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.     

Fabrication and structure characterization of ITO transparent conducting film by sol-gel technique

Using In（NO3）3·5H2O and acetylacetone as raw materials and anhydrous SnCl4 as dopant, the transparent conducting indium tin oxide（ITO） films were prepared by sol-gel and dip-coating technique. The phase transformation, structure properties and physical properties （sheet resistance and transmittance） of the films were investigated by DTA-TG, XRD, SEM, four-probe method and UV-Vis spectrometry. The results indicate that it is feasible to fabricate 1TO films on the quartz substrates by sol-gel technique, and the ITO films are formed by accumulating of particles with the size of several decades of nanometers. The prepared ITO film has cubic bixbyite structure, and （111） is its preferred plane. After five-times dip-coating, the 1TO film has a thickness less than 150 nm, a sheet resistance of 110Ω/□, a resistivity of 1.65×10^-3Ω· cm and a transparency of 90% .     

Fabrication of carbon nanotube based transparent conductive thin films using layer-by-layer technology

This paper presents a simple and convenient process for the fabrication of carbon nanotube based optically transparent and electrically conductive thin films. Single-walled carbon nanotubes (SWNTs) are chemically treated to introduce negatively charged carboxylic groups on their surfaces, so that a stable SWNT aqueous dispersion can be obtained without any surfactant. The substrate surface is modified by a layer-by-layer nanoassembly technique, in which a positively charged hydrophilic polymer molecular layer is formed on the top of the substrate. This helps the SWNT dispersion to be cast onto the substrate using convenient wet coating techniques and increases the bonding force between the thin films and the substrates. Using the developed process, large sizes of conductive pure SWNT thin films that are uniform and highly transparent have been fabricated.     

Influence of substrate bias on the composition of SiC thin films fabricated by PECVD and underlying mechanism

The influence of the substrate bias on the composition of SiC thin films synthesized by plasma-enhanced chemical vapor deposition was studied. Our results indicate that the ratio of Si to C in the thin films is almost stoichiometric at a bias of − 300 V, whereas excessive carbon is observed in the films if the bias is lower or higher. Very little oxygen can be detected in the film produced without biasing. The effects of the bias on the composition of the thin films can be attributed to the interaction between the positive ions in the plasma and the surface atoms. The underlying mechanism is also discussed.     

退火处理对ITO和ITO:Zr薄膜性能的影响

利用磁控溅射在室温条件下沉积ITO薄膜和ITO：Zr薄膜,对比研究在空气中退火处理对ITO和ITO：Zr薄膜性能的影响。结果表明,Zr的掺杂促进了（400）晶面的取向,随着退火温度的升高,薄膜表面颗粒增大,表面粗糙度有所降低。室温下Zr的掺杂显著改善了薄膜的光电性能,随着退火温度的升高,ITO和ITO：Zr薄膜的方阻都表现为先降后升的趋势,ITO：Zr薄膜在较低的退火温度下可见光透过率就可达到80%以上,直接跃迁模型确定的光学禁带宽度Eg呈现了先升后降的变化。ITO：Zr薄膜比ITO薄膜显示了更高的效益指数,揭示了ITO：Zr薄膜具有更好的光电性能。     

Field emission enhancement of ZnO nanorod arrays with hafnium nitride coating

Vertically well-aligned single crystal ZnO nanorod arrays were synthesized and enhanced field electron emission was achieved with hafnium nitride (HfN_x) coating under proper sputtering condition. HfN_x films with various composition have been coated on ZnO nanorod arrays using a reactive direct current (DC) magnetron sputtering system. Morphology and crystal configuration of the ZnO nanorod arrays were investigated by scanning electron microscopy and X-ray diffraction. The field emission properties of the coated and uncoated ZnO nanorod arrays were characterized. The as-grown ZnO nanorod arrays showed a turn-on electric field of 6.60 V μm^− 1 at a current density of 10 μA cm^− 2 and an emission current density of 1 mA cm^− 2 under the field of 9.32 V μm^− 1. While the turn-on electric field of the coated ZnO nanorod arrays sharply decreased to 2.42 V μm^− 1, an emission current density of 1 mA cm^− 2 under the field of only 4.30 V μm^− 1 can be obtained. A method to accurately measure the work function of the coated films was demonstrated.     

