, 5.0 at% were prepared by a sol-gel spin-coating method on glass substrates and respectively annealed at 550 °C for 2 h in hydrogen and air. The X-ray diffraction and selected-area electron diffraction results confirm that the Al doped ZnO thin films are of wurtzite hexagonal ZnO. The scanning electron microscope results indicate that the Al doped ZnO nanorod thin films can be got by annealing in hydrogen rather than in air. The optical properties reveal that the Al doped ZnO thin films have obviously enhanced transmittance in the visible region. The electrical properties show that the resistivity of 1.0 at% Al doped ZnO thin films has been remarkably reduced from 0.73 Ω m by annealing in air to 3.2 × 10⁻⁵ Ω m by annealing in hydrogen. It is originated that the Al doped ZnO nanorod thin films annealed in hydrogen increased in electron concentration and mobility due to the elimination of adsorbed oxygen species, and multicoordinated hydrogen.     

Effect of ammonia solution on properties of sprayed ZnO thin films consisting of nano-pyramids

Hexagonal wurtzite zinc oxide (ZnO) thin films were deposited at substrate temperatures from 300 to 500 °C with surfactant of ammonia solution. The effect of ammonia on the structural, surface morphology, compositional, optical and electrical properties of ZnO thin films was studied. X-ray diffraction shows that the all films are polycrystalline in nature and have a hexagonal wurtzite structure with a high preferential orientation (002) plane for ammonia solution. High-resolution SEM studies reveal the formation of ZnO films consisting of nano-pyramids with uniformly distributed grains over the entire surface of the substrates. Photoluminescence studies indicate the presence of two emission peaks: (a) a sharp ultra-violet near band edge ～392 nm, (b) a sharp visible deep-level green emission peak ～564 nm. The optical properties show that the direct band gap energy values increase with increasing substrate temperatures.     

Influence of iron doping on morphological,structural and optical properties of zinc oxide thin films prepared by dip-coating method

Undoped zinc oxide and iron-doped zinc oxide thin films have been deposited by the sol-geldipcoating method. The Fe/Zn nominal volume ratio was 5% in the solution. The effects of Fe incorporation on morphological, structural, and optical properties of ZnO films were investigated. The scanning electron microscopy measurements showed that the surface morphology of the prepared thin films was affected by Fe doping. The X-ray diffraction patterns of the thin films showed that doped incorporation leads to substantial changes in the structural characteristics of ZnO thin films. The optical absorption measurements indicated a band gap in the range of 3.31 to 3.19 eV. The X-ray photoelectron spectroscopy demonstrated that Fe is incorporated in the ZnO matrix with 6.5 atomic percent (at %). The energy dispersive spectroscopy studies indicated the formation of ZnO with high efficiency.     

Properties of doped ZnO transparent conductive thin films deposited by RF magnetron sputtering using a series of high quality ceramic targets

To obtain high transmittance and low resistivity ZnO transparent conductive thin films,a series of ZnO ceramic targets (ZnOAl,ZnO(Al,Dy),ZnO(Al,Gd),ZnO(Al,Zr),ZnO(Al,Nb),and ZnO(Al,W)) were fabricated and used to deposit thin films onto glass substrates by radio frequency (RF) magnetron sputtering.X-ray diffraction (XRD) analysis shows that the films are polyerystalline fitting well with hexagonal wurtzite structure and have a preferred orientation of the (002) plane.The transmittance of above 86% as well as the lowest resistivity of 8.43 x 10-3 Ω·cm was obtained.     

