Preparation and characterization of Ce-doped BaTiO3 thin films by r.f. sputtering

Ce-doped BaTiO₃ thin films prepared on silicon-platinium by r.f. sputtering has been investigated. BaTiO₃ doped with 5.5 mol%CeO₂ thin film was deposited at 550°C substrate temperature in an Ar atmosfere. The crystal structure and shape were examined by X-ray diffraction and scanning electron microscopy with EDAX. Analysis by X-ray diffraction patterns show that the crystalline film with a cubic structure of BaTiO₃, was obtained. The surface morphology (roughness, the grain size and the droplet size) of the thin film surface was examined by atomic force microscopy (AFM). The grain size is about 160 nm, the droplet size is about 0.675 m and the roughness is 36.88 nm. EDAX analysis established a composition of the film to be identical with that of the target (BaTiO₃ doped with 5.5 mol%CeO₂). The broad peak in the capacitance versus temperature curve at the Curie point indicate that the r.f. sputtered Ce-doped BaTiO₃ film is ferroelectric. The values of the capacitance of the thin film at 1 KHz were found to be 86 pF and the loss dielectric was tan = 0.0875. The film exibits a dielectric anomaly peak at 23°C showing ferroelectric to paraelectric phase transition.     

La2O3-doped BaTiO3 thin films obtained by pulsed laser deposition

Abstract

La²O³-doped barium titanate (BaTiO³) thin films have been obtained by pulsed laser deposition. The structure and quality of deposited films were characterized by X-ray diffraction and scanning electron microscopy. A smooth surface was obtained when the films were deposited in 30 Pa ambient oxygen. The composition (elements and oxides) of the thin films were close to those of the target. The layer obtained by pulsed laser deposition from a target of BaTiO³ doped with 0.5 at.% La exhibits good dielectric characteristics: capacitance 88 pF, Curie temperature 59°C and dielectrics loss, tanδ, 0.084.     

Preparation of nitrogen-doped YSZ thin films by pulsed laser deposition and their characterization

The pulsed laser deposition technique was applied to deposit nitrogen-doped yttria stabilized zirconia (YSZ) thin films. The working parameters were varied in order to achieve a maximal nitrogen content. The films were characterized by SIMS, XPS, X-ray diffraction and optical spectroscopy. The surface topography was studied by AFM and HRSEM. The influence of the deposition parameters on the film properties is discussed.

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脉冲激光沉积法制备Pt薄膜的研究

采用脉冲激光沉积技术在(0001)取向的蓝宝石基片上外延生长了Pt单晶薄膜,研究了沉积温度和激光能量对Pt薄膜的晶体结构,表面形貌及电学性能的影响规律.X射线衍射(XRD)分析结果表明,在沉积温度650℃、激光脉冲频率1Hz和激光能量280mJ的条件下,制备得到的Pt(111)单晶薄膜,其(111)面ω摇摆曲线半高宽(FWHM)仅为0.068°.原子力显微镜(AFM)分析表明外延的Pt薄膜表面具有原子级平整度,其表面均方根粗糙度(RMS)约为1.776nm.四探针电阻测试结果显示薄膜方阻为1/962Ω/□,满足铁电薄膜的制备工艺对Pt底电极的要求.     

AgTaO3 and AgNbO3 thin films by pulsed laser deposition

Silver tantalate AgTaO₃ (ATO) and silver niobate AgNbO₃ (ANO) films have been grown on to the LaAlO₃ (001) and sapphire Al₂O₃ (0112, r-cut) single crystals by pulsed laser deposition technique from stoichiometric ATO and ANO targets. X-ray diffraction study revealed epitaxial quality of ATO and ANO films on the LaAlO₃ (001) whereas on the sapphire r-cut substrate they are preferential (110) and (001) oriented. To characterize microwave films properties in the range from 1 to 40 GHz, coplanar line interdigital capacitors were fabricated by photolithography and lift-off technique. ANO film capacitors show superior properties: frequency dispersion was as low as 13%, voltage tunability (40 V, 200 kV/cm) was about 4.6% at 20 GHz, loss tangent ∼0.106 at 20 GHz, K-factor = tunability / tanδ from 49% @ 10 GHz to 33% at 40 GHz.     

Growth and characterization of non-polar ZnO thin films by pulsed laser deposition

Non-polar ZnO thin films were fabricated on r-plane sapphire substrates by pulsed laser deposition at various temperatures from 100 to 500 °C. The effects of the substrate temperature on structural, morphological and optical properties of the films were investigated. Based on the X-ray diffraction analysis, the ZnO thin films grown at 300, 400 and 500 °C exhibited the non-polar (a-plane) orientation and those deposited below 300 °C exhibited polar (c-plane) orientation. In the optical properties of non-polar ZnO films, there were two photoluminescence peaks detected. The peaks (near-band edge emission, blue emission) are due to electron transitions from band-to-band and shallow donor level to valence band, respectively.     

