Optical and structural properties of sol-gel derived nanostructured CeO2 film

Sol-gel derived nanostructured CeO2 film was deposited on glass substrate using by dip-coating technique with annealing at 65℃.X-ray diffraction (XRD),scanning electron microscopy (SEM),Fourier transform infrared (FTIR),UV/vis and photoluminescence (PL) spectroscopy studies were employed to analyze the structural and optical properties of the sol-gel derived nanostructured CeO2 film.The average crystallite size was estimated from the XRD pattern using by Scherrer equation as about 3-4nm.An SEM micrograph shows that the film was porous in nature and crack free.The UV-visible absorption spectroscopic measurement results showed that the products had conspicuous quantum size effects.The absorption spectrum indicates that the sol-gel derived nanostructured CeO2 film has a direct bandgap of 3.23 eV and the photoluminescence spectra of the film show a strong band at 378 nm:it may have a promising application as an optoelectronic material.     

金属离子掺杂纳米TiO2薄膜光阳极的性能研究

采用溶胶-凝胶法在玻璃衬底上制备TiO2多孔薄膜,掺杂不同功函数的金属离子制备M-TiO2纳米薄膜电极,XRD、AFM,UV-Vis检测M-TiO2结构、形貌和性能.结果表明:掺杂摩尔分数2%的金属离子没有改变TiO2的晶格结构,但其吸收峰在可见光区都发生明显的红移,禁带宽度降低,掺杂后的M-TiO2电极比没有掺杂的T...     

Nanoporous characteristics of sol-gel-derived ZnO thin film

Sol-gel-derived nanoporous ZnO film has been successfully deposited on glass substrate at 200℃ and subsequently annealed at different temperatures of 300, 400 and 600℃. Atomic force micrographs demonstrated that the film was crack-free, and that granular nanoparticles were homogenously distributed on the film surface. The average grain size of the nanoparticles and RMS roughness of the scanned surface area was 10 nm and 13.6 nm, respectively, which is due to the high porosity of the film. Photoluminescence (PL) spectra of the nanoporous ZnO film at room temperature show a diffused band, which might be due to an increased amount of oxygen vacancies on the lattice surface. The observed results of the nanoporous ZnO film indicates a promising application in the development of electrochemical biosensors due to the porosity of film enhancing the higher loading of bio-macromolecules (enzyme and proteins).     

溶胶凝胶法制备二维气敏光学薄膜及其氨气敏光学性能研究

本文研究了用溶胶凝胶法制作二维ＳｎＯ２；ＴｉＯ２混合薄膜并测量了它在氨气氛中的气敏透射谱，发现对低浓度委组最佳灵敏区显示出对二维薄膜厚度的依从性。利用这些现象可制成对低浓度敏感且有气体选择性的气敏传感器件。     

Ni/AAO纳米复合薄膜的制备及其光学性能

采用交流电化学沉积方法,以经过阶梯降压处理的多孔氧化铝(AAO)为模板,制备出Ni/AAO纳米复合薄膜。研究了薄膜的结构及光学性能。结果表明:Ni/AAO纳米复合薄膜中Ni呈线状均匀分布在AAO纳米孔隙中,直径与AAO孔径一致,约80nm,并沿[111]方向择优生长,具有面心立方结构。光谱分析表明,该复合薄膜的光学带隙为3.18eV,较AAO模板(3.38eV)自身红移;光致发光峰位于465nm,与AAO模板相同,发光强度较模板自身减弱。     

sol-gel法制备ZnO薄膜压敏电阻

利用sol-gel法在镀有Au底电极的单晶硅片上,制备掺有Bi2O3、Co2O3、Cr2O3和MnO2的ZnO薄膜压敏电阻。薄膜由旋涂法制备,并在300℃下预处理、600℃退火。制得的ZnO薄膜结晶良好。膜厚约为1μm,ZnO薄膜压敏电阻的非线性系数为15.1,压敏电压为3.037 V,漏电流为43.25μA。     

Structural and optoelectronic properties of nanostructured TiO2 thin films with annealing

