Synthesis of P-type transparent conducting silver:indium oxide (AIO) thin films by reactive electron beam evaporation technique

Present paper reports the synthesis, electrical and optical properties of p-type conducting and transparent silver indium oxide (AIO) thin films prepared on glass substrates by reactive electron beam evaporation technique at three substrate temperatures (50, 200 and 250 °C) and at five evaporation rates (0.05 to 16.0 nm/s). The source material is pure powders of Ag₂O:In₂O₃=50:50 mol%. The AIO films are amorphous. The films, though not corresponding to Delafossite crystal structure, exhibit p-type conductivity, when prepared at an evaporation rate of 0.05 nm/s at all the three substrate temperatures. With increasing filament current, it is observed that (i) the electrical resistivity decreases and (ii) the refractive index of the films (at 632.8 nm, and is in the range: 1.219-1.211) decreases. The work function (effective Fermi level) has been measured on these samples by Kelvin Probe method. The results are explained on the basis of partial ionic charge and localization of covalent bonds in the AIO thin films.     

Room temperature photoluminescence property of Mo-doped In2O3 thin films

Mo-doped In₂O₃ thin films have been prepared on glass substrates using an activated reactive evaporation method and systematically studied the effect of oxygen partial pressure on the structural, optical, electrical and photoluminescence properties of the films. The obtained films are highly transparent and conductive. The films exhibited the lowest electrical resistivity of 5.2 × 10⁻⁴ Ω cm, with an average optical transmittance of 90% in the visible region. An intensive photoluminescence emission peaks were observed at 415 and 440 nm.     

Optical and electrical properties of C60Tex films

The structure, composition, and electrical and optical properties of thin tellurium-intercalated fullerene films C₆₀Te_x are investigated. The samples of compositions from C₆₀Te_0.1 to C₆₀Te₆ are prepared by thermal evaporation. The sample composition and the impurity distribution are controlled by the Rutherford backscattering technique. The Raman vibrational spectra indicate changes in the symmetry of a C₆₀ molecule: the strain of the molecule increases with a decrease in the tellurium concentration and decreases as the tellurium impurity concentration increases. The evolution of the optical absorption spectra and the electrical conductivity suggests that intercalation of a tellurium impurity leads to modification of the electronic structure of the material. This process is accompanied by a shift and change in shape of the optical absorption edge and a change in the electrical conductivity of films by several orders of magnitude depending on the composition. The electrical conductivity is minimum at a low tellurium impurity content.     

Effects of thermal annealing on titanium oxide films prepared by ion-assisted deposition

Titanium oxide thin films are prepared at a substrate temperature of 250 °C by electron-beam evaporation and ionassisted deposition. The effects of thermal annealing temperatures from 100 to 450 °C on the optical and mechanical properties are studied. The optical and mechanical properties include refractive indices, extinction coefficients, residual stress, surface roughness and crystallization. Experimental results show these properties of titanium oxide films clearly depend on the thermal annealing process.     

Effect of annealing on the optical and electrical properties of ZnO:Er films

The effect of dopant concentration and annealing in the oxidizing atmosphere on the structural, optical, and electrical properties of ZnO:Er films deposited on sapphire substrates by the electron-beam evaporation method is investigated. The optical and electrical properties of these films were studied by UV-VIS-IR absorption and reflection spectroscopy, photoluminescence, and resistivity measurements. Experimental results reveal that as-deposited ZnO:Er films have both high transmittance in the visible range and low electrical resistivity and can be used as efficient transparent conducting oxides (TCOs). These films annealed in the oxidizing atmosphere have a visible emission band which can be used to fabricate light-emitting diodes.     

Hydrogenation effect on electrical,optical and magnetic properties of ZnSe/Co bilayer DMS thin films

This paper reports ZnSe/Co bilayer diluted magnetic semiconductor thin films have been prepared by using thermal evaporation technique. The bilayer DMS thin films were hydrogenated at different pressures (15–45 psi) for a constant time of 30 min. Before and after hydrogenations of these bilayer thin films the electrical, optical and magnetic properties have been investigated. Electrical resistivity and optical band gap were found to be increased with respect to hydrogenation pressure. X-ray diffraction (XRD) and magnetic measurements confirmed the formation of DMS ZnSe/Co bilayer DMS thin films. Raman spectra show the presence of hydrogen in these thin films. Surface topography study of as-grown, annealed and hydrogenated ZnSe/Co bilayer thin films indicates uniform deposition, mixing of layers and increment in roughness at the surface due to hydrogen passivation effect respectively.     

