An investigation on linear optical properties of dilute Cr doped ZnO thin films synthesized via sol-gel process

Cr doped ZnO thin films were prepared via sol-gel method. The effects of dopant concentration (0%, 1.5% and 3%) annealing temperature and film thickness on UV-Vis spectra of prepared films were investigated. Also, the thickness and surface topology of thin films were investigated by thickness profile meter (DEKTAK) and Atomic Force Microscopy (AFM), respectively. In addition, the band gap and Urbach energy of prepared films were calculated completely for the samples. The results showed that by increasing the dopant concentrations, the microstrain of the prepared thin film structures also increases while the band-gap values decrease. Meanwhile, an increase in annealing temperature makes a decrease in band gap and microstrain of thin films. The increase in thickness resulted in red shift in band gap and reduction in interior microstrains.     

EFFECT OF ANNEALING TREATMENT ON THE STRUCTURE OF CdS FILMS

The effect of annealing treatment on the structure of CdS films was investigated. The cadmium sulfide thin films were prepared by chemical bath deposition, and were annealed at nitrogen atmosphere at different temperatures. The films were characterized by SEM and XPS (X-ray photoelectron spectroscopy). X-ray photoelectron spectroscopy was used to examine the chemical states on the CdS films surface. It was found that thermal annealing could produce large grains of CdS thin films, remove the air contamination and reduce the oxygen content on the CdS films surface. Therefore, the CdS films changed more uniform and smoother surface after thermal annealing.     

退火温度对锗薄膜光学性能和表面结构的影响

研究了退火温度对电子束蒸发制备的锗薄膜光学性能和表面结构的影响规律.在硅基底上制备了厚度约850 nm的Ge薄膜,分别在350、400、450和500℃下进行退火.通过红外光谱仪测试了薄膜的透射率变化,采用光谱反演法得到了薄膜折射率和消光系数的变化规律,使用X射线衍射和原子力显微镜测试了样品的结晶特性和表面形貌.结果 ...     

Characterization of shape-memory alloy thin films made up from sputter-deposited Ni/Ti multilayers

A novel fabrication process for Ni–Ti shape-memory alloy thin films is presented. This process is based on the appropriate annealing of sputter-deposited Ni/Ti multilayers. X-ray diffraction shows that interdiffusion of the two constituents results either in the amorphization of the multilayer structure after annealing at 330°C or in the recrystallization as a Ni–Ti intermetallic compound after annealing at temperatures above 400°C. A single 30 min annealing step in the temperature range from 400 to 800°C is sufficient to obtain Ni–Ti films showing martensitic phase transformations and the shape-memory effect. The influence of increasing annealing temperature on the transformation behavior is investigated by differential scanning calorimetry. The evolution of the transformation temperatures is found to be qualitatively similar to conventional sputter-deposited Ni–Ti films. The corresponding microstructure is studied by transmission electron microscopy. A very fine-grained structure is observed even after annealing at 800°C. The film composition can be varied by adjusting the thickness ratio of the individual Ti and Ni layers. Transformation curves of films with nominal compositions of 49.5 and 54.0 at.% Ti are compared. It is demonstrated that Ni–Ti films made up from multilayers may possess an intrinsic “two-way” shape-memory effect, which is a very interesting feature in view of the development of thin film micro-actuators.     

Effect of annealing temperature on structure and electrochemical properties of LiCoO2 cathode thin films

LiCoO2 thin films, which can be used as a cathode material in microbatteries, were deposited using radio frequency (r.f.) magnetron sputtering system from a LiCoO2 target and in an O2+Ar atmosphere.The films were characterized by various methods such as XRD, SEM and AFM.The LiCoO2 films were annealed in air at 300, 500, 700 and 800 ℃ respectively.The effect of the annealing temperature on the structure, the surface morphology and the electrochemical properties of the films were investigated.The LiCoO2 thin film deposited at room temperature is amorphous and has smaller grain size.With increasing of annealing temperature, the crystallinity of the films is promoted.When the annealing temperature increases to 700 ℃, the films have a perfect crystalline LiCoO2 phase.The LiCoO2 thin film without annealing has no discharge plateau and small discharge capacity (about 27 μAh·cm-2μm).The discharge capacity increases with the increasing of annealing temperature and reaches 47 μAh·cm-2μm for the film annealed with 700 ℃, which also shows the typical discharge plateau of 3.9 V.The cycle performance of LiCoO2 thin films of as grown and annealed at different temperatures were studied.In the case of the film without thermal treatment, the capacity fading is much faster than that of the film annealed at different temperature, showing about 40% capacity loss only after 25 cycles.However, in the case of the film annealed at 700 ℃, the capacity reaches to steady state gradually and maintained constantly with cycling.After 25 times cycling, the discharge capacity of the film annealed at 700 ℃ decreases to about 36.9 μAh·cm-2·μm, only 0.8% capacity loss per cycle.     

