Study of phase separation in Ga25Se75 xTex chalcogenide thin films

The effects of composition and thermal annealing in between glass transition and crystallization temperature on the optical and structural properties of Ga25Se75-xTex were investigated. The glass transition and crystallization temperature of the synthesized samples was measured by non-isothermal DSC measurements. Amorphous thin films of Ga25Se75-xTex glasses were grown onto ultra clean glass/Si wafer (100) substrates using the vacuum evaporation technique. The effect of thermal annealing on the optical gap (Eg) for Ga25Se75-xTex thin films in the temperature range 358-388K is studied. As-prepared and annealed thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and optical absorption. Thermal annealing was found to be accompanied by structural effects, which in turn, lead to changes in the optical constants. The optical absorption coefficient (a) for as-deposited and thermally annealed films was calculated from the absorbance data. From the knowledge of absorption coefficient at different wavelengths, the optical band gap (Eg) was calculated for all compositions of Ga25Se75-xTex thin films before and after thermal annealing. Results indicate that allowed indirect optical transition is predominated in as-deposited and thermally annealed thin films. The influence of Te incorporation and thermal annealing in Ga25Se75-xTex thin films results in a gradual decrease in the indirect optical gap, this behaviorcan be explained as increased tailing. The decrease in optical band gap and an increase in absorption coefficient and extinction coefficient with thermal annealing can be attributed to transformation from amorphous to crystalline phase.     

Structural and optical properties of Cr doped ZnO crystalline thin films deposited by reactive electron beam evaporation technique

ZnO and Cr-doped ZnO thin films are grown on to glass substrates using reactive electron beam(e-beam) evaporation technique.Variation of structural,morphological,and optical properties with Cr doping is investigated.X-ray diffraction(XRD) studies show that the films are polycrystalline in nature with single phase.Energy dispersive spectroscopy(EDS) results demonstrate that Cr ions are substitutionally incorporated into ZnO.Atomic force microscopy(AFM) reveals that the films present a compact surface and root mean squared(RMS) roughness increased with Cr contents.The optical band gap energy Eg of the films has been determined using Transmission data by spectrophotometer and ellipsometry.The band gap energy found to be decreased with increasing Cr doping concentration.The optical constants(refractive index,extinction coefficient) are calculated using ellipsometry and found to increase with Cr doping concentration.     

衬底偏压对ZnO：Zr薄膜结构及光电性能的影响

以Zn：Zr（Zr片贴在金属Zn靶上面）为溅射靶材,利用直流反应磁控溅射法在Ar／O_2混合气氛中制备Zr掺杂ZnO（ZnO：Zr）薄膜．在制备ZnO：Zr薄膜时,衬底偏压在0～60V之间变化．研究结果表明,衬底偏压对薄膜的结构、光学及电学性能有很大影响．当衬底偏压从0增大到60V时,薄膜的平均光学透过率和平均折射率都单调增大,而薄膜的晶粒尺寸先增大后减小．ZnO：Zr薄膜电阻率的变化规律与晶粒尺寸相反．     

Mg掺杂ZnO薄膜的结构和光学性质

采用磁控溅射方法在硅和石英衬底上制备了纯ZnO和Mg0.04Zn0.96O薄膜.用XRD和AFM表征薄膜的晶化行为和显微结构,用透射谱和光致发光谱分析薄膜的光学性质.分析结果显示:两种薄膜均为六角纤锌矿结构,且沿c轴取向,薄膜表面光滑致密,晶粒分布均匀;薄膜在可见光范围内具有较高的透过率,Mg掺杂后透射谱吸收边向高能侧移动,相应的薄膜的带隙宽度从3.28 eV升至3.36 eV;用包络法计算出薄膜的光学常数表明,Mg掺杂没有明显改变薄膜的折射率,但使消光系数明显增大;薄膜的光致发光谱分析也发现,掺入Mg使带边发射峰蓝移.     