Optical and electrical properties of SnO2:Sb thin films deposited by oblique angle deposition

The antimony doped tin oxide (SnO₂:Sb) (ATO) thin films were prepared by oblique angle electron beam evaporation technique. X-ray diffraction, field emission scanning electron microscopy, UV-vis-NIR spectrophotometer and four-point probe resistor were employed to characterize the structure, morphology, optical and electrical properties. The results show that oblique angle deposition ATO thin films with tilted columns structure are anisotropic. The in-plane birefringence of optical anisotropy is up to 0.035 at α = 70°, which means that it is suitable as wave plate and polarizer. The electrical anisotropy of sheet resistance shows that the sheet resistance parallel to the deposition plane is larger than that perpendicular to the deposition plane and it can be changed from 900 Ω/□ to 3500 Ω/□ for deposition angle from 40° to 85°, which means that the sheet resistance can be effectively tuned by changing the deposition angle. Additionally, the sandwich structure of SiO₂ buffer layer plus normal ATO films and oblique angle deposition ATO films can reduce the resistance, which can balance the optical and electrical anisotropy. It is suggested that oblique angle deposition ATO thin films can be used as transparent conductive thin films in solar cell, anti-foggy windows and multifunctional carrier in liquid crystal display.     

Effects of annealing on structural,optical and electrical properties of Al-doped ZnO thin films

Transparent conducting oxide (TCO) thin films such as SnO2, In2O3, and Cd2SnO4, have been used extensively as sensor devices, surface acoustic wave devices, coating to heat glass windows and transparent electrodes for solid state display devices, solar cells[1,2] because of their high optical transparency in the visible range, infrared reflec-tance and low d.c. resistivity. Although SnO2 film was developed early, nowadays Sn-doped In2O3 (ITO) films are the predominant TCO thin film in …     

Influence of γ-irradiation on the optical and electrical properties of Se(0.85) Te(0.15) films

Abstract

Se_(0.85) Te_(0.15) films were prepared by thermal evaporation under vacuum on glass substrate. The optical and electrical properties of as deposited and irradiated Se_(0.85) Te_(0.15) films with different γ-doses are reported.

The optical constants (absorption coefficient (α), extinction coefficient (k), refractive index (n) and dielectric constants (?, ?) of unirradiated and irradiated films were calculated. The value of allowed direct optical energy gap of Se_(0.85) Te_(0.15) films increased from 1.47 eV. to 1.72 eV. with increasing the γ-doses to 2.5 Mrad. The irradiated films have lower resistivity than those as deposited films (unirradiated). The activation energy (ΔE) increases from 0.72 eV. to 0.86 eV. with increasing γ-doses to 2.5 Mrad.     

Preparation and characterization of ZnO thin films prepared by thermal oxidation of evaporated Zn thin films

In this paper, the experimental results regarding some structural, electrical and optical properties of ZnO thin films prepared by thermal oxidation of metallic Zn thin films are presented.Zn thin films (d=200–400 nm) were deposited by thermal evaporation under vacuum, onto unheated glass substrates, using the quasi-closed volume technique. In order to obtain ZnO films, zinc-coated glass substrates were isochronally heated in air in the 300–660 K temperature range, for thermal oxidation.X-ray diffraction (XRD) studies revealed that the ZnO films obtained present a randomly oriented hexagonal nanocrystalline structure. Depending on the heating temperature of the Zn films, the optical transmittance of the ZnO films in the visible wavelength range varied from 85% to 95%. The optical band gap of the ZnO films was found to be about 3.2 eV. By in situ studying of the temperature dependence of the electrical conductivity during the oxidation process, the value of about 2×10⁻² Ω⁻¹ m⁻¹ was found for the conductivity of completely oxidized ZnO films.     

