Structural, morphological and optical properties of thermal annealed TiO thin films

Structural, morphological and optical properties of TiO thin films grown by single source thermal evaporation method were studied. The films were annealed from 300 to 520 °C in air after evaporation. Qualitative film analysis was performed with X-ray diffraction, atomic force microscopy and optical transmittance and reflectance spectra. A correlation was established between the optical properties, surface roughness and growth morphology of the evaporated TiO thin films. The X-ray diffraction spectra indicated the presence of the TiO₂ phase for the annealing temperature above 400 °C.     

Correlation between optical, electrical and structural properties of vanadium dioxide thin films

VO₂ films have been prepared on normal microscope glass slides by reactive rf magnetron sputtering of vanadium target in a mixture of argon and oxygen. Optical properties of the films were investigated by the UV/Vis/NIR Perkin–Elmer Lamda 9. Transmission electron microscope and atomic force microscope were used to investigate the structure of the films. Correlation between structural and optical properties of VO₂ thin films is investigated with respect to the dependence of both to substrate temperature.     

Correlation study between structural, magnetic and transport properties of annealed Co thin films

This paper presents structural, magnetization and transport properties measurements carried out on as-deposited Co (400 Å) thin film as well as samples annealed in the temperature range 100-500 °C in steps of 100 °C for 1 h. The samples used in this work were deposited on float glass substrates using ion beam sputtering technique. The magnetization measurements carried out using MOKE technique, clearly indicates that as-deposited as well as annealed samples up to 500 °C show well saturation magnetization with applied magnetic field. The as-deposited sample shows coercivity value (H_c) of 26 Oe, and it is increased to 94 Oe for 500 °C-annealed sample. A minimum coercivity value of 15 Oe is obtained for 200 °C annealed sample. The XRD measurements of as deposited films show microcrystalline nature of Co film, which becomes crystalline with increase in annealing temperature. The corresponding resistivity measurements show gradual decrease in resistivity. AFM technique was employed to study the surface morphology of as deposited film as well as annealed thin films. Observed magnetization, and resistivity behaviour is mainly attributed to the (i) change in crystal structure (ii) increase in grain size and (iii) stress relaxation due to the annealing treatment.     

Correlation between structural and electrical properties of ZnO thin films

Thin ZnO films were deposited by radio frequency (r.f.) and direct current (d.c.) magnetron sputtering techniques onto glass substrates. Microstructural and electrical properties of ZnO films were studied using X-ray diffractometer (XRD), scanning electron microscope (SEM) and resistivity measurements. It was found that the size of the crystallites in the d.c. deposited films increased with increasing film thickness, while the crystallite size of r.f. deposited films remained unchanged. The d.c. deposited grains also had much stronger orientation related to the substrate than the r.f. films. XRD data indicated that the thin films with d<350 nm for r.f. and <750 nm for d.c. films have a very high degree of ZnO nonstoichiometry. This agreed well with the conductivity measurements and R(T) behaviour of the films with different resistance R. It was also found that the electrical resistivity of the samples increased exponentially with the thickness of films.     

Structural,optical and electrical properties of CdZnS thin films

The thin films of Cd_1-x Zn _x S (x?=?0, 0.2, 0.4, 0.6, 0.8 and 1) have been prepared by the vacuum evaporation method using a mechanically alloyed mixture of CdS and ZnS. The structural, optical and electrical properties have been investigated through the X-ray diffractometer, spectrophotometer and Keithley electrometer. The X-ray diffraction patterns of these films show that films are polycrystalline in nature having preferential orientation along the (002) plane. In the absorption spectra of these films, absorption edge shifts towards lower wavelength with the increase of Zn concentration. The energy band gap has been determined using these spectra. It is found that the energy band gap increases with increasing Zn concentration. The electrical conductivity of so prepared thin films has been determined using a I–V characteristic curve for these films. The result indicates that the electrical conductivity decreases with increasing Zn content and increases with temperature. An effort has also been made to obtain activation energy of these films which increases with increasing Zn concentration in CdS.     

Preparation and electrical properties of ITO thin films by dip-coating process

Indium tin oxide (ITO) thin films were prepared on quartz glass substrates by a dip-coating process. The starting solution was prepared by mixing indium chloride dissolved in acetylacetone and tin chloride dissolved in ethanol. The ITO thin films containing 0 20 mol% SnO₂ were successfully prepared by heat-treatment at above 400 °C. Chemical stability of sol were investigated by using a FTIR spectrometer. The electrical resistivity of the thin films decreased with increasing heat-treatment temperature, that is carrier concentration increased, and mobility decreased with increasing SnO₂ content. The ITO thin films containing 12 mol% SnO₂ showed the minimum resistivity of =1.2 × 10^–3 ( cm). It also showed high carrier concentration of N=1.2 × 10²⁰(cm^–3) and mobility _H=7.0(cm² V^–1 s^–1).     