Study on adhesion and electro-optical properties of ITO films on flexible PET substrate

High-quality ITO films on flexible PET substrate were prepared by RF magnetron sputtering at low deposition temperature with different Ar gas sputtering pressure.Adhesion and electro-optical properties of ITO films were investigated as a function of Ar partial pressure.The sputtering conditions provide very uniform ITO films with high transparency (＞85% in 400-760 nm spectra) and low electrical resistivity (1.408×10-3-1.956×10-3 Ω·cm).Scratch test experiments indicate that there is a good adhesion property between ITO films and PET substrate, the critical characteristic load increases from 16.5 to 23.2 N with increasing Ar sputtering pressure from 0.2 to 1.4 Pa.     

Optical properties of Se or S-doped hydrogenated amorphous silicon thin films with annealing temperature and dopant concentration

We report the effects of the thermal annealing and dopant concentration on the optical properties of Se or S-doped hydrogenated amorphous silicon thin films. The Se and S-doped a-Si:H (a-Si,Se:H and a-Si,S:H) thin films were prepared by glow discharge plasma enhanced chemical vapor deposition (GD-PECVD) on 7059 corning glass. The films were subsequently annealed in vacuum in the temperature range from 100 to 500 °C. Influence of doping and annealing was examined by means of optical transmission spectroscopy of the films in the wavelength range of 300-1100 nm taken at room temperature. The absorption coefficients and refractive indices decreased as the annealing temperature increased from 100 to 300 °C and then increased again as the annealing temperature further increased to 500 °C, while the highest bandgap was observed at 300 °C for all of the samples. For a given dopant concentration bandgap was observed to be higher in a-Si,S:H than a-Si,Se:H thin films.     

Effect of precursor concentration on the properties of ITO thin films

Tin-doped indium oxide (ITO) thin films have been prepared by the spray pyrolysis method using indium chloride as a precursor and stannic chloride as a dopant. The effect of a precursor concentration on the structural, morphological, electrical and optical properties of films has been studied. The concentration of InCl₃ in the spraying solution is varied from 6.25 to 37.5 mM keeping doping percentage of tin fixed at its optimized value of 5 wt.%. Bare glass is used as a substrate and oxygen as the carrier and reaction gas. X-ray diffraction (XRD) patterns show that films are polycrystalline and their crystallinities are dependent on the precursor concentration. A surface morphology has been observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The typical ITO film has minimum resistivity value of 2.71 × 10⁻³ Ω cm, whose carrier concentration and mobility were 7.45 × 10¹⁹ cm⁻³ and 31 cm²/(V s), respectively. In addition, the best ITO film has optical transmittance of 94.4% and figure of merit 1.20 × 10⁻³ Ω⁻¹.     

Influence of temperature and layers on the characterization of ITO films

In this paper, the effects of high heating temperature on electrical and optical properties of transparent indium tin oxide (ITO) films were investigated, which is a topic that has received little attention from previous studies. Uniform and transparent indium tin oxide (ITO) films were deposited onto quartz glass substrates through a sol–gel process. Specifically, the microstructure and phase of the films were analyzed by AFM, AES, and XRD. The sheet resistance and optical transmittance of the films were measured using the four-point probe method and spectrophotometer, respectively. The grain size of the ITO film was refined when it heated at 800 °C. The influence of coating layers on electrical and optical properties was also discussed. With the rise of heating temperature from 400 to 800 °C, the optical transmittance of the films climbed from 76 to 93% (750 °C). With the increase of dip-coating layers from 3 to 7, their sheet resistance varied from 642.1 to 241.0 Ω/□.     