Preliminary Study on Electrical and Optical Properties of ZnO Film Grown by MOCVD

1 ＩｎｔｒｏｄｕｃｔｉｏｎＺｎＯｉｓａｗｉｄｅ ｇａｐ ( 3.2ｅＶａｔｒｏｏｍｔｅｍｐｅｒａｔｕｒｅ)ｓｅｍｉｃｏｎｄｕｃｔｏｒｍａｔｅｒｉａｌｈａｖｉｎｇｔｈｅｗｕｒｔｚｉｔｅｓｔｒｕｃｔｕｒｅｗｉｔｈｄｉｒｅｃｔｅｎｅｒｇｙｂａｎｄ .Ｉｔｈａｓｂｅｅｎｃｏｎｓｉｄｅｒｅｄａｓａｐｒｏｍｉｓ ｉｎｇｍａｔｅｒｉａｌｆｏｒｏｐｔｏｅｌｅｃｔｒｏｎｉｃｄｅｖｉｃｅｓｉｎｔｈｅｎｅａｒｕｌｔｒａｖｉｏｌｅｔ(ＵＶ)ａｎｄｂｌｕｅｓｐｅｃ ｔｒａ .ＡｎｉｎｔｅｒｅｓｔｉｎｇｆｅａｔｕｒｅｏｆＺｎＯｉｓｉｔｓｌ…     

溶胶-凝胶法制备Y2O3掺杂ZnO压敏薄膜及其电性能（英文）

研究溶胶-凝胶法制备不同浓度Y2O3掺杂对ZnO-Bi2O3压敏薄膜微观结构和电性能的影响。研究结果表明:Y2O3掺杂ZnO薄膜在750°C空气气氛下退火1h,ZnO薄膜的特征峰与ZnO的六方纤锌矿结构相匹配;ZnO晶粒直径随着掺杂量的增加而减小,Y2O3稀土掺杂氧化锌晶粒细化;薄膜厚度均匀且每一层厚度约80nm。研究结果还表明:当Y3+掺杂浓度为0.2%(摩尔分数)时,ZnO薄膜的非线性伏安特性最好,其漏电流为0.46mA,电位梯度为110V/mm,非线性系数为3.1。     

Zn靶与掺铝ZnO靶共溅射制备ZnO:Al薄膜及其性能

采用Zn靶和ZnO(掺2%Al2O3(质量分数))陶瓷靶在玻璃衬底上共溅射沉积Al掺杂ZnO薄膜,即ZnO:Al透明导电薄膜,研究Zn靶溅射功率(0～90 W)和衬底温度(室温、100℃和200℃)对薄膜结构、形貌、光学和电学性能的影响。结果表明:按双靶共溅射工艺制备的ZnO:Al薄膜的晶体结构均为六角纤锌矿结构,且随着Zn靶溅射功率的增加,薄膜的结晶质量呈现出先改善后变差的规律,薄膜中的载流子浓度逐渐升高,电阻率逐渐降低,而薄膜的光学性能受其影响不大;随着衬底温度的升高,薄膜的结晶性能得到改善,薄膜的可见光透过率增强,电阻率降低。     

Spray deposited superhydrophobic ZnO coatings via seed assisted growth

Superhydrophobic zinc oxide (ZnO) coatings were synthesized by a simple and cost-effective spray pyrolysis technique (SPT) via seed assisted growth onto the glass substrates at 723 K from an aqueous zinc acetate precursor solution. Initially, the ZnO seeds were synthesized from an aqueous 0.4 M zinc acetate solution onto the glass substrates at 723 K. For the seed assisted growth of ZnO, the solution concentrations (0.1 M to 0.4 M) were used and its effect on structural, morphological, optical and wettability properties of ZnO thin films was investigated. The synthesized films were found to be polycrystalline, with preferential growth along c-axis. Scanning electron microscopy (SEM) images show the uniform distribution of spherical grains of about 60-80 nm grain size. After seed assisted growth, film surface becomes very rough. The films were specular and transmittance of thin films decreases as the concentration of the precursor solution increases. The optical absorption spectrum shows a sharp absorption band-edge at 381 nm, corresponding to optical gap energy (Eg) of 3.25 eV. All samples are superhydrophobic in nature. The Zn4 sample shows the superhydrophobicity with highest value of the contact angle (CA) i.e. 165°. Such a superhydrophobic coatings can be useful in the anti-snow, anti-fog and self cleaning surfaces.     