The effect of rf power on the growth of InN films by modified activated reactive evaporation

We report the effect of rf power on the structural, optical and electrical properties of InN films grown by modified activated reactive evaporation. In this technique, the substrates were kept on the cathode instead of ground electrode. The films grown at higher rf power shows preferential c-axis orientations for both silicon and glass substrates. The films prepared at 100 W show best structural, electrical and optical properties. The c-axis lattice constant was found to decrease with increase in rf power which can be attributed to reduction in excess nitrogen in the films. The band gap decreases with increase in rf power due to Moss-Burstein shift. The decrease in carrier concentration and optical band gap with increase in rf power can also be related to excess nitrogen in the film. The Raman spectra shows a red shift in the A₁(LO) and E₂ (high) mode from the reported value. The possible origin of the present large band gap is due to Moss-Burstein shift. The new film growth method opens opportunities for integrating novel substrate materials with group III nitride technologies.     

Surface plasmon resonance characterization of thermally evaporated thin gold films

The heterogeneous character of thin gold films prepared by thermal evaporation and the dependence of this heterogeneity on the rate of their deposition must be considered when exploiting their optical properties for biosensor purposes. For instance, the performance of thin gold films for surface plasmon resonance (SPR) biosensors may drastically be degraded if care is not taken to prepare a film with a high fraction of gold (>95%). We use three different models to interpret the SPR response of gold films prepared by thermal evaporation. We show that the interpretation of the SPR curves requires considering both a global heterogeneity of the gold films and a surface roughness. Our conclusions are further corroborated by scanning surface plasmon microscope (SSPM) images of these thin gold films.     

粉末靶制备的AZO/Ag/AZO透明导电薄膜的光电性能

室温下,采用射频磁控溅射AZO粉末靶和Ag靶在玻璃基底上制备Ag层厚度分别为12 nm和15 nm两组对称结构掺铝氧化锌/银/掺铝氧化锌(AZO/Ag/AZO)透明导电薄膜,研究了Ag层和AZO层厚度对薄膜光电性能的影响。结果表明:3层薄膜的可见光区平均透光率达到了80%,550 nm处的最高透过率达到了88%,方块电阻小于5 Ω/□。Ag层厚度是影响AZO/Ag/AZO薄膜光电性能的主要因素,AZO层的厚度对薄膜光学性能影响较大。     

Preparation and characterization of indium tin oxide films formed by oxygen ion beam assisted deposition

Indium tin oxide (ITO) films were produced by low-energy oxygen ion beam assisted electron-beam evaporation. The dependence of surface morphology, electrical and optical properties on evaporation rate, oxygen ion beam energy and density, as well as substrate temperatures was characterized by atomic force microscopy, X-ray photoelectron spectroscopy, Hall-effect and optical transmittance measurements. The results show that high-quality ITO films (resistivity of 7.0×10⁻⁴ Ω cm, optical transmittance above 85% at wavelength 550 nm, surface roughness of 0.6 nm in root mean square) can be obtained at room temperature.     

Optimization of the optical and electrical properties of electron beam evaporated aluminum-doped zinc oxide films for opto-electronic applications

Aluminum-doped zinc oxide (AZO) thin films have been deposited by electron beam evaporation technique on glass substrates. The structural, electrical and optical properties of AZO films have been investigated as a function of annealing temperature. It was observed that the optical properties such as transmittance, reflectance, optical band gap and refractive index of AZO films were strongly affected by annealing temperature. The transmittance values of 84% in the visible region and 97% in the NIR region were obtained for AZO film annealed at 475 °C. The room temperature electrical resistivity of 4.6×10⁻³ Ω cm has been obtained at the same temperature of annealing. It was found that the calculated refractive index has been affected by the packing density of the thin films, whereas, the high annealing temperature gave rise to improve the homogeneity of the films. The single-oscillator model was used to analyze the optical parameters such as the oscillator and dispersion energies.     

