The effects of annealing temperature on characteristics of UBMS sputtered CNx films for protective coatings

The carbon nitride (CNx) films have been prepared by unbalanced magnetron sputtering (UBMS) at room temperature. The deposited CNx films have been post-annealed at temperatures ranging from 300 °C to 700 °C in increments of 200 °C using rapid thermal annealing (RTA) equipment in vacuum ambient. We investigated the effects of rapid thermal annealing on the structural, surface, and physical properties of CNx films for application of protective coatings. As the result, the increasing annealing temperature led to a decline in physical properties of CNx films such as hardness, elastic modulus, adhesion, frication coefficient, and surface roughness, however it is attributed to the improvement of the residual stress in the film. These results are related to the ordering of sp² bonded clustering and the increase of disordered graphite domain by the desorption of N contents in the films, Specially, high annealing temperature over 700 °C is attributed to the graphitization of film.     

Annealing effect on the microstructure and photoluminescence of ZnO thin films

Zinc oxide thin films have been obtained by pulsed laser ablation of a ZnO target in O₂ ambient at a pressure of 0.13 Pa using a pulsed Nd:YAG laser. ZnO thin films deposited on Si (1 1 1) substrates were treated at annealing temperatures from 400 °C up to 800 °C after deposition. The structural and optical properties of deposited thin films have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, photoluminescence spectra, resistivity and IR absorption spectra. The results show that the obtained thin films possess good single crystalline with hexagonal structure at annealing temperature 600 °C. Two emission peaks have been observed in photoluminescence spectra. As the post-annealing temperature increase, the UV emission peaks at 368 nm is improved and the intensity of blue emission at 462 nm decreases, which corresponds to the increasing of the optical quality of ZnO film and the decreasing of Zn interstitial defect, respectively. The best optical quality for ZnO thin films emerge at post-annealing temperature 600 °C in our experiment. The measurement of resistivity also proves the decrease of defects of ZnO films. The IR absorption spectra of sample show the typical Zn–O bond bending vibration absorption at wavenumber 418 cm⁻¹.     

Structural,optical and electrical characterization of ZnO:Ga thin films for organic photovoltaic applications

Gallium-doped zinc oxide (ZnO:Ga) films were prepared on glass substrates by RF magnetron sputtering. The effect of growth temperature on microstructure, optical and electrical properties of the films was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectrophotometer and four-point probe. The results show that all the films are polycrystalline and (002) oriented, and that the growth temperature significantly affects the microstructure and optoelectrical properties of the films. The film deposited at 670 K has the largest grain size of 71.9 nm, the lowest resistivity of 8.3 × 10^? 4 Ω?cm and the highest figure of merit of 2.1 × 10^? 2 Ω^? 1. Furthermore, the optical energy gaps and optical constants were determined by optical characterization methods. The dispersion behavior of the refractive index was also studied using the Sellmeir's dispersion model and the oscillator parameters of the films were obtained.     

Room temperature deposition of IZTO transparent anode films for organic light-emitting diodes

This study was to investigate anodic electrode IZTO films deposited by pulsed DC magnetron sputter at room temperature with various oxygen partial pressures onto glass substrate and to analyze the structural, electrical, and optical properties, as well as the relationship between the chemical binding state of the surface and the characteristics of IZTO films. In addition, the prepared IZTO films were used to fabricate the organic light emitting diodes (OLEDs) as an anode layer to study the device performances. The IZTO film deposited at optimal oxygen partial pressure of 2.0% in sputtering process showed the best properties, such as a low electrical resistivity and high optical transmittance of <5.1 × 10^?4 Ω cm and >80% in the visible wavelength of 400–800 nm, respectively. The OLED characteristics with the optimum condition showed good brightness and the lowest turn-on voltage of >10,000 cd/m² and 4.67 V. These results indicate that IZTO films can be a promising candidate as an alternative TCO electrode material for flexible and OLED devices.     