热处理效应对Sn-Al与Sn-Ca纳米薄膜的电磁屏蔽机制

利用溅镀Sn-Al纳米薄膜和Sn-Cu纳米薄膜讨论结晶机制与膜厚对电磁波屏蔽特性的影响,比较了Sn-Al和Sn-Cu薄膜的高温显微组织、导电性与电磁波屏蔽性能。结果表明,高温处理提高了Sn-Al纳米薄膜的电磁波屏蔽性。在低频条件下,高Cu摩尔浓度的Sn-Cu纳米薄膜不能有效改善电磁波屏蔽性;高温处理后,低Cu摩浓度的Sn-Cu纳米薄膜能提高低频的电磁波屏蔽性,而高频下的电磁波屏蔽性则呈相反趋势。     

Metallic Glass Nano-composite Thin Films for High-performance Functional Applications

Metallic glass nanocomposite thin films were synthesized for an immiscible Ag-Cu alloy system by magnetron sputtering. The structure of the films was unique, consisting of homogeneously dispersed nanocrystallites in an amorphous matrix. The size and volume fraction of the nanocrystallites increased with increasing film thickness resulting in increased elastic modulus and hardness. The high electrical conductivity of the nanocomposite films was examined by a valence-band study, which showed that exchange interaction between Ag and Cu in the nanocomposite structure resulted in enhanced charge carrier concentration. The inverse correlation between electrical conductivity and film thickness was explained by surface and interface scattering of electrons with increasing volume fraction of nanocrystallites. The small temperature dependence of conductivity was attributed to the distorted Fermi surface of the nanocomposite films resulting in a greater contribution from structure scattering, which is temperature-independent.     

Induced effects of Cu underlayer on（111） orientation of Fe50 Mn50 thin films

Effects of Cu underlayer on the structure of Fe50 Mn50 films were studied. Samples with a structure of Fe50 Mn50 (200 nm)/Cu(tcu) were prepared by rnagnetron sputtering on thermally oxidized silicon substrates at room temperature. The thickness of Cu underlayer varied from 0 to 60 nm in the intervals of 10 nm. High-vacuum annealing treatments, at different temperatures of 200, 300 and 400℃ for 1 h, respectively, on the Fe50Mn50 (200 nm)/Cu(20 nm) thin films were performed. The surface morphologies and textures of the samples were measured by field emission scan electronic microscope (FE-SEM) and X-ray diffraction(XRD). Energy dispersive X-ray spectroscopy (EDX) and Auger electron spectroscopy(AES) were used to analyze the compositional distribution. It is found that Cu underlayer has an obvious induce effect on (111) orientation of Fe50 Mn50 thin films. The induce effects of Cu on (111) orientation of Fe50 Mn50 changed with the increase of Cu layer thickness and the best effect was obtained at the Cu layer thickness of 20 nm. High-vacuum annealing treatments cause the migration of Mn atoms towards surface of the film and interface between Cu layer and substrate. With the increasing annealing temperature, migration of Mn atoms is more obvious, which leads to a Fe-riched Fe-Mn alloy film.     

铁酸铋薄膜的溶胶-凝胶法制备及电性能研究进展

铁酸铋是唯一一种在室温下存在的单相多铁材料,因其具有较高的铁电居里温度、较大的剩余极化强度、较小的禁带宽度和多铁特性,受到国内外的广泛关注。溶胶-凝胶法是制备铁酸铋薄膜的一种常见方法。综述了近年来溶胶-凝胶法制备铁酸铋薄膜的研究进展,详细阐述了制备工艺参数(前驱液、退火温度、退火气氛、底电极)与掺杂对铁酸铋薄膜电性能的影响;分析了不同制备工艺导致薄膜电性能出现差异的原因;归纳、总结出了目前溶胶-凝胶法制备铁酸铋薄膜的较佳工艺条件;最后,指出了亟待解决的问题。     

Influence of Annealing Temperature on the Microstructure and Electrical Properties of Indium Tin Oxide Thin Films

Indium tin oxide(ITO) thin films were prepared on alumina ceramic substrates by radio frequency magnetron sputtering.The samples were subsequently annealed in air at temperatures ranging from 500 to 1,100 °C for 1 h.The influences of the annealing temperature on the microstructure and electrical properties of the ITO thin films were investigated,and the results indicate that the as-deposited ITO thin films are amorphous in nature.All samples were crystallized by annealing at 500 °C.As the annealing temperature increases,the predominant orientation shifts from(222)to(400).The carrier concentration decreases initially and then increases when the annealing temperature rises beyond1,000 °C.The resistivity of the ITO thin films increases smoothly as the annealing temperature increases to just below900 °C.Beyond 900 °C,however,the resistivity of the films increases sharply.The annealing temperature has a significant effect on the stability of the ITO/Pt thin film thermocouples(TFTCs).TFTCs annealed at 1,000 °C show improved hightemperature stability and Seebeck coefficients of up to 77.73 μV/°C.     