Zn1-x-yNaxCoyO薄膜的脉冲激光沉积制备及表征

采用脉冲激光沉积技术,在Si(111)衬底上成功制备出不同含量Na,Co共掺的ZnO薄膜.利用X射线衍射仪、原子力显微镜、荧光光谱仪以及四探针电阻率测试台对薄膜的结构、表面形貌和光电性质进行了表征.重点讨论了不同掺杂浓度对薄膜光电性质的影响.结果表明:Na,Co共掺没有改变ZnO的六角纤锌矿结构且掺杂导致薄膜仅有的的紫外发光峰出现红移.当Na,Co掺杂浓度分别为10%时,峰值最强且红移最明显,发光峰波长为397 nm,薄膜的电阻率最低,达到了8.34×10^-1 Ω ·cm.深入讨论了 关键词： 脉冲激光沉积 1-x-yNa_xCo_yO薄膜')" href="#">Zn_1-x-yNa_xCo_yO薄膜 光电性质 红移     

Electron beam evaporated LaF3 thin films prepared by different temperatures and deposition rates

LaF₃ thin films were prepared by electron beam evaporation with different temperatures and deposition rates. Microstructure properties including crystalline structure and surface roughness were investigated by X-ray diffraction (XRD) and optical profilograph. X-ray photoelectron spectroscopy (XPS) was employed to study the chemical composition of the films. Optical properties (transmittance and refractive index) and laser induce damage threshold (LIDT) at 355 nm of the films were also characterized. The effects of deposition rate and substrate temperature on microstructure, optical properties and LIDT of LaF₃ thin films were discussed, respectively.     

Effect of composition and forming parameter on evaporated CdSeTe films deposited at room temperature

Amorphous films of the ternary compound CdSeTe, of composition in the range 0-10 at.% Cd and with a thickness of about 200 nm, have been prepared by thermal evaporation. The optical band gap was determined and found to be in the range 0.5-1.0 eV and arose from indirect transitions. A sharp decrease in the value of optical band gap (E_opt) is observed. The electrical properties of Cd thin films have been studied extensively. In general dc measurements have indicated Ohmic conductivity at low electric fields resulting from the thermal excitation of carriers from centers in the band gap. When the temperature is low enough so that carriers cannot be excited into one of the allowed bands, the dominant conduction may take place via hopping, whereby carriers hop from occupied to unoccupied sites located within a band of localized states situated within the band gap. The electrical and optical data were consistent and realized from the binding energy represented by the cohesive energy values. The generalized (8−n) rule was used to estimate the average co-ordination number. The obtained results were treated in the frame of the chemical bond approach proposed by Bicerano and Ovshinsky. The phase separation phenomena and the morphology were also studied for the prepared films.     

Intentionally incorporated defect and its consequences in oxide thin film through Radio Frequency Magnetron Sputtering Technique

Radio Frequency Magnetron Sputtering Technique has been employed to prepare metal oxide thin film of ZnO and CdO. The films were deposited in such condition that some point defects like oxygen vacancies have been intentionally incorporated. The defects appeared with significant modification in the properties of the thin films. The prepared films were characterized by studying with X-ray diffraction study, X-ray photoelectron spectroscopic measurement, optical transmittance measurement, and electrical study. The electrical properties are found to change profoundly with the defect concentration. Consequently the optical properties also have been changed.     

Hydrogen gas-sensing properties of Pt/WO<Subscript>3</Subscript> thin film in various measurement conditions

A well-known gasochromic material is Pt particle-dispersed tungsten trioxide (Pt/WO₃). Its optical properties could make it effective as a hydrogen gas sensor. In this study, Pt nanoparticle-dispersed WO₃ thin films were prepared using the sol–gel process, and their optical and electrical properties dependent on the working environment (i.e., temperature, hydrogen gas concentration, oxygen partial pressure, etc.) were investigated. The Pt/WO₃ thin films prepared at 400 °C showed the largest change in optical transmittance and electrical conductivity when exposed to hydrogen gas compared with the films prepared at other temperatures. The optical absorbance and electrical conductivity were found to be dependent on the hydrogen and oxygen gas concentration in the atmosphere because generation and disappearance of W⁵⁺ in the thin films depend on the equilibrium reaction between injection and rejection of H⁺ into and from the thin films. In addition, the equilibrium reaction depends on the hydrogen and oxygen gas concentrations.