离子束辅助脉冲激光沉积硼碳氮薄膜

以烧结B4C为靶材料、在氮离子束辅助下用脉冲激光沉积方法制备了三元化合物硼碳氮（BCN）薄膜.用X光电子谱和傅立叶变换红外谱方法表征了制备的薄膜.结果表明,膜层中包含B-C、N-C、B-N键等复合结构,以B-C-N原子杂化的形式结合成键,而并非各种成分的简单混合.还探讨了成膜过程和相关机理,离子束中的活性氮有效地和脉冲激光对B4C靶烧蚀产生的硼和碳结合成键,氮离子束的辅助还能在一定程度上抑制氧杂质进入膜层,给衬底适当加温有利于提高氮的含量并影响薄膜的化学结构.     

InGaZnO thin films grown by pulsed laser deposition

We fabricated InGaZnO (IGZO) ceramic target (In: Ga: Zn = 1: 1: 4 in atomic ratio) using solid-state reaction at ambient atmosphere, and deposited IGZO thin films on quartz glass at room temperature under various oxygen partial pressures using the pulsed laser deposition method. Influence of oxygen pressure on crystal structure, surface morphology, optical and electrical properties were investigated. It was found that all the films deposited at room temperature exhibit amorphous structure. On the other hand, the physical properties of the films like transparency, electron mobility, and free-electron concentration were found to be correlated to the oxygen pressure during the deposition and in turn to the possible oxygen vacancies or metallic interstitials in the films. The analysis of X-ray photoelectron spectra (XPS) of the films indicated that there are no metallic 3d states of In, Ga and Zn, suggesting that oxygen vacancies could be main defects that affect physical properties of the films.     

Low-temperature deposition of iridium thin films by pulsed laser deposition

Extremely smooth iridium (Ir) thin films were deposited on Si(1 0 0) substrate at lower temperature than 300 °C by pulsed laser deposition (PLD) technique using Ir target in a vacuum atmosphere. The crystal orientation, surface morphology, and resistivity of the Ir thin films were systematically determined as a function of substrate temperature. Well-crystallized and single-phase Ir thin films with (1 1 1) preferred orientation were obtained at substrate temperature of 200-300 °C. The surface roughness increased with the increasing of substrate temperature. Likewise, the room-temperature resistivity of Ir thin films decreased with increasing substrate temperature, showing a low value of (10.7±0.1) μΩ cm at 300 °C.     

ZnO thin films prepared by pulsed laser deposition

Zinc oxide (ZnO) thin films were deposited on soda lime glass substrates by pulsed laser deposition (PLD) in an oxygen-reactive atmosphere. The structural, optical, and electrical properties of the as-prepared thin films were studied in dependence of substrate temperature and oxygen pressure. High quality polycrystalline ZnO films with hexagonal wurtzite structure were deposited at substrate temperatures of 100 and 300 °C. The RMS roughness of the deposited oxide films was found to be in the range 2-9 nm and was only slightly dependent on substrate temperature and oxygen pressure. Electrical measurements indicated a decrease of film resistivity with the increase of substrate temperature and the decrease of oxygen pressure. The ZnO films exhibited high transmittance of 90% and their energy band gap and thickness were in the range 3.26-3.30 eV and 256-627 nm, respectively.     

Preparation of ferroelectric BaTiO3 thin films by metal organic chemical vapour deposition

Polycrystalline BaTiO₃ thin films have been successfully prepared on (100) silicon substrates at temperatures under 600° C by metal organic chemical vapour deposition using barium acetylacetonate and diisopropoxy-titanium-bis-(acetylacetonate). To vaporize the barium acetylacetonate, which is nonvolatile under 300° C and thermally unstable, an ultrasonic spraying technique was used. The substrate temperature had a great influence on the structure and composition of films and the single-phase BaTiO₃ films could be prepared at 500° C. At temperatures above 550° C the reaction between the film and the silicon substrate occurred to a large extent. The polarization-electric field (P-E) hysteresis loops and counter-clockwise direction of hysteresis in the high-frequency (1 MHz)C-V characteristics indicate that the BaTiO₃ films deposited on silicon using the present method are ferroelectric.     

激光溅射沉积后硒化制备CIGS薄膜

采用脉冲激光溅射沉积法( PLD)制备了Cu - In - Ga双层预制膜,通过固态源硒化后热处理的方法获得了CuInl - xGaxSe2(CIGS)薄膜,研究制备预制膜的工艺参数以及热处理温度对CIGS薄膜特性的影响.采用台阶仪、SEM、EDS、XRD和紫外分光光度计研究了薄膜的厚度、表面形貌、成分、物相结构以及光...     