磁控溅射法制备Cu_2ZnSnS_4薄膜及其性能表征

利用磁控溅射法将Cu/Sn/Zn S前驱体沉积在钙钠玻璃基片上,再通过硫化该前驱体制备Cu2ZnSnS4薄膜。利用X射线衍射仪、拉曼光谱仪、扫描电子显微镜、能谱仪、霍尔效应测量系统和紫外可见分光光度计研究了Cu2ZnSnS4薄膜的微观结构、表面形貌、化学成分、电学和光学性能。结果表明,CZTS薄膜的微观结构依赖于硫化温度和时间。在480℃硫化3 h的薄膜为沿(112)晶面择优取向生长的纯相CZTS薄膜,该薄膜的禁带宽度是1.51 e V,其电阻率和载流子浓度分别为0.39Ω·cm和4.07×1017cm-3。     

Synthesis of layered birnessite-type manganese oxide thin films on plastic substrates by chemical bath deposition for flexible transparent supercapacitors

Layered birnessite-type manganese oxide thin films are successfully fabricated on indium tin oxide coated polyethylene terephthalate substrates for flexible transparent supercapacitors by a facile, effective and inexpensive chemical bath deposition technology from an alkaline KMnO₄ aqueous solution at room temperature. The effects of deposition conditions, including KMnO₄ concentration, initial molar ratio of NH₃·H₂O and KMnO₄, bath temperature, and reaction time, on the electrochemical properties of MnO₂ thin films are investigated. Layered birnessite-type MnO₂ thin films deposited under optimum conditions display three-dimensional porous morphology, high hydrophilicity, and a transmittance of 77.4% at 550 nm. A special capacitance of 229.2 F g⁻¹ and a capacitance retention ratio of 83% are obtained from the films after 1000 cycles at 10 mV s⁻¹ in 1 M Na₂SO₄. Compressive and tensile bending tests show that as-prepared MnO₂ thin film electrodes possess excellent mechanical flexibility and electrochemical stability.     

SiC衬底金刚石薄膜的制备与性能表征

用热丝CVD法,以丙酮和氢气为碳源,在SiC衬底上沉积金刚石薄膜,提出了分步变参数沉积法制备超细晶粒金刚石复合薄膜的新工艺.结果表明,合理控制工艺条件的新工艺,对金刚石薄膜质量、形貌和粗糙度、薄膜与衬底间的附着力以及薄膜的摩擦系数有显著影响,金刚石薄膜的平均晶粒尺寸从3 μm减小到0.3 μm,拉曼特征峰显示超细晶粒金刚石薄膜特征,涂层附着力好,超细晶粒金刚石薄膜的表面粗糙度和摩擦系数值显著下降,对获取实用化的SiC在基体上沉积高附着强度、低粗糙度金刚石薄膜的新技术具有重要的意义.     

Fabrication and characterization of Schottky diodes and thin films based on poly(o-toluidine) deposited by spincoating technique

Poly(o-toluidine) (POT) thin films were fabricated by spin coating on bare glass and indium–tin–oxide (ITO)-coated glass substrates, from a solution of poly(o-toluidine) in chloroform. The optical transmittance of the as-deposited and doped films was measured in the 250–1200 nm wavelength range. These measurements showed that the optical band gaps of the undoped and doped polymer films are on the order of 3.28 and 2.7 eV, respectively, and that doping increases absorption in the near infrared region. The FT-Raman measurement on spincoated POT film is comparable to that of polyaniline. The electrochemical properties of those thin films are presented using cyclic voltammetry. ITO/POT/Al devices were fabricated by thermal evaporation of aluminum circular contacts on films deposited on ITO-coated glass. The current–voltage characteristics of the devices indicate a Schottky diode-type behavior. The current–voltage characteristics can be fitted using the modified Shockley equation. The diode parameters were calculated from I–V characteristics and discussed. On the other hand, capacitance of these structures decreased with increasing frequency.     