掺杂与应力对ZrO2薄膜电子结构和光学性质的影响

利用基于密度泛函理论的第一性原理平面波超软赝势方法系统地研究了掺杂和应力对ZrO_2薄膜的电子结构与光学性质的影响.本文首先研究了Hf原子替代掺杂对ZrO_2薄膜物性的影响,研究结果表明,Hf原子掺杂减小了ZrO_2薄膜的带隙和态密度大小,可在一定程度上降低其表面缺陷电荷和漏电流.掺杂Hf原子后介电峰和吸收峰的值明显下降,同时介电峰和吸收峰的波形均出现了窄化现象,半高宽显著减小.本文也着重研究了不同应力下四方晶相ZrO_2薄膜物理性质变化及规律.研究发现压应力显著调控了ZrO_2薄膜的带隙以及价带顶和导带底附近的能带结构.施加应力后吸收峰的吸收范围和强度均显著增大,峰值对应的光子能量蓝移则表明对紫外光的吸收随着应力的增加有所增强.在低能量红外和可见光区域,施加压应力后ZrO_2薄膜的折射率变大,但在紫外线区域,压应力使ZrO_2薄膜的折射率呈现出先增大后减小的波动特性.上述研究结果为ZrO_2薄膜材料的设计与应用提供了理论依据.     

沉积电位对ZnO薄膜结构及光电性能的影响

以硝酸锌溶液为电解液,采用电化学沉积方法,在导电玻璃(ITO)上制备ZnO薄膜.使用X射线衍射仪、扫描电子显微镜对制备的ZnO薄膜结构和形貌进行表征,并研究薄膜的光电性能.结果表明,通过该方法制备的ZnO具有标准的六方纤锌矿纳米柱状结构,沉积电位为-0.75、-0.80、-0.85 V时,制备的ZnO纳米柱的直径分别为250、400、500 nm,禁带宽度分别为3.12、3.27、3.29 eV,光电流密度分别为1.18、1.07、0.89μA.cm-2.     

氮气分压比对硼碳氮薄膜的组分及光学带隙的影响

采用射频磁控溅射方法以不同的氮气分压比(1/10～2/3)制备出一组硼碳氮薄膜.傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)测量发现样品的组成原子之间均实现了原子级化合.XPS测量结果表明,所有样品中的B、N原子比近似为1:1,其化学配比为BCx N(0.16＜x＜1.46).紫外/可见/近红外分光光度计用于测量样品的吸收光谱.由吸收谱线在低能区域(2.0～3.0 eV)的光吸收,利用关系作图法求出光学带隙Eopt范围为0.17～0.83 eV.氮气分压比对薄膜的组分和光学带隙有很大影响,其通过改变薄膜组分而影响光学带隙,并且碳原子数小的样品具有较宽的光学带隙.以氮气分压比为1/3条件下制备的样品中碳原子数最小,它的光学带隙最宽为0.83 eV.     

CHF3／DMCPS比对F掺杂SiCOH薄膜结构及性能的影响

研究了用十甲基环五硅氧烷和三氟甲烷电子回旋共振等离子体沉积的掺FSiCOH低k薄膜中，CHF，／DMCPS比对薄膜结构、成分、介电性能、热稳定性和憎水性的影响．结果表明，随着CHF，／DMCPS比的增大，沉积的薄膜从SiCOH向F-SiCOH和a—C：F：H转变．对于F-SiCOH薄膜，在获得较低介电常数的前提下，薄膜热稳定性和憎水性得到改善．     

Corrosion resistance and thermal stability of sputtered Fe44Al34Ti7N15 and Al61Ti11N28 thin films for prospective application in oil and gas industry