About 480 nm thick titanium oxide (TiO₂) thin films have been deposited by electron beam evaporation followed by annealing in air at 300–600 °C with a step of 100 °C for a period of 2 h. Optical, electrical and structural properties are studied as a function of annealing temperature. All the films are crystalline (having tetragonal anatase structure) with small amount of amorphous phase. Crystallinity of the films improves with annealing at elevated temperatures. XRD and FESEM results suggest that the films are composed of nanoparticles of 25–35 nm. Raman analysis and optical measurements suggest quantum confinement effects since Raman peaks of the as-deposited films are blue-shifted as compared to those for bulk TiO₂ Optical band gap energy of the as-deposited TiO₂ film is 3.24 eV, which decreases to about 3.09 eV after annealing at 600 °C. Refractive index of the as-deposited TiO₂ film is 2.26, which increases to about 2.32 after annealing at 600 °C. However the films annealed at 500 °C present peculiar behavior as their band gap increases to the highest value of 3.27 eV whereas refractive index, RMS roughness and dc-resistance illustrate a drop as compared to all other films. Illumination to sunlight decreases the dc-resistance of the as-deposited and annealed films as compared to dark measurements possibly due to charge carrier enhancement by photon absorption.     

Title:Spray pyrolysis of tin selenide thin film semiconductor: effect of the selenium concentration on the thin film properties

Thin films of tin selenide (Sn_xSe_y) with an atomic ratio of r=≤[y/x]=0.5, 1 and 1.5 were prepared on a glass substrate at T= 470 ℃ using a spray pyrolysis technique. The initial materials for the preparation of the thin films were an alcoholic solution consisting of tin chloride (SnCl₄·5H₂O) and selenide acide (H₂SeO₃). The prepared thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy, scanning tunneling microscopy, scanning helium ion microscopy, and UV-vis spectroscopy. The photoconductivity and thermoelectric effects of the Sn_xSe_y thin films were then studied. The Sn_xSe_y thin films had a polycrystalline structure with an almost uniform surface and cluster type growth. The increasing atomic ratio of r in the films, the optical gap, photosensitivity and Seebeck coefficient were changed from 1.6 to 1.37 eV, 0.01 to 0.31 and-26.2 to-42.7 mV/K (at T= 350 K), respectively. In addition, the XRD patterns indicated intensity peaks in r=1 that corresponded to the increase in the SnSe and SnSe₂ phases.     

p型透明导电氧化物CuCrl-xMgxO2的制备及光电性能研究

采用溶胶-凝胶法制备了CuCr1-xMgO2粉末,压制烧结形成了CuCr1-xMgxO2陶瓷样品,研究了Mg2+掺杂量和压制压强对CuCrO2粉末和陶瓷的相组成、显微结构及光电性能的影响.结果表明:随着Mg2+掺杂量从0.01增加到0.07,所制CuCr1-xMgxO2粉末对紫外-可见光的吸收度增加,光学带隙宽度由3.25eV逐渐减小到2.86eV.随着Mg2+掺杂量或压制压强的增加,其相应陶瓷样品的电导率均先增大后减小.当Mg掺杂量x为0.03,压制压强为550 MPa时,制备的CuCr0.97Mg0.03O2陶瓷样品的电导率达到最大值,为19.8S/cm.     

非晶碳化硅薄膜的结构及其光学特性研究

采用等离子体增强化学气相沉积系统制备非晶碳化硅薄膜,通过控制反应气体中甲烷和硅烷的流量比R来调节薄膜中的碳/硅比,获得具有不同碳/硅比的薄膜结构.采用Raman、XPS以及FT-IR等技术手段对样品的结构进行表征.通过对样品吸收谱的测量,对样品的光学特性进行了研究.研究结果表明,薄膜中C-H键以及Si-C键含量的增加引起薄膜的光学带隙展宽,在R=10时薄膜的光学带隙达到2.4 eV.     