Surface morphological, structural, electrical and optical properties of annealed vanadyl tetra tert-butyl 2, 3 naphthalocyanine thin films

Vanadyl Tetra Tert-Butyl 2, 3 Naphthalocyanine (VTTBNc) thin films have been grown at room temperature by physical vapor deposition technique. The article describes the role of air and vacuum annealing on VTTBNc thin film surface morphology, structure, electrical conductivity and optical absorbance on the basis of respective measurements like atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray Diffractogram (XRD), DC electrical conductivity with integrated electrodes and UV-visible absorption spectra.     

Influence of thermal annealing on electrical and optical properties of Ga-doped ZnO thin films

Influence of thermal annealing on electrical properties of GZO films has been studied by means of Hall effect measurements and optical characterization based on Drude model analysis for transmission and reflection spectra. Electrical resistivity increased with increasing annealing temperature. Changes of electrical properties were compared between air and N₂ gas atmosphere. Thermal stability in the air was worse compared to the N₂ gas atmosphere. Annealing at rather high temperature caused decrease in the Hall mobility and increase in optical mobility. The difference between the Hall mobility and the optical mobility was attributed to carrier scattering at grain boundaries. Three kinds of deposition method, ion plating using DC arc discharge, DC magnetron sputtering, and RF power superimposed DC magnetron sputtering were compared in terms of the thermal stability.     

Morphological, optical and electrical properties of samarium oxide thin films

We present here results on samarium oxide thin films, obtained by pulsed laser deposition and by radio frequency assisted pulsed laser deposition. Three different substrate types were used: silicon, platinum covered silicon and titanium covered silicon. The influence of the deposition parameters (oxygen pressure and laser fluence) on the structure and morphology of the thin films was studied. The substrate-thin film interface zone was investigated; the optical and electrical properties (the losses, dielectric constant and leakage currents) were also determined.     

Some electrical and optical properties of InSe thin films

It has been found that amorphous InSe thin films formed by vacuum evaporation on pyrex substrates held at room temperature are gradually transformed to the polycrystalline phase when subjected to thermal treatment. Transformation studies have been monitored by electrical resistance and optical transmission measurements completed by micrographs of thin film surfaces at room temperature. The electrical resistance vs. temperature dependence shows that the temperature range investigated can be divided into three regions. By heating the sample to a temperature t₁, which lies between 100° and 130 °C, depending on the sample thickness, its resistance decreases abruptly by six orders of magnitude. In the second region, between temperatures t₁ and t_h (t_h lying between 358° and 390 °C), the resistance remains low, while at t_h it rises rapidly again. Micrographs show that the recrystallization process begins at the temperature t₁ and is completed at t_h. Electrical measurements show that the samples attain semiconducting characteristics simultaneously with completed recrystallisation.     

氮化处理对ITO薄膜光电特性影响

利用射频磁控溅射在玻璃衬底上制备了氧化铟锡(ITO)薄膜,分别采用两种方法对薄膜进行氮化处理,即:(1)利用氩气溅射在室温下制备薄膜,随后在氮气和氨气气氛下对薄膜进行热处理;(2)利用氩气/氮气共溅射成膜.利用X射线衍射、霍尔效应、UV-vis-NIR分光光度计等测试手段对薄膜样品进行表征,对比研究了两种氮化处理方法对ITO薄膜光电特性的影响.结果发现对于低温生长的薄膜,两种方法均能明显提高其在可见光区的透过率.氩气/氮气共溅射的方法会降低薄膜的结晶程度,降低载流子浓度,但使得其紫外/可见/近红外光谱发生明显红移;而热处理方法则能增加薄膜的结晶程度,提高其导电能力.     

Surface morphology,structural and electrical properties of RF-sputtered ITO thin films on Si substrates

Series of indium tin oxide (ITO) thin films were deposited onto Si(100) substrate by RF sputtering. The film thickness ranges from 61 to 768 nm. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) experiments were performed to study the structure and the surface morphology of these films. The electrical properties were obtained by a Hall effect measurement system; the electrical resistivity \(\rho \), the carrier concentration n and the mobility \(\mu \) were measured. Annealing experiments were carried out in the air at \(400{^{\circ }}\hbox {C}\) for 60 min. The different physical parameters were investigated as a function of thickness before and after annealing. The effects of power and deposition rate were also addressed. We noted that the behaviour of some parameters with thickness is different before and after annealing. All these results are discussed and correlated in this article. Also, the results of the present ITO/Si system were compared to those of the ITO/glass, we have previously published.     