Fe-and Al-based thin-film metallic glass coatings (Fe₄₄Al₃₄Ti₇N₁₅ and Al₆₁Ti₁₁N₂₈) were fabricated using magnetron co-sputtering technique, and their corrosion performances compared against wrought 316L stainless steel. The results of GI-XRD and XPS analyses demonstrated amorphous structure and oxide layer formation on the surface of the fabricated thin films, respectively. The potentiodynamic (PD) polarization test in chloride-thiosulfate (NH₄Cl ​+ ​Na₂S₂O₃) solution revealed lower corrosion current (I_corr) (0.42 ​± ​0.02 ​μA/cm² and 0.086 ​± ​0.001 ​μA/cm² Vs. 0.76 ​± ​0.05 ​μA/cm²), lower passivation current (I_pass) (1.45 ​± ​0.03 ​μA/cm² and 1.83 ​± ​0.07 ​μA/cm² Vs. 1.98 ​± ​0.04 ​μA/cm²), and approximately six-fold higher breakdown potential (E_bd) for Fe- and Al-based coatings than those of wrought 316L stainless steel. Electrochemical Impedance Spectroscopy (EIS) of both films showed 4- and 2-fold higher charge transfer resistance (R_ct), 7- and 2.5-times higher film resistance (R_f), lower film capacitance values (Q_f) (10 ​± ​2.4 ​μS-s^acm^-2, and 5.41 ​± ​0.8 ​μS-s^acm^-2 Vs. 18 ​± ​2.21 ​μS-s^acm^-2), and lower double-layer capacitance values (Q_dl) (31.33 ​± ​4.74 ​μS-s^acm^-2, and 15.3 ​± ​0.48 ​μS-s^acm^-2 Vs. 43 ​± ​4.23 ​μS-s^acm^-2), indicating higher corrosion resistance of the thin films. Cyclic Voltammetry (CV) scan exhibited that the passive films formed on the Fe- and Al-based coatings were more stable and less prone to pitting corrosion than the wrought 316L stainless steel. The surface morphology of both films via SEM endorsed the CV scan results, showing better resistance to pitting corrosion. Furthermore, the thermal analysis via TGA and DSC revealed the excellent thermal stability of the thin films over a wide temperature range typically observed in oil-gas industries.     

用RF—PECVD制备的SnO2薄膜光电性质及化学成分

利用ＸＰＳ研究了ＲＦ－ＰＥＣＶＤ制备ＳｎＯ２薄膜的化学计量配比，测试了ＳｎＯ２薄膜的光学和电加热特性。结果表明：具有导电性能的ＳｎＯ２薄膜是一种非理想化学计量配比的氧化物半导体薄膜材料，薄膜还具有较高的可见光透过率和较好的电加热性能。     

SnO_2薄膜的形貌及其电特性分析

我们用ＰＥＣＶＤ方法制备出ＳｎＯ_２薄膜，透射电镜ＴＥＭ分析表明沉积温度由高到低时，ＳｎＯ_２膜从多晶态转变为非晶态，并且其电阻率随之增加；沉积时氧气流量增加时，ＳｎＯ_２的电阻率增加。     

Nd掺杂BST薄膜的微结构与光学特性研究

用改进的溶胶-凝胶技术,在硅和石英衬底上制备了不同浓度的Nd掺杂Ba0.80Sr0.20TiO3薄膜,应用XRD和SEM表征了薄膜的晶化行为和微观形貌.测试发现700℃退火后,薄膜晶化情况良好,具有典型的多晶钙钛矿结构,表面致密,无裂纹和孔洞,晶粒生长均匀,随着Nd掺杂量的增加,晶粒尺寸逐渐减小.在200~1 000 nm的波长范围内测试了薄膜的透射谱,用"包络法"计算了薄膜的折射率,薄膜折射率与波长呈现典型的电子带间跃迁的色散关系,波长为400 nm时,1%Nd(按物质的量计算百分比)掺杂的BST薄膜的折射率为2.06,小于纯BST薄膜的折射率2.10,这是由于Nd掺杂引起薄膜内部应力变化造成薄膜折射率降低.由吸收谱和Tauc关系确定了Nd掺杂对薄膜的光学带隙的影响.     