退火温度对p型CuCrO_2薄膜结构与光学性能的影响

采用射频磁控溅射法在石英玻璃衬底上制备CuCrO2薄膜,研究退火温度对CuCrO2薄膜结构和光学性能的影响。结果表明:未经退火处理的CuCrO2薄膜为非晶态,颗粒较小,可见光透射率仅为56%。退火处理能够改善CuCrO2薄膜的结构和透光性能。随着退火温度的升高,薄膜结晶化程度逐渐增强,孔洞缺陷逐渐减少,薄膜逐渐变得平整致密,薄膜的透光性能得到改善,薄膜的吸收边向短波方向移动。当退火温度为800℃时,薄膜的性能最优,可见光透射率达到70%。光学带隙宽度为3.06eV。     

sol-gel法制备ZAO薄膜的结构与光学性能研究

采用溶胶—凝胶法在普通玻璃衬底上制备了ZAO(ZnO:A1)薄膜,利用XRD、SEM、紫外—可见光谱和光致发光光谱对所制备的AZO薄膜进行了表征,研究了ZAO薄膜的结构和光学性能.结果表明:ZAO薄膜的微晶晶相与ZnO一致,且具有c轴择优取向;ZAO薄膜在可见光区的透过率超过了88％,在350～575 nm范围内有强的...     

SnO2纳米粉体的制备及其气敏性能研究

以Sn粒为原料,在柠檬酸体系中,用sol-gel法合成了具有四方晶系的SnO2粉体。用XRD、TEM对产物的组成、粒径、形貌进行了表征。结果表明:产物为平均粒径25 nm左右的圆球形颗粒。另外,在最佳工作温度300℃时,采用静态配气法测试了材料的气敏性能,发现SnO2对体积分数为5×10–5的氯气的灵敏度高达805,而且对其它气体有很好的抗干扰能力。元件的响应恢复特性良好,响应时间和恢复时间分别为3 s和7 s。     

Effect of processing parameter on structural,optical and electrical properties of photovoltaic chalcogenide nanostructured RF magnetron sputtered thin absorbing films

The aim of this work was to develop high quality of CuIn_1−xGa_xSe₂ thin absorbing films with x (Ga/In+Ga)<0.3 by sputtering without selenization process. CuIn_0.8Ga_0.2Se₂ (CIGS) thin absorbing films were deposited on soda lime glass substrate by RF magnetron sputtering using single quaternary chalcogenide (CIGS) target. The effect of substrate temperature, sputtering power & working pressure on structural, morphological, optical and electrical properties of deposited films were studied. CIGS thin films were characterised by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), Energy dispersive X-ray spectroscopy (EDAX), Atomic force microscopy (AFM), UV–vis–NIR spectroscopy and four probe methods. It was observed that microstructure, surface morphology, elemental composition, transmittance as well as conductivity of thin films were strongly dependent on deposition parameters. The optimum parameters for CIGS thin films were obtained at a power 100 W, pressure 5 mT and substrate temperature 500 °C. XRD revealed that thin film deposited at above said parameters was polycrystalline in nature with larger crystallite size (32 nm) and low dislocation density (0.97×10¹⁵ lines m⁻²). The deposited film also showed preferred orientation along (112) plane. The morphology of the film depicted by FE-SEM was compact and uniform without any micro cracks and pits. The deposited film exhibited good stoichiometry (Ga/In+Ga=0.19 and In/In+Ga=0.8) with desired Cu/In+Ga ratio (0.92), which is essential for high efficiency solar cells. Transmittance of deposited film was found to be very low (1.09%). The absorption coefficient of film was ~10⁵ cm⁻¹ for high energy photon. The band gap of CIGS thin film evaluated from transmission data was found to be 1.13 eV which is optimum for solar cell application. The electrical conductivity (7.87 Ω⁻¹ cm⁻¹) of deposited CIGS thin film at optimum parameters was also high enough for practical purpose.     

微量Co2+掺杂ZnO粉体的结构和光学性能研究

采用球磨法制备了Zn1-xCoxO(x=0,0.004,0.008)纳米粉体,分别利用XRD,PL光谱和紫外-可见吸收光谱对样品进行了表征。XRD图谱显示样品呈六方纤锌矿结构,随着Co2+离子掺杂量的增加,晶格常数和平均晶粒尺寸略有减小。在PL光谱上观察到三个发光带:370nm处的本征发光峰、468nm附近的强蓝光发光峰,以及533nm附近的绿光发光峰。和球磨样品相比,1 200℃退火的样品的发光强度明显增强,这归因于退火使样品晶粒长大。在紫外-可见吸收谱上可以观察到两个吸收带:由ZnO的带隙吸收引起的360～388nm的强紫外吸收带和由Co2+离子的d-d跃迁引起的565nm附近的可见光吸收带。因此通过调节Co2+掺杂量和选择适当的退火温度可制备高质量的发光材料。     