磁控溅射法制备硅钼薄膜及其性能表征

用射频磁控溅射法在硅基底上成功制备出具有低电阻率的单一四方相二硅化钼薄膜，并通过X射线衍射仪、原子力显微镜及四探针电阻测试仪对退火前后的薄膜样品进行了结构和电学性能分析。结果表明：薄膜的电学特性强烈依赖于薄膜的微结构和相组成。沉积态薄膜主要为非晶结构。经高温退火后，薄膜的晶态结构发生显著的变化，晶化效果明显提高，薄膜方阻大幅降低。     

Synthesis and characterization of Cu2ZnSnS4 thin films grown by PLD: Solar cells

As-deposited and annealed Cu₂ZnSnS₄ (CZTS) thin films have been synthesized onto Mo coated glass substrates at different deposition times using pulsed laser deposition (PLD) technique. The effect of deposition time (film thickness) and annealing onto the structural, morphological, compositional and optical properties of CZTS thin films have been investigated. The polycrystalline CZTS thin films with tetragonal crystal structure have been observed from structural analysis. FESEM and AFM images show the smooth, uniform, homogeneous and densely packed grains and increase in the grain size after annealing. The internal quantitative analysis has been carried out by XPS study which confirms the stoichiometry of the films. The optical band gap of CZTS films grown by PLD is about 1.54 eV, which suggests that CZTS films can be useful as an absorber layer in thin film solar cells. Device performance for deposited CZTS films has been studied.     

Time and temperature-dependent changes in the structural properties of tetrahedral amorphous carbon films

The time and temperature-dependent changes in the structural properties of tetrahedral amorphous carbon (ta-C) films were accessed continuously by Raman spectroscopy. It has been found that a film of 70-nm thickness remains structurally stable after annealing in air at up to 300°C for 4 h. Although some degree of graphitization was observed on a film annealed at 400°C, the film begins to oxidize and lose thickness only after annealing at 500°C for more than 2 h. This reflects the high thermal stability of the films. In general, annealing results in a narrowing and an upshifting of the G-band together with an increase in the I_D/I_G ratio. Most of these changes were observed during the first 2 h of annealing, after which the structure of the film appears to stabilize, with the exception at 500°C in which the film deteriorates further as oxidation occurs. It was also observed that thin film has better thermal stability against graphitization than thick film.     

退火对栅介质SrHfON薄膜性能的影响

采用射频磁控溅射法在Si衬底上制备新型栅介质SrHfON薄膜。采用X射线衍射(XRD)仪、高分辨透射电镜(HRTEM)和X射线光电子谱(XPS)分析退火对SrHfON薄膜的界面形态、薄膜的结构和电学性能的影响。结果表明,SrHfON薄膜经900℃退火后仍保持非晶态,表现出良好的热稳定性。SrHfON薄膜与Si衬底的界面主要由HfSixOy和SiO2组成。以SrHfON薄膜为栅介质的MOS电容结构具有较小的漏电流密度,并且漏电流密度随着退火温度的升高而减小。在外加偏压(Vg)为+1V时样品在沉积态和900℃退火后的漏电流密度分别为4.3×10-6和1.2×10-7A/cm2。研究表明,SrHfON薄膜是一种很有希望替代SiO2的新型栅介质材料。     

Preparation and optical characteristics of ZnO films by chelating sol-gel method

The effect of different annealing temperatures on the structure, morphology, and optical properties of ZnO thinf ilms prepared by the chelating sol-gel method was investigated. Zinc-oxide thin films were coated on quartz glass substrates by dip coating. Zinc nitrate, absolute ethanol, and citric acid were used as precursor, solvem, and chelating agent, respectively. The results show that ZnO films derived flom zinc-citrate have lower crystallization temperature (below 400℃),and that the crystal structure is wurtzite. The films, treated over 500℃, consist of nano-pardcles and show to be porous at 600℃. The particle size of the film increases with the increase of the annealing temperature. The largest particle size is 60 nm at 600℃. The optical transmittances related to the annealing temperatures become 90% higher in the visible range. The film shows a stalting absorption at 380 ran, and the optical band-gap of the thin film (fired at 500℃) is 3.25 eV and close to the intrinsic band-gap of ZnO (3.2 eV).     