沉积温度对TiN/SiN_x多层膜结构及力学性能的影响

采用反应磁控溅射方法,在不同沉积温度条件下制备了一系列多晶TiN/SiNx纳米多层膜,并用X射线衍射仪（XRD）、X射线反射仪（XRR）及纳米压痕仪（Nanoindenter）表征了材料的微观结构及力学性能。结果表明,沉积温度对多层膜的界面结构、择优取向及力学性能有显著影响：当沉积温度为室温时,多层膜的界面较高温条件下粗糙;而多层膜的择优取向在沉积温度为400℃时呈现强烈的TiN（200）织构;多层膜的硬度及弹性模量在室温至400℃温度范围内变化不大。     

热处理对ITO薄膜光电性能和抗蚀刻性的影响

利用不同的热处理温度对磁控溅射在玻璃基底的ITO薄膜进行退火处理.借助于原子力显微镜(AFM)、分光辐射计、四探针电阻测试仪等测试手段对不同热处理后的ITO薄膜样品进行表征,研究了不同热处理温度对ITO薄膜表面形貌、面电阻、透光率及抗刻蚀性能的影响.结果表明,随着退火温度的升高,ITO薄膜表面粗糙度增加,面电阻增大,在可见光区的透光率变大,耐刻蚀性增强.     

Influence of growth conditions on the electrochemical synthesis of SnS thin films and their optical properties

Tin sulfide (SnS) thin films were prepared by electrodeposition onto fluorine-doped tin oxide (FTO) glass substrates using an aqueous solution containing SnCl₂ and Na₂S₂O₃ at various deposition potentials (E) and bath concentrations. The pH value and temperature of the solution were kept constant. The deposited films were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), photoluminescence (PL), and ultraviolet–visible (UV–Vis) spectroscopy. The FESEM images demonstrated that changes in the deposition potential (E) and solution concentration led to marked changes in the morphology of the deposited SnS films. Energy-dispersive X-ray analysis (EDXA) results showed that the Sn/S atomic ratio strongly depended on both the solution concentration and the deposition potential. To obtain an Sn/S atomic ratio approximately equal to 1, the optimal Sn2+/S₂O₃2- molar ratio and E parameter were 1/8 and -1.0 V, respectively. The XRD patterns showed that the synthesized SnS was obviously polycrystalline, with an orthorhombic structure. The effects of the variations of bath concentration and deposition potential on the band-gap energy (E_g) were studied using PL and UV–Vis experiments. The PL spectra of all the SnS films contained two peaks in the visible region and one peak in the infrared (IR) region. The UV–Vis spectra showed that the optical band-gap energy varies from 1.21 to 1.44 eV.     

衬底温度对ZnO：Al薄膜结构和光透过性能的影响

利用超声喷雾热解方法以不同的沉积温度（450～530℃）在石英衬底上制备出具备较高光学质量的ZnO：Al（AZO）薄膜.通过X射线衍射谱（XRD）研究了薄膜的结构,用扫描电子显微镜（SEM）研究了薄膜的表面形貌,用紫外可见（UV）分光光度计对薄膜的光透过特性进行了测试分析.结果表明：所制备薄膜在可见波段具有较高透过率,并且沉积温度对AZO薄膜的结构和光透过性能有很大影响.在衬底温度为470℃时得到的AZO薄膜具有（002）择优取向,结晶质量最好、光透过率最高,在可见光区平均透过率达到85%以上.     

Growth, structural, optical, thermal and dielectric properties of a novel semi-organic nonline ar optical crystal: Dichloro-diglycine zinc II

Dichloro-diglycine zinc II(DCDGZ II),a semi-organic nonlinear optical material has been synthesized and single crystals were grown from the aqueous solution up to dimensions 20×10×3 mm3.The title compound,DCDGZ II(C4H10Cl2N2O4Zn H2O) crystallizes into monoclinic structure with the space group of C2/c.The unit-cell parameters were found to be a=14.4191(7),b=6.9180(2),c=12.9452(6) and Z=4.In the crystal structure,DCDGZ II layer is building up alternatingly with layers of water in which the zinc ions lie on a twofold axis.Theoretical calculations for polarizability,which are useful for device fabrication were made using Clausius–Mosotti equation and Penn analysis and the results were compared.Fourier transform infrared(FTIR) spectroscopic studies were performed for the identification of the different functional groups presented in the compound.The UV–vis–NIR absorption spectrum reveals that the lower UV cut-off wavelength is 240 nm.The optical band gap of the crystal was estimated as 2.2 eV.The surface morphology,thermal behaviour,dielectric properties have been studied using SEM,TG/DTA and LCR HITESTER analyzer.The nonlinear optical property of the crystal was also confirmed using Kurtz powder technique.     