sol-gel 法制备ATO薄膜的结构与光学性能研究

采用sol-gel法在玻璃衬底上制备ATO(SnO2∶Sb)薄膜,并用XRD、SEM、紫外-可见光谱和光致发光对薄膜进行了表征,研究了ATO薄膜的结构和光学性能。结果表明:ATO薄膜微晶晶相与SnO2一致,仍然是四方金红石结构;ATO薄膜在可见光区的透过率超过80%,当r(Sb∶Sn)为0.15时,ATO薄膜的透过率最高达87%;ATO薄膜在344～380nm处有一个很强的紫外-紫光发射带,随着Sb掺杂量的增加,发射峰逐渐变强,在r(Sb∶Sn)为0.25时,发射峰相对强度达302.4。     

一种创新结构宽波段中红外空芯光纤的设计与研究

提出一种双包层结构Ge/GeO2介质膜空芯中红外光纤.先采用排布法拉制出包层带有多层空气孔的空芯毛细管,最外层涂有一层硅胶,以加强其机械强度,然后利用化学气相沉积和还原方法在空芯石英毛细管中制备出GeO2-Ge的多层介质反射膜,该膜层提高了Ge/GeO2膜层在短波段的反射效率.经光谱检测分析,该光纤可传输波长为3-12μm,并且中间没有出现大的吸收峰.     

The effects of water-to-alkoxide ratio on the properties of gels and sol-gel derived high Tc ceramic superconductors

Type II (Y₁Ba₂Cu₃O_6+k) superconductors have been fabricated via sol-gel processing. Cu(II) ethoxide, Ba-methoxyethoxide, and Y-methoxyethoxide were synthesized from high purity metals. Gels were formed by mixing metal alkoxides, water, and solvents. The water-to-metal alkoxide ratio was chosen to be 1:1, 2:1, and 4:1 which resulted in a sol-to-gel transition time ranging from two to five days. The dried gels were fired at 950° C in flowing oxygen for 15 hrs and then slowly cooled to room temperature. The microstructure of the superconductors consisted of several phases. Susceptibility vs temperature curves showed that both the transition temperature (78 to 83 K) and the sharpness of the paramagnetic to diamagnetic transition were affected by the water-to-metal alkoxide ratio.     

预填充聚苯乙烯控制SiO2/ZrO2薄膜膜间渗透

提出预填充方式控制膜间渗透,采用聚苯乙烯(PS)对低折射率SiO2膜内孔隙进行预填充,镀第2层ZrO2后再于甲苯中洗脱,恢复孔隙率以实现膜间防渗透。采用椭偏仪、紫外-可见光分光光度计、原子力显微镜(AFM)和光学显微镜对薄膜进行表征,研究了预填充PS前后的溶胶-凝胶SiO2/ZrO2薄膜膜间渗透与激光辐照损伤。结果表明,单层SiO2填充PS后膜面均方根粗糙度由4.164 nm下降为1.983 nm,折射率由1.1474增加到1.358 3,在甲苯中浸泡15 min后可完全清除PS。PS填充后的SiO2/ZrO2双层膜清洗1 h后,可使填充了PS的SiO2层的平均折射率由1.36降为1.29(未填充区域为1.38),透光率峰值提高(1～2)%。利用Nd:YAG激光器(1.064μm,8.1 ns)对SiO2/ZrO2双层膜进行了损伤阈值的测试,结果表明经PS填充并清洗后损伤阈值降低了8 J/cm2,但两者损伤形貌均为熔融型。     

sol-gel法制备的ZnO:(Al,La)透明导电膜光电性能

通过X射线衍射、紫外–可见分光光度计、扫描电镜和四探针仪分析等手段,考察了退火温度对ZnO:(Al,La)薄膜微观结构、光学和电学性能的影响,Al掺杂浓度对电阻率的影响。结果表明:随退火温度的升高,薄膜(002)晶面择优取向生长增强,平均晶粒尺寸增大,电阻率降低,透光率上升。在x(Al)为1%,退火温度550℃时,薄膜最低电阻率为1.78×10–3?·cm,平均透光率超过85%。