Development on transparent conductive ZnO thin films doped with various impurity elements

A general review of recent research progress in fabricating transparent conductive ZnO thin films by means of intentional doping and codoping with In,Ga,Al,Mg,Li,F,H,N,and P,divided into metals and nonmetals,is presented in this article.The main emphasis is placed on introducing and discussing the recent research achievements on the mechanisms of the incorporation of these impurities,and their effects on the electrical and optical properties.Lastly,this article concludes with a summary of the present state of investigations on doping elements in fabricating functional ZnO thin films for photoelectric applications,and with our personal view of the perspective of future studies on doped ZnO thin films.     

Preparation and characteristics of indium tin oxide (ITO) thin films at low temperature by r.f. magnetron sputtering

Low resistivity and highly transparent ITO conducting films for solar cell applications were fabricated at low temperature by r.f. Magnetron sputtering. ITO films were deposited on glass and silicon substrate. Electrical, optical, structural and morphological properties of the ITO films were investigated in terms of the preparation conditions. The annealing treatment has improved the properties of the ITO films at different degree. The maximum transmittance of the obtained ITO films in the visible range is over 92%, and the low resistivity for the ITO films are about 3.85×10-4Ω·cm at 80℃, 80 W after annealing.     

Microstructures and electrical conductance of silver nanocrystalline thin films on flexible polymer substrates

Using sputtering technique, silver nanocrystalline thin films were deposited on two different polymer substrates, namely pretreated nylon and polyester fabrics, under identical conditions. It is found that the difference of the electrical conductance between the two samples is quite large. The highest conductivity obtained from the coated nylon fabric is 2.4 × 10⁷ Sm^− 1, indicating the feasibility to fabricate wearable electrodes using silver coated fabrics. However, the electrical conductance of the coated polyester fibre is found to be lower by six orders of magnitude. Transmission electron microscopy reveals that the silver grains coated on the polyester fibre are spatially separated while the silver grains coated on the nylon fibre are connective. The pre-deposition surface conditions of the fibres are suggested to be responsible to the remarkable differences in the electrical conductance and microstructures of the silver nanocrystalline films.     

Conductive and transparent Bi-doped ZnO thin films prepared by rf magnetron sputtering

Bi-doped ZnO thin films were grown on glass substrates by ratio frequency (rf) magnetron sputtering technique and followed by annealing at 400 °C for 4 h in vacuum (~ 10^− 1 Pa). The effect of argon pressure on the structural, optical, and electrical properties of the Bi-doped films were investigated. The XRD patterns show that the thin films were highly textured along the c-axis and perpendicular to the surface of the substrate. Some excellent properties, such as high transmittance (about 85%) in visible region, low resistivity value of 1.89 × 10^− 3 W cm and high carrier density of 3.45 × 10²⁰ cm^− 3 were obtained for the film deposited at the argon pressure of 2.0 Pa. The optical band gap of the films was found to increase from 3.08 to 3.29 eV as deposition pressure increased from 1 to 3 Pa. The effects of post-annealing treatments had been considered. In spite of its low conductivity comparing with other TCOs, Bi-doping didn't appreciably affect the optical transparency in the visible range of ZnO thin films.     

Growth of CdS thin films and nanowires for flexible photoelectrochemical cells

In this study, cadmium sulfide (CdS) nanocrystal thin films and nanowires have been deposited onto mechanically flexible substrates via dc-electrodeposition, which is a very suitable technique for large area manufacturing. For the first time with this study, flexible CdS nanocrystal thin films were integrated into photoelectrochemical (PEC) cells and their performances were compared with CdS nanowires. It has been demonstrated that PEC performance of both nanocrystal thin films and nanowires were a strong function of production conditions such as deposition time and voltage. The maximum power conversion efficiency of the CdS nanocrystal thin films obtained in this study was 0.3%. On the other hand, higher efficiencies (about 1.4%) were observed for the CdS nanowires. UV-vis analysis confirmed that both transmittance and band gap energies of the CdS nanowires were lower than that of CdS nanocrystal thin films. X-ray diffraction analysis revealed that both nanocrystal thin films and nanowires have a preferred orientation at 26° (2θ), which can be attributed to the CdS (0 0 2) structure.