Preparation and optical characterization of e-beam deposited cerium oxide films

Cerium oxide films, of 0.3–1 μm thickness, were reactively deposited in the oxygen atmosphere onto quartz plates by the PVD method. An electron gun was used as an evaporation source. Films were characterized with the AFM method, Raman spectroscopy and spectrophotometrically. Optical properties of these films were examined for the wavelength range 0.2–2.5 μm. Films were characterized by high transparency, between 0.38 and 2.5 μm. The complex refractive index, n^*=n − jk, was evaluated. The dispersion characteristics for n(λ) and k(λ) were presented. We found that the refractive index strongly depends on the temperature of substrates (300 K ⩽ T_s ⩽ 673 K) during film deposition. Estimated values of the refractive index (at λ = 0.55 μm) were in the range 1.91–2.34.     

Preparation of nanocrystalline PbS thin films and effect of Sn doping and annealing on their structural and optical properties

Nanocrystalline PbS and Sn doped PbS thin films were successfully deposited on suitably cleaned glass substrate at constant room temperature, using the chemical bath deposition technique. Before, adding Sn doping content, the pure PbS thin films were deposited at room temperature for several dipping times to optimize the deposition time. After deposition, the films were also annealed at 400 °C for 1 h in air. The crystal structures of the films were determined by X-ray diffraction studies. The films were adherent to the substrate and well crystallized according to cubic structure with the preferential orientation (2 0 0). The crystallite size of the pure PbS thin films at optimized deposition time 30 min was found to be 40.4 nm, which increased with Sn content in pure PbS thin film. The surface roughness was measured by AFM studies. The band gaps of the films were determined by transmission spectra. Experiments showed that the growth parameters, doping and annealing, influenced the crystal structure, and optical properties of the films.     

Oxygen partial pressure dependence of the structural properties of CdO thin films deposited by a modified reactive vacuum evaporation process

Thin films of cadmium oxide were thermally deposited on glass substrates at partial pressures of oxygen, pO₂ in the range 1.33×10⁻² to 0.133 Pa at a substrate temperature of 160 °C. Energy dispersive analysis of X-ray fluorescence (EDAX) revealed that the CdO films deposited at pO₂ value of 4.00×10⁻² Pa were nearly stoichiometric. X-ray diffractometry (XRD) confirmed the polycrystalline nature of the film structure. All the films showed an fcc structure of the NaCl-type, as the dominant phase. The films exhibited preferred orientation along the (1 1 1) diffraction plane. The texture coefficients calculated for the various planes at different oxygen partial pressures (pO₂) indicated that the maximum preferred orientation of the films occurred along the (1 1 1) plane at an oxygen partial pressure of 4.00×10⁻² Pa. This was interpreted in terms of oxygen chemisorption and desorption processes. The lattice parameters determined from the diffraction peaks were in the range 4.655–4.686 Å. The average lattice parameter a₀ found by extrapolation using the Nelson–Riley function was 4.696 Å. Both the lattice parameter and the crystallite size were found to increase with increased partial pressure of oxygen. On the other hand, the strain and dislocation density were found to decrease as the partial pressure of oxygen was raised. A maximum (80%) in the optical transmittance at λ=600 nm and minimum in the electrical resistivity (9.1×10⁻⁴ Ω cm) of the films occurred at an optimum partial pressure of oxygen of 4.00×10⁻² Pa. The results are discussed.     

The influence of heat treatment parameters on pyrolysed TFA-derived YBCO films deposited by inkjet printing

An anhydrous TFA-derived YBa₂Cu₃O_7?δ precursor solution was deposited on all chemical solution deposition fully buffered metallic tape by means of electromagnetic drop-on-demand inkjet printing and pyrolysed in a flowing wet O₂ atmosphere. The influence of the annealing temperature and time, the gas flow rate and water vapour partial pressure on phase formation, and the morphology and superconducting performance of the resulting film, were investigated. It was found by scanning Hall probe magnetometry that reproducible superconducting films with a critical current density of 0.18 MA/cm² can be produced after annealing for 2 h at 728 °C, without metal substrate oxidation, in a flowing 200 ppm O₂ in Ar atmosphere with 31 mbar water vapour partial pressure.     

