Study of elemental and phase composition of PZT thin films by auger depth profiling

The composition of PZT thin films deposited by diode HF sputtering of a ceramic target on Pt/Ti/SiO₂/Si substrates was studied. The remanent polarization of grown films was to 22 μC/cm². A technique for verifying the adequacy of elemental and phase composition of thin films to the ferroelectric phase composition was proposed. The problems of reliable contact of Pt electrodes with the PZT layer were considered.     

Spetroscopic ellipsometry study on electrical and elemental properties of Sb-doped ZnO thin films

Room-temperature spectroscopic ellipsometry data has been analyzed to determine the complex dielectric functions, ɛ(E) = ɛ₁(E) + iɛ₂(E) of as-deposited Sb-doped ZnO (SZO) thin films grown on n-Si(100) substrates by dual ion beam sputtering deposition system for different growth temperatures (T_g). The dielectric functions have been obtained from ellipsometry data analyses using Cody-Lorentz oscillator in the GenOsc model. A gradual reduction in the value of electron concentration and finally the conversion of doping characteristics from donor type to acceptor type was observed with the rise in T_g. This, in turn, resulted in the decline of broadening of ɛ₁ peaks, and hence in the increase of excitonic lifetime. Optical band-gap energy was observed to decrease with increase in T_g from 200 to 300 °C, and then rise continuously with further increase in T_g. X-ray diffraction measurements showed that all SZO films had (002) preferred crystal orientation. Hall measurement and X-ray photoelectron spectroscopy analysis confirmed that the change in the electrical conduction from n-to p-type was due to the enhancement in the value of Sb⁵⁺/Sb³⁺ ratio and Sb_Zn–2V_Zn complex formation in SZO films.     

Numerical simulation of nonlinear properties of fullerene-containing one-dimensional photonic crystal

A model of interaction between a one-dimensional photonic crystal (PC) containing a defect (nonlinear optical layer of C₆₀ fullerene) and radiation with a wavelength ??₀= 1064 nm under steady-state conditions has been considered. This structure is a Fabry-Perot microcavity: a fullerene layer (with a thickness multiple of ??₀/2) is placed between the interference mirrors formed by alternating layers ??₀/4 thick. The PC under consideration (1) has a narrow transmission band in the vicinity of ??₀ against the background of a relatively wide 100%-reflection band (photonic band gap) in the linear mode and (2) provides multiple amplification of the radiation intensity in the intermediate layer with respect to the external radiation intensity. Since C₆₀ fullerene exhibits a significant optical Kerr nonlinearity, the optical thickness of the intermediate layer under irradiation deviates from the value multiple of ??₀/2; as a result, 100% transmission for ??₀ changes to almost 100% reflection at a certain radiation intensity. Thus, this structure behaves as a peculiar optical limiter.     

Optical and electrical properties of swift heavy ion beam-irradiated polycarbonate/polystyrene bilayer films

Polycarbonate/polystyrene bilayer films prepared by solvent-casting method were irradiated with 55 MeV carbon ion beam at different fluences ranging from 1×10¹¹ to 1×10¹³ ions cm^?2. The structural, optical, surface morphology and dielectric properties of these films were investigated by X-ray diffraction (XRD), UV–visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, optical microscopy and dielectric measurements. The XRD pattern shows that the percentage of crystallinity decreases while inter-chain separations increase with ion fluence. UV–visible spectroscopy shows that the energy band gap decreases and the number of carbon atoms in nanoclusters increase with the increase in ion fluences. The refractive index is also found to decrease with the increase in the ion fluence. Optical microscopy shows that after irradiation polymeric bilayer films color changes with ion fluences. The FTIR spectra evidenced a very small change in cross-linking and chain scissoring at high fluence. Dielectric constant decreases while dielectric loss and AC conductivity increase with ion fluences.     

氘代聚合物膜靶制备技术与性能研究

 氘代聚合物膜是快点火基础物理实验的一种重要靶型。通过氘代苯乙烯单体的本体自由基聚合反应制备氘代聚苯乙烯，并利用流延法和浇铸法制备出厚度从几十nm到数百μm的膜靶。溶剂挥发过程中的随机扰动对膜厚均匀性造成影响，采用清洁的基片和在涂沫基片或模具外加防护罩可以降低这种影响。采用PVA作脱膜剂有利于获得较薄的聚合物薄膜。DSC分析表明薄膜的玻璃化转变温度与热处理过程有关，缓慢退火有利于提高Ｔ-g和储能模量。     

Dynamic holograms recording in fullerene-containing solid-state matrices: Porous glass slides and PMMA films

Fullerene-containing solid-state matrices were studied theoretically and experimentally as the active material for all-optical switching devices. Dynamics hologram recording and spectral analysis were used to study temporal stability and efficiency of nonlinear response of the media. Porous glass and polymethylmethacrylate hosts were utilized as C₆₀-containing matrices. Experiments were carried out using nano- and picosecond laser radiation with wavelength 532 nm.     