Sol–gel synthesis of Y2O3-doped ZnO thin films varistors and their electrical properties

Y₂O₃-doped ZnO–Bi₂O₃ thin films were fabricated on silicon substrates by sol–gel process and annealed in air at 750 °C for 1 h. Microstructure and electrical properties of ZnO thin films were investigated. XRD analysis shows that all peaks of ZnO thin films are well matched with hexagonal wurtzite structure of ZnO. SEM results present that the ZnO grain size decreases with the increase of dopant concentration, which means that rare earth doped can refine the grain size. The thickness of each layer is uniform and the value of thickness is about 80 nm. The nonlinear V–I characteristics with the leakage current of 0.46 μA, the threshold field of 110 V/mm and the nonlinear coefficient of 3.1 could be achieved when the films contain 0.2% (mole fraction) yttrium ion.     

水热法制备高定向掺铝氧化锌纳米棒阵列

为了制备高定向光电性能优异的掺铝氧化锌(ZAO)纳米棒阵列,采用溶胶-凝胶法在玻璃基片上制备掺铝氧化锌薄膜,以ZAO薄膜为种子层,通过控制掺铝量、稳定荆等工艺参数,采用水热法制备出了高定向ZAO纳米棒阵列.实验表明,铝掺杂量为2%,直径在50nm左右的ZAO纳米棒阵列薄膜具有最好的光致发光性能,表面活性剂可以促进ZAO纳米结构的棒状生长,形成高定向ZAO纳米棒阵列.     

Properties of Ni doped and Ni-Ga co-doped ZnO thin films prepared by pulsed laser deposition

ZnNiO and Zn(Ni,Ga)O thin films were prepared on glass substrates by pulsed laser deposition. The obtained films are of good crystal quality and have smooth surfaces, which have a hexagonal wurtzite ZnO structure with a highly c-axis orientation without any Ga or Ni related phases. Hall-effect measurements showed that the ZnNiO film is n-type, in which the carrier concentration would be greatly enhanced by the addition of Ga. Room temperature ferromagnetism is observed for the ZnNiO and Zn(Ni,Ga)O films. The addition of Ga into the ZnNiO films increases the electron concentration but weakens the room temperature ferromagnetism.     

Eu掺杂ZnO薄膜与Si(100)衬底间扩散过程分析

利用雾化热解工艺,在Si(100)衬底上制备了Eu掺杂的ZnO薄膜,通过N2的作用,将前驱体溶液输送到衬底表面,同时为实现ZnO的晶化,衬底温度保持在350℃.通过RBS分析了薄膜和衬底之间的原子分布,结果显示了ZnO薄膜与Si衬底之间存在过渡层.对RBS数据的分析表明该过渡层的形成是由于Si向ZnO层中的扩散,表明Si向氧化物中的扩散是不能忽略的,即使在350℃的低温下.同时,作者利用Fick扩散方程对Si向Eu3 掺杂ZnO薄膜的扩散行为进行了分析,结果表明掺杂离子Eu3 具有阻止Si扩散的能力,其原因可能与Eu3 离子在晶界上的偏析有关.     

In doped ZnO thin films

ZnO thin films were deposited by ultrasonic spray technique, zinc acetate was used as starting solution with a molarity of 0.1 M. A set of indium (In) doped ZnO (between 2 and 8 wt%) thin films were grown on glass substrate at 350 °C. The present work is focused on the influence of the doping level on the structural, optical and electrical films properties. Optical film characterization was carried by using UV-visible transmission spectroscopy, the optical gap was deduced from absorption. From X ray diffraction (XRD) analysis, we have deduced that ZnO films are formed with nanocrystalline structure with preferential (0 0 2) orientation. The grain size is increased with In doping from 28 to 37 nm. Electrical characterization was achieved using two-probes coplanar structure, the measured conductivity varies from 2.3 to 5.9 Ω cm⁻¹ when increasing the doping level. However the optical gap is reduced from 3.4 to 3.1 eV.     