The thermal stability of high-energy ball-milled nanostructured Cu

The thermal stability of nanostructured (NS) Cu prepared by high-energy ball milling was investigated. The as-prepared samples were isothermal annealed for 1 h in the temperature range of 200–1000 °C. Effects of annealing on NS Cu samples were studied by means of Vickers hardness test, differential scanning calorimetry (DSC) and stress relaxation test. The exceptional high microhardness of as-prepared Cu sample of 1.7 GPa was not detected to decrease after annealing at 500 °C for 1 h with corresponding small value of activation volumes V^* of 22.6b³ and high value of strain rate sensitivity m of 0.0176. A prominent decrease of microhardness was detected after higher temperature annealing with a rapidly increase of activation volume and decrease of strain rate sensitivity. The present investigation demonstrates that the thermal stability of NS Cu prepared by high-energy ball milling is determined by not only the grain size but also the microstructure of grain boundaries, and during annealing process, the strain release process occurred prior to the grain growth process, therefore, the NS Cu has a relatively high thermal stability.     

Utilization of residual CdCl2 in CBD-CdS to realize grain growth in CdTe: A novel route

CdTe films were deposited by thermal evaporation onto chemical bath deposited CdS (CBD-CdS) films. The composite films were subjected to rapid thermal annealing (RTA) to observe simultaneous grain growth in both the CdS and CdTe layers. The films were characterized by measuring the compositional, microstructural and photoluminescence (PL) properties. PL spectra is dominated by the characteristic peaks (∼1.42 eV and ∼1.26 eV) associated with the virgin CdTe film. Additional features located at ∼2.56 eV and ∼1.99 eV could also be detected. The Fourier Transform Infra Red (FTIR) peak at ∼482 cm⁻¹ appeared due to the simultaneous presence of absorption peaks for CdTe stretching mode as well as Cd-S modes. Appearance of the broad peak between 1000 cm⁻¹ and 1165 cm⁻¹ may be an indication of interfacial alloying. Secondary ion mass Spectroscopy (SIMS) measurements were done to observe the compositional uniformity in the film and to measure the interfacial mixing behaviour.     

Effect of oxygen partial pressure on microstructural and optical properties of titanium oxide thin films prepared by pulsed laser deposition

Nanocrystalline titanium oxide (TiO₂) thin films were deposited on silicon (1 0 0) and quartz substrates at various oxygen partial pressures (1 × 10⁻⁵ to 3.5 × 10⁻¹ mbar) with a substrate temperature of 973 K by pulsed laser deposition. The microstructural and optical properties were characterized using Grazing incidence X-ray diffraction, atomic force microscopy, UV–visible spectroscopy and photoluminescence. The X-ray diffraction studies indicated the formation of mixed phases (anatase and rutile) at higher oxygen partial pressures (3.5 × 10⁻² to 3.5 × 10⁻¹ mbar) and strong rutile phase at lower oxygen partial pressures (1 × 10⁻⁵ to 3.5 × 10⁻³ mbar). The atomic force microscopy studies showed the dense and uniform distribution of nanocrystallites. The root mean square surface roughness of the films increased with increasing oxygen partial pressures. The UV–visible studies showed that the bandgap of the films increased from 3.20 eV to 3.60 eV with the increase of oxygen partial pressures. The refractive index was found to decrease from 2.73 to 2.06 (at 550 nm) as the oxygen partial pressure increased from 1.5 × 10⁻⁴ mbar to 3.5 × 10⁻¹ mbar. The photoluminescence peaks were fitted to Gaussian function and the bandgap was found to be in the range ∼3.28–3.40 eV for anatase and 2.98–3.13 eV for rutile phases with increasing oxygen partial pressure from 1 × 10⁻⁵ to 3.5 × 10⁻¹ mbar.     

Highly elastic and transparent multiwalled carbon nanotube/polydimethylsiloxane bilayer films as electric heating materials

Highly elastic and transparent bilayer films composed of MWCNT and polydimethylsiloxane (PDMS) layers were fabricated by spin-coating of MWCNT aqueous solution on glass plates and following curing of PDMS applied on the MWCNT layer. Morphological feature, optical transparency, tensile property, electrical property, and electric heating behavior of the bilayer films with different MWCNT layer thicknesses of 65–185 nm were investigated. SEM images confirmed that pristine MWCNTs were uniformly deposited on glass substrates and the PDMS layer was combined well with the MWCNT layer, resulting in high structural stability of the bilayer films to high elongational or twisting deformations. With the increase of the thickness of the MWCNT layer, the sheet resistance of the bilayer films decreased substantially from ~ 10⁵ Ω/sq to ~ 10³ Ω/sq, in addition to the change of the optical transmittance from ~ 75% to ~ 40% at a 550 nm wavelength. The electric heating behavior of MWCNT/PDMS bilayer films was strongly dependent on the thickness of the MWCNT layer as well as the applied voltage. Even under high twisting by 540° or continuous stepwise voltage changes for long periods of time, the MWCNT/PDMS bilayer films retained stable electrical heating performance in aspects of temperature responsiveness, steady-state maximum temperature, and electric power efficiency.     