Surface composition and electronic properties of indium tin oxide and oxynitride films

The surface properties of indium tin oxynitride films prepared by rf-sputtering in nitrogen atmosphere were investigated by X-ray and ultraviolet photoelectron spectroscopy as well as electron energy loss spectroscopy and Auger electron spectroscopy depth profiling. The results are compared to reference measurements on conventional rf-sputtered indium tin oxide films. The incorporated nitrogen is present in different chemical environments. Employing these different spectroscopic techniques, it was found that desorption of nitrogen from the ITON structure upon annealing is the origin of the observed drastical changes in the surface composition and electronic structure. The formation of oxygen vacancies and Sn surface segregation upon annealing is linked to improvements in the physical properties (larger spectral range of transmittance and higher conductivity) of the films.     

Physical properties of ZnSe thin films deposited on glass and silicon substrates

ZnSe thin films were deposited onto Corning glass and silicon substrates using thermal evaporation. The samples were prepared at different substrate temperatures. The thin films’ surface chemical composition was determined through Auger electron spectroscopy (AES). AES signals corresponding to Zn and Se were only detected in AES spectra. The samples’ crystallographic structure was studied through X-ray diffraction. The material crystallised in the cubic structure with preferential orientation (111). Optical properties of the ZnSe films were studied over two energy ranges via electron energy loss spectroscopy (10–90 eV) and spectral transmittance measurements (0.4–4 eV). In both cases, the spectral variation of the refractive index and the absorption coefficient were determined by fitting the experimental results with well-established theoretical models. Experimental values for the material’s gap were also found, and photoconductivity (PC) measurements were carried out. Transitions between bands, usually labelled Γ^V₈ → Γ^C₆ and Γ^V₇ → Γ^C₆, were found in the optical and PC responses. A wide spectral photoconductive response between 300 and 850 nm was found in the ZnSe/Si samples prepared at 250 °C substrate temperature.     

Substrate-dependent structure, microstructure, composition and properties of nanostructured TiN films

Titanium nitride films of a thickness of ∼1.5 μm were deposited on amorphous and crystalline substrates by DC reactive magnetron sputtering at ambient temperature with 100% nitrogen in the sputter gas. The growth of nanostructured, i.e. crystalline nano-grain sized, films at ambient temperature is demonstrated. The microstructure of the films grown on crystalline substrates reveals a larger grain size/crystallite size than that of the films deposited on amorphous substrates. Specular reflectance measurements on films deposited on different substrates indicate that the position of the Ti-N 2s band at 2.33 eV is substrate-dependent, indicating substrate-mediated stoichiometry. This clearly demonstrates that not only structure and microstructure, but also chemical composition of the films is substrate-influenced. The films deposited on amorphous substrates display lower hardness and modulus values than the films deposited on crystalline substrates, with the highest value of hardness being 19 GPa on a lanthanum aluminate substrate.     

Physical and electrochemical properties of Li-intercalated Sn oxide films made by sputtering

Sn oxide films were made by reactive rf magnetron sputtering under conditions that led to both electronic and ionic conductivity. The film structure was studied by X-ray diffraction and Atomic Force Microscopy (AFM). Li⁺ intercalation produced electrochromism with coloration efficiency peaked in the infrared. Cyclic voltammograms taken at different sweep rates were interpreted in terms of a unique structural parameter related to the fractal dimension of a self-affine surface relief and in excellent agreement with the fractal dimension as obtained with AFM. Mössbauer spectroscopy was used to determine the valence state of the Sn-atoms; a change from Sn⁴⁺ to Sn²⁺ was detected after electrochemical intercalation of Li⁺.     

聚苯乙烯的氘化及其性能研究

采用聚苯乙烯(PS)催化氘化技术,在使苯环被氘化饱和的基础上,成功地制备出了部分氘化的聚环己基乙烯（D-PVCH,C8H8D6）。用傅里叶红外光谱仪、核磁共振仪对D-PVCH的结构进行了表征,结果表明与目标产物吻合,即苯环被氘饱和转化为环己基,氘代率为41.5%。采用差式扫描量热仪和热重分析仪分析了D-PVCH的热性能,结果表明D-PVCH的玻璃化转变温度为125 ℃,5%失重温度为403 ℃。另外,D-PVCH可溶于常见溶剂,如石油醚、环己烷和甲苯等。与PS相比,D-PVCH具有较好的热稳定性和良好的溶解性能。     