Influence of Al doping on the crystal structure,optical properties,and photodetecting performance of ZnO film

The structural,optical,and electrical properties of undoped and Al-doped ZnO films deposited on p-Si(001)substrate were studied using DC-unbalanced magnetron sputtering.This study is motivated by the absence of detail reports concerning the orbital states inducing the optical bandgap(E_g) blueshift.Besides,the influences of Al on the possible modification of point defect and the photodetecting performance are highlighted to offer guidelines for better development in ZnO-based photodetector.It was found that the Al doping reduced the grain size.The doping increased the lattice parameters and slightly decreased the local-symmetry distortion at ZnO_4.From the absorbance spectra,the doping increased Eg of ZnO film(3.28-3.36 eV),induced by the Burstein-Moss effect.From the density-functional calculation,the Burstein-Moss effect induced E_g from the valence band maximum(VBM) to Fermi level located above the lowest Zn 4s conduction state.From the photoluminescence spectra,the undoped film showed the transitions from O vacancy,Zn interstitial,and free-exciton states to the VBM.The doped film showed the transitions from Zn interstitial to O interstitial and few Zn vacancy states at the cost of O vacancies.Moreover,the energy level of free-exciton states slightly decreased.Notably,O interstitials increased the lattice parameters.From the electrical properties,the doping enhanced the ultraviolet-region photo-to-dark-current ratio up to 3.044 V,leading to the photodetecting sensitivity enhancement.This study emphasizes the significant effect of Al doping on the optical absorbance,point-defect evolution,and photodetecting performance of ZnO film for low-voltage ultraviolet photodetector applications.     

Mn掺杂对Ba0.5Sr0.5TiO3薄膜介电性能的影响

以醋酸盐和钛酸四丁酯为原料,采用溶胶-凝胶工艺在Pt／TiO2／SiO2／Si基片上制备了掺锰Ba0.5Sr0.5TiO3薄膜。通过X射线衍射和扫描电镜分析研究了薄膜的相结构和形貌,测试了以Pt为底电极、Ag为上电极的MFM电容器的介电性能。研究结果表明：掺锰Ba0.5Sr0.5TiO3薄膜较未掺杂的Ba0．5Sr0．5TiO3薄膜介电常数高、介电损耗降低。介温谱表明在居里温度附近发生弥散型相变,且居里温度有向低温方向漂移的趋势。     

Influence of catalyst on structural and morphological properties of TiO2 nanostructured films prepared by sol–gel on glass

Transparent TiO2 thin films have been prepared by the sol-gel method using titanium alkoxides as precursors.Thin films were deposited on glass supports by the dip-coating technique.The TiO2 layer acts as a self-cleaning coating generated from its photocatalysis and photoinduced superhydrophilicity.The crystalline structure of TiO2 films was dominantly identified as the anatase phase,consisted of uniform spherical particles of about 14-50 nm in size,which strongly depends upon catalyst-type and heat treatment temperature.Increasing heat treating temperature can lead to an increase in crystalline size.The results indicated that the sample S.S(sample derived from sol containing sulfuric acid as catalyst) exhibits superhydrophilic nature and better photocatalytic activity,which can be attributed to its higher anatase content and lower crystalline size.Morphological studies,carried out using Atomic Force Microscopy(AFM),confirm the presence of crystalline phase with such a grain size and low surface roughness.Thus,the applied films exhibiting high photocatalytic activity,superhydrophilic behavior,and low surface roughness can be used as an efficient self-cleaning coating on glass and other optical applications.