Room temperature ferromagnetism of Si-doped ZnO thin films prepared by sol–gel method

Pure ZnO and Si-doped ZnO thin films were deposited on quartz substrate by using sol-gel spin coating process. X-ray diffraction analysis shows that all the thin films have hexagonal wurtzite structure and preferred c-axis orientation. Si-doped ZnO films show room temperature ferromagnetism (RTFM) and reach the maximum saturation magnetization value of 1.54 kAm-1 at 3% Siconcentration. RTFM of Si-doped ZnO decreases with the increasing annealing temperature because of the formation of SiO 2 . Photoluminescence measurements suggest that the RTFM in Si-doped ZnO can be attributed to the defect complex related to zinc vacancies V Zn and oxygen interstitials Oi .     

Properties of multilayer gallium and aluminum doped ZnO(GZO/AZO) transparent thin films deposited by pulsed laser deposition process

Multilayer gallium and aluminum doped ZnO (GZO/AZO) films were fabricated by alternative deposition of Ga-doped zinc oxide(GZO) and Al-doped zinc oxide(AZO) thin film by using pulsed laser deposition(PLD) process. The electrical and optical properties of these GZO/AZO thin films were investigated and compared with those of GZO and AZO thin films. The GZO/AZO (1:1) thin film deposited at 400 °C shows the electrical resistivity of 4.18×10^?4 ωcm, an electron concentration of 7.5×10²⁰/cm³, and carrier mobility of 25.4 cm²/(V·s). The optical transmittances of GZO/AZO thin films are over 85%. The optical band gap energy of GZO/AZO thin films linearly decreases with increasing the Al ratio.     

电气石衬底温度对ZnO薄膜的结晶特征和光学特性的影响

利用超声雾化热解技术 (USP) 在不同温度的电气石和玻璃衬底上生长ZnO纳米片状薄膜。结构研究表明晶体为六方纤锌矿多晶结构。衬底温度越高,Raman特征峰越强,XRD结果给出（002）优势定向越明显,晶体结晶性能越好,晶粒尺寸越大。SEM图像显示片状ZnO晶体沿平行衬底方向叠加形成花状晶柱的微观形貌,沉积温度越高,晶柱宽度越大。UV-Vis表明电气石衬底上ZnO吸收峰强度高于玻璃衬底,最大吸收峰位置发生红移,高温下移动更大。     

Experimental Investigation of Spray-Deposited Fe-Doped ZnO Nanoparticle Thin Films: Structural, Microstructural, and Optical Properties

Structural, microstructural, and optical properties of the undoped and Fe-doped zinc oxide (ZnO) thin films grown by spray pyrolysis technique using zinc nitrate as a host precursor have been reported here. X-ray diffraction spectra confirm that all the films have stable wurtzite structure and the effects of Fe dopants on the diffraction patterns have been found to be in agreement with the Vegard’s law. Scanning electron microscopy results show good uniformity and dense surface having spherical-shaped grains. Energy dispersive x-ray analyses with elemental mapping of the Fe-doped films show that the Fe dopants are incorporated homogeneously into the ZnO film matrix. The x-ray photoelectron spectroscopy spectra confirm the presence of 3+ oxidation state of Fe in the doped films. Atomic force microscopy analyses clearly show that the average surface roughness and the grain size decrease with the addition of Fe dopants. Optical studies reveal that the optical band gap value decreases on Fe doping. The 1 at.% Fe-doped film shows normal dispersion for the wavelength range 450-700 nm. The PL spectra of the films show a strong ultraviolet emission centered at ~388 nm in the case of 1 at.% Fe-doped film. A slow photo current response in the films has been observed in the transient photoconductivity measurement.     

The wide band gap of highly oriented nanocrystalline Al doped ZnO thin films from sol–gel dip coating

Undoped and Al doped ZnO thin films were prepared on glass substrate by sol–gel dip coating from PVP-modified zinc acetate dihydrate and aluminium chloride hexahydrate solutions. The XRD patterns of all thin films indexed a highly preferential orientation along c-axis. The AFM images showed the average grain size of undoped ZnO thin film was about 101 nm whereas the smallest average grain size at 8 mol% Al was about 49 nm. The values of direct optical band gap of thin films varied in the range of 3.70–3.87 eV.