Preparation of ferroelectric NaNbO(3) thin films on MgO substrate by pulsed laser deposition

We successfully fabricated good quality NaNbO(3) (NN) films on MgO substrate by pulsed laser deposition using a K-Ta-O (KTO) buffer layer. An SrRuO(3) (SRO) lower electrode layer was deposited on a KTO buffer layer/(100)MgO substrate and then the NN film was deposited on top. X-ray diffraction showed that the SRO and NN films were epitaxially grown on (100)MgO substrate. Transmission electron microscopy showed a crystallographic relationship of [001](NN)//[001](MgO) between NN and MgO. The relative dielectric constant, epsilon(r), and dielectric loss, tan delta, of the film were 350 and 0.05 at 1 kHz, respectively. The polarization vs. electric field (P-E) hysteresis loop of the NN film was characteristic of ferroelectric behavior.     

ITO thin films deposited by advanced pulsed laser deposition

Indium tin oxide thin films were deposited by computer assisted advanced PLD method in order to obtain transparent, conductive and homogeneous films on a large area. The films were deposited on glass substrates. We studied the influence of the temperature (room temperature (RT)-180 °C), pressure (1-6 × 10^− 2 Torr), laser fluence (1-4 J/cm²) and wavelength (266-355 nm) on the film properties. The deposition rate, roughness, film structure, optical transmission, electrical conductivity measurements were done. We deposited uniform ITO thin films (thickness 100-600 nm, roughness 5-10 nm) between RT and 180 °C on a large area (5 × 5 cm²). The films have electrical resistivity of 8 × 10^− 4 Ω cm at RT, 5 × 10^− 4 Ω cm at 180 °C and an optical transmission in the visible range, around 89%.     

Production of porous carbon thin films by pulsed laser deposition

Pulsed laser deposition (PLD) has been used together with the Glancing Angle Deposition (GLAD) technique [1 and 2] for the first time to produce highly porous structured films. A laser produced carbon plasma and vapour plume was deposited at a highly oblique incident angle onto rotating Si substrates, resulting in films exhibiting high bulk porosity and controlled columnar microstructure. By varying the substrate rotation rate, the shape of the microcolumns can be tailored. These results extend the versatility of the GLAD process to materials not readily deposited by means of traditional physical vapour deposition techniques.     

Nano-polycrystalline vanadium oxide thin films prepared by pulsed laser deposition

Nano-polycrystalline vanadium oxide thin films have been successfully produced by pulsed laser deposition on Si(100) substrates using a pure vanadium target in an oxygen atmosphere. The vanadium oxide thin film is amorphous when deposited at relatively low substrate temperature (500 degrees C) and enhancing substrate temperature (600-800 degrees C) appears to be efficient in crystallizing VOx thin films. Nano-polycrystalline V3O7 thin film has been achieved when deposited at oxygen pressure of 8 Pa and substrate temperature of 600 degrees C. Nano-polycrystalline VO2 thin films with a preferred (011) orientation have been obtained when deposited at oxygen pressure of 0.8 Pa and substrate temperatures of 600-800 degrees C. The vanadium oxide thin films deposited at high oxygen pressure (8 Pa) reveal a mix-valence of V5+ and V4+, while the VOx thin films deposited at low oxygen pressure (0.8 Pa) display a valence of V4+. The nano-polycrystalline vanadium oxide thin films prepared by pulsed laser deposition have smooth surface with high qualities of mean crystallite size ranging from 30 to 230 nm and Ra ranging from 1.5 to 22.2 nm. Relative low substrate temperature and oxygen pressure are benifit to aquire nano-polycrystalline VOx thin films with small grain size and low surface roughness.     

脉冲激光沉积技术制备薄膜锂电池

脉冲激光沉积(pulsed laser deposition,PLD)是20世纪80年代发展起来的一种全新的制备薄膜技术,具有沉积速率高,再现性能好等优点.近年来,利用PLD技术在全固态薄膜锂电池的研究中取得许多有意义的结果.一系列新型、高质量的电池薄膜材料被成功制备;原位组装的薄膜锂电池表现出良好的电化学性能.本文简要介绍了PLD技术的原理和特点;重点评述PLD在全固态薄膜锂电池阴极薄膜、阳极薄膜和电解质薄膜制备中的应用状况.     

Preparation of the hard CNx thin films using NO ambient gas by pulsed laser deposition

Pulsed laser deposition (PLD) technique has been widely used in thin film preparation because of its wonderful and excellent properties and amorphous carbon nitride (CN_x) thin films are recognized to have potential for applications like hard coating and electron field emission device. We have deposited CN_x thin films by KrF excimer laser – (λ= 248 nm) ablation of pure graphite target in pure NO gas ambient condition. In this paper, we have prepared the CN_x thin films at various ambient NO gas pressure of 1.3–26 Pa and laser fluence of 2– 5J cm^?2 on Si (100) substrate. We consider that the hardness of CN_x thin films improves due to the increase the nitrogen/carbon (N/C) ratio. The N/C ratio depended on the ambient NO gas pressure and laser fluence. We obtainedthe maximum N/C ratio of 1.0 at NO 3.3 Pa. The typical absorption of CN bonds such as sp² C–N, sp³ C–N, G band and D band were detected from the infrared absorption measurement by FTIR in the deposited CN_x thin films.