New process for synthesis of ZnO thin films: Microstructural, optical and electrical characterization

Nanocrystalline ZnO thin films were prepared on glass substrates by using spin coating technique. The effect of annealing temperature (400-700 °C) on structural, compositional, microstructural, morphological, electrical and optical properties of ZnO thin films were studied by X-ray diffraction (XRD), Energy dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), High Resolution Transmission Microscopy (HRTEM), Scanning Electron Microscopy (SEM), Electrical conductivity and UV-visible Spectroscopy (UV-vis). XRD measurements show that all the films are nanocrystallized in the hexagonal wurtzite structure and present a random orientation. The crystallite size increases with increasing annealing temperature. These modifications influence the optical properties. The AFM analysis revealed that the surface morphology is smooth. The HRTEM analysis of ZnO thin film annealed at 700 °C confirms nanocrystalline nature of film. The SEM results shows that a uniform surface morphology and the nanoparticles are fine with an average grain size of about 40-60 nm. The dc room temperature electrical conductivity of ZnO thin films were increased from 10⁻⁶ to 10⁻⁵ (Ω cm)⁻¹ with increase in annealing temperature. The electron carrier concentration (n) and mobility (μ) of ZnO films annealed at 400-700 °C were estimated to be of the order of 4.75-7.10 × 10¹⁹ cm⁻³ and 2.98-5.20 × 10⁻⁵ cm² V⁻¹ S⁻¹.The optical band gap has been determined from the absorption coefficient. We found that the optical band gap energy decreases from 3.32 eV to 3.18 eV with increasing annealing temperature between 400 and 700 °C. This means that the optical quality of ZnO films is improved by annealing.It is observed that the ZnO thin film annealing at 700 °C has a smooth and flat texture suited for different optoelectronic applications.     

退火温度对Ba_(0.6)Sr_(0.4)TiO_3薄膜晶化及介电性能的影响

用改善的溶胶凝胶(Sol-Gel)法制备了钛酸锶钡(Ba_0.6Sr_0.4TiO_3, BST)薄膜,研究了退火温度对薄膜晶化及介电性能的影响.X射线衍射表明,由于薄膜较薄,各温度下衍射峰强度均微弱,但呈(110)择优取向,随温度的升高峰强度逐渐增加,也出现其他晶向的衍射峰.扫描电镜和原子力显微镜表明,改善的BST薄膜表面形貌光滑致密、无裂纹、无缩孔,随温度的升高薄膜晶化增强、晶粒逐渐长大、粗糙度增加.40 V外加电压下的介电性能大幅度提高,介电调谐率大于30%,介电损耗约0.02,其中,650 ℃对应介电调谐率45.1%和介电损耗0.0187.同时,就有关结构、介电性能及退火温度的关系进行了讨论.     

具有Al2O3阻挡层的HfO2栅介质膜的界面和电学性能的表征

研究了经过700℃快速热退火的并在Si界面处插入Al2O3阻挡层的HfO2栅介质膜的界面结构和电学性能.X射线光电子谱表明,退火后,界面层中的siOx转化为化学当量的SiO2,而且未发现铪基硅酸盐和铪基酸化物.由电学测试提取出等效栅氧厚度为2.5nm,固定电荷密度为-4.5×1011/cm2.发现Al2O3阻挡层能有效地阻止Si原子扩散进入HfO2薄膜,进而改善HfO2栅介质膜的界面和电学性能.     

Effects of annealing temperature and time on microstructure and magnetic properties of Pr-Co thin films

A series of Pr-Co thin films were deposited on the Si (100) substrates with Cr underlayer by magnetron sputtering. The effects of both the post-annealing temperature and the annealing time on the microstructure and magnetic properties for the Pr-Co films were studied systemati- cally. The as-deposited Pr-Co thin films are mostly amorphous and tend to crystallize after annealing at temperatures above 600 C. When the annealing time is increased, the films show a complicated structure with various phases coexisting. Accordingly, the as-deposited film and low temperature annealed films are soft magnets and films annealed at temperatures beyond 600 C tend to be hard magnets. When the annealing time is increased from 5 min to 2 h, the films transfer from hard magnets to soft again. The sample annealed at 600 C for 10 min shows the largest coercivity of 0.59 T.     

射频反应磁控溅射法制备ZnO:Al透明导电薄膜的光电性能

室温下采用射频(RF)反应磁控溅射技术在玻璃衬底上沉积具有(002)择优取向的透明导电Al掺杂ZnO(AZO)薄膜。XRD结果表明,制备的AZO薄膜为多晶,具有c轴择优取向。退火处理能提高其结晶度。在Al靶射频功率为40W,ZnO靶射频功率为250W,氩气流量为15mL/min的条件下,获得200nm厚的薄膜电阻率约3.8×10-3?·cm,在可见光范围内有很好的光透过率。