聚苯乙烯的氘化及其性能研究

采用聚苯乙烯(PS)催化氘化技术,在使苯环被氘化饱和的基础上,成功地制备出了部分氘化的聚环己基乙烯（D-PVCH,C8H8D6）。用傅里叶红外光谱仪、核磁共振仪对D-PVCH的结构进行了表征,结果表明与目标产物吻合,即苯环被氘饱和转化为环己基,氘代率为41.5%。采用差式扫描量热仪和热重分析仪分析了D-PVCH的热性能,结果表明D-PVCH的玻璃化转变温度为125 ℃,5%失重温度为403 ℃。另外,D-PVCH可溶于常见溶剂,如石油醚、环己烷和甲苯等。与PS相比,D-PVCH具有较好的热稳定性和良好的溶解性能。     

Phase organization of solvent-crystallized syndiotactic polystyrene films

Sorption and diffusion of dichloromethane vapor in the helical forms—that is, δ and γ—of syndiotactic polystyrene were investigated. The thermal transition from the δ to the γ form occurs through an intermediate mesomorphic form, also characterized by chains in helical conformation but lacking true crystalline order. The mesomorphic phase was found impermeable to the vapor at low activity, becoming permeable at higher activities. The presence of a mesomorphic phase, along with the crystalline and the amorphous forms, was suggested in the crystallized samples, too, and its fraction increases greatly going from the δ to the γ form.     

Physical properties of ZnS thin films prepared by chemical bath deposition

Zinc sulphide thin films are deposited on SnO₂/glass using the chemical bath deposition technique. X-ray diffraction and atomic force microscopy are used to characterize the structure of the films; the surface composition of the films is studied by Auger electrons spectroscopy, the work function and the photovoltage are investigated by the Kelvin method. Using these techniques, we specify the effect of pH solution and heat treatment in vacuum at 500 °C. The cubic structure corresponding to the (1 1 1) planes of β-ZnS is obtained for pH equal to 10. The work function (Φ_material − Φ_probe) for ZnS deposited at pH 10 is equal to −152 meV. Annealing at 500 °C increases Φ_m (by about 43 meV) and induces the formation of a negative surface barrier. In all cases, Auger spectra indicate that the surface composition of zinc sulphide thin films exhibits the presence of the constituent elements Zn and S as well as C and O as impurity elements.     

Physical properties of ZnO thin films deposited by spray pyrolysis technique

Thin films of ZnO have been prepared on glass substrates at different thicknesses by spray pyrolysis technique using 0.2 M aqueous solution of zinc acetate. X-ray diffraction reveals that the films are polycrystalline in nature having hexagonal wurtzite type crystal structure. The resistivity at room temperature is of the order 10⁻² Ω cm and decreased as the temperature increased. Films are highly transparent in the visible region. The dependence of the refractive index, n, and extinction coefficient, k, on the wavelength for a sprayed film is also reported. Optical bandgap, E_g, has been reported for the films. A shift from E_g = 3.21 eV to 3.31 eV has been observed for deposited films.     

Specific features of holographic recording of diffraction gratings in thin films of fullerene-containing organic systems

Thin films based on fullerene-containing polyimides COANP and PNP were studied using methods of dynamic holography under conditions of Raman-Nath diffraction. A significant increase in the diffraction efficiency of the fullerene-containing samples was detected, and the threshold of the transition from phase grating to amplitude grating was determined. The qualitative explanation of the results is based on the spectral features and the thermal properties of the systems under study.     

SrF2-CaF2混合物薄膜的物理及红外光学特性研究

采用热蒸发和电子束蒸发两种沉积方式分别沉积了相同厚度的SrF₂-CaF₂ (比例为1∶1) 的混合物薄膜,对其物理和光学特性进行了研究,并定量地给出了其在红外波段的光学常数,填补了这一数据的空白. 同时提供了一种获得不同低折射率薄膜的方法.文中还以该比例的混合物作为低折射率材料,研制出具有很好的光学性能的长波红外宽光谱增透膜. 关键词： 2-CaF₂混合物薄膜')" href="#">SrF₂-CaF₂混合物薄膜 表面形貌 红外光学特性 宽光谱增透膜     

Physical and chemical properties of nanostructured CoO-AlOx granular films

A series of nano CoO-AlO_x granular films were prepared by Ar-O₂ reactive rf sputtering and their resistive and magnetoresistive properties were measured for studying the spin-dependent properties. Transmission electron microscopy and X-ray photoelectron spectroscopy are also utilized to investigate the structures and chemical states of these samples. Based on our results, the particles of CoO with radius around 2 nm could be magnetic at room temperature and provide a large tunneling magnetoreststance of −6% through the AlO_x barrier.