Characterization of optical, electrical and structural properties of silverphthalocyanine thin films

Silverphthalocyanine thin films are deposited on to glass substrates by thermal evaporation technique. Optical data have been obtained from both absorption and reflectivity spectra over the wavelength range 350–900 nm. The absorption coefficient α and extinction coefficient k are estimated from the spectrum. The mechanism of optical absorption follows the rule of direct transition. Using α and k, the refractive index and the dielectric constants are determined. Electrical conductivity studies are done at different substrate temperatures and using the Arrhenius plot the activation energy in the intrinsic region and impurity region is estimated. From the X-ray diffractograms of AgPc thin films subjected to heat treatments the variation of grain size is also studied. The scanning electron microscopy images are taken to study the surface morphology of the films. Silver phthalocyanine thin film is expected to find application in the fabrication of organic transistors and LED devices.     

Determination of optical and electrical properties of ZnSe thin films

A thin film of zinc selenide (ZnSe) was deposited onto a clean glass substrate using a vacuum evaporation technique. This thin film was characterized through X-ray diffraction, which indicated that the film was polycrystalline in nature. Absorption and transmission spectra of this thin film were recorded using a spectrophotometer. The energy band gap, refractive index and extinction coefficient were determined using these spectra. It was found that the energy band gap of ZnSe film was 2.55 eV. It was also observed that the refractive index and extinction coefficient of the film decreased with the increase of wavelength. The conductivity of this thin film was determined by current–voltage measurement using an electrometer over the temperature range from room temperature to 413 K. It was observed that conductivity increased with increase in temperature. This is explained on the basis of structural changes occurring due to the change in grain size and the increase in carrier density.     

Investigation of optical and electrical properties of ZnO thin films

Zinc oxide (ZnO) thin films were deposited on Si substrates using various working pressures by magnetron sputter. The resistivity of the deposited ZnO films decreases with working pressure, and the resistivity of 4.3 × 10⁻³ Ω cm can be obtained without post annealing. According to the optical transmittance measurements, the optical transmittance above 90% in the wavelength longer than 430 nm and about 80% in the wavelength of 380 nm can be found. Using time-resolved photoluminescence measurement, the carrier lifetime increases with working pressure due to the reduction of nonradiative recombination rate. The reduction of nonradiative recombination rate is originated from the decrease of oxygen vacancies in the ZnO films deposited at a higher working pressure. This result is verified by the photoluminescence measurements. Besides, by increasing the working pressure, the absorption coefficient was decreased and the associated optical energy gap of ZnO thin films was increased.     

Electrical and optical properties of annealed gallium arsenide thin films on glass substrates

The effects of annealing in vacuum on the electrical and optical properties of GaAs thin films deposited by the flash evaporation method were studied. Thin films of compound GaAs deposited upon glass substrates at room temperature were annealed in a vacuum of 2×10^–6 torr at different temperatures up to 350° C. The properties of the films depended strongly on annealing temperature. The lowest resistivity measured was about 1.6 × 10⁴ cm at an annealing temperature of about 240° C. The activation energy of as-deposited and annealed films were measured and compared. Optical absorption measurements of the asdeposited samples and the samples annealed at a temperature of 240° C were made as a function of photon energy.     

Growth of ITO thin films by magnetron sputtering: OES study,opticaland electrical properties

In this work tin doped indium oxide (ITO) thin films were deposited onto soda lime glass substrates by the direct current magnetron sputtering system analyzing process of deposition with optical emission spectroscopy (OES). The dependence of electro-optical characteristics of the deposited films on the sputtering pressure, O₂/Ar working gas flow ratio and the discharge power was investigated. Transparency of the ITO films was measured using the ultraviolet and visible light spectrometer (UV–vis). The X-Ray photoelectron spectroscopy (XPS) method was applied for analysis of thin films surface chemical composition. It was found that in-situ measurement of plasma emission spectra allowed prediction and control of parameters of ITO thin films, namely resistivity and transparency. The correlation between the thin films resistivity, optical transparency and kinetics of deposition was examined.     

Modification of optical and electrical properties of ITO using a thin Al capping layer

In this study, the work function, transmittance, and resistivity of indium tin oxide (ITO) thin films were successfully modified by depositing an Al capping layer on top of ITO with subsequent thermal annealing. The 5 nm thick Al layer was deposited by a conventional dc magnetron sputtering method and the layer was converted into an aluminum oxinitride by subjecting the sample to rapid thermal annealing (RTA) under a nitrogen atmosphere. The films exhibited a high transmittance of 86% on average within the visible wavelength region with an average resistivity value of 7.9 × 10^− 4 Ω cm. Heat-treating the Al/ITO films via RTA resulted in the decrease of the optical band gap from that of bare ITO. In addition, the films showed red-shift phenomena due to their decreased band gaps when the heat-treatment temperature was increased. The resultant electrical and optical characteristics can be explained by the formation of aluminum oxinitride on the surface of the ITO films. The work function of the heat-treated films increased by up to 0.26 eV from that of a bare ITO film. The increase of the work function predicts the reduction of the hole-injection barrier in organic light-emitting diode (OLED) devices and the eventual use of these films could provide much improved efficiency of devices.