Chemical bonding and optoelectrical properties of ruthenium doped yttrium oxide thin films

Highly infrared transparent conductive ruthenium doped yttrium oxide (RYO) films were deposited on zinc sulfide and glass substrates by reactive magnetron sputtering. The structural, optical, and electrical properties of the films as a function of growth temperature were studied. It is shown that the sputtered RYO thin films are amorphous and smooth surface is obtained. The infrared transmittance of the films increases with increasing the growth temperature. RYO films maintain greater than ∼65% transmittance over a wide wavelength range from 2.5 μm to 12 μm and the highest transmittance value reaches 73.3% at ∼10 μm. With increasing growth temperature, the resistivity changed in a wide range and lowest resistivity of about 3.36 × 10⁻³ Ω cm is obtained at room temperature. The RYO thin films with high conductivity and transparency in IR spectral range would be suitable for infrared optical and electromagnetic shielding devices.     

Enhanced dielectric and piezoelectric properties of low-temperature processed Pb(Zr,Ti)O3 thick films prepared by hybrid deposition technique with chemical solution infiltration process

High quality PZT thick films over 10 μm were successfully prepared using a chemical solution infiltration into the porous screen-printed PZT thick films. The hybrid films prepared with solution infiltration process showed very dense and uniform microstructure with large grain size at a low annealing temperature such as 700 °C. The hybrid films showed markedly enhanced electrical properties. The measured dielectric constant, the remanent polarization and the piezoelectric d₃₃ coefficient of the films were 1900, 27 μC/cm², and 230 pC/N, respectively, which were over two times higher than those of the screen printed films without the solution infiltration process.     

Structural and optical studies on dc reactive magnetron sputtered Cu2O films

Cuprous oxide (Cu₂O) thin films were deposited by dc reactive magnetron sputtering technique onto glass substrates by sputtering of pure copper target in a mixture of argon and oxygen gases under various oxygen partial pressures in the range 8 × 10^− 3–1 × 10^− 1 Pa at a constant substrate temperature of 473 K and a sputtering pressure of 4 Pa. The dependence of cathode potential on the oxygen partial pressure was explained in terms of cathode poisoning effect. The influence of oxygen partial pressure on the structural and optical properties of Cu₂O films was systematically studied. Single phase films of Cu₂O were obtained at an oxygen partial pressure of 2 × 10^− 2 Pa. The films formed at an oxygen partial pressure of 2 × 10^− 2 Pa were polycrystalline with cubic structure and exhibited an optical band gap of 2.04 eV.     

Influence of thermal annealing on optical properties and surface morphology of NiOx thin films

NiO_x thin films were deposited by reactive DC-magnetron sputtering from a nickel metal target in Ar + O₂ with the relative O₂ content of 5%. Thermal annealing effects on optical properties and surface morphology of NiO_x films were investigated by X-ray photoelectron spectroscopy, thermogravimetric analysis, scanning electron microscope and optical measurement. The results showed that the changes in optical properties and surface morphology depended on the temperature. The surface morphology of the films changed obviously as the annealing temperature increased due to the reaction NiO_x → NiO + O₂ releasing O₂. The surface morphology change was responsible for the variation of the optical properties of the films. The optical contrast between the as-deposited films and 400 °C annealed films was about 52%. In addition, the relationship of the optical energy band gap with the variation of annealing temperature was studied.     

Deposition and DC electrical characterisation of rf magnetron sputtered silicon nitride thin films

Silicon nitride (Si₃N₄) is an important insulator, frequently used in VLSI technology and for encapsulation. Conventionally it is prepared by low pressure and plasma-enhanced chemical vapour deposition, but may also be successfully deposited by RF sputtering. In the present work the sputtering process was characterised, together with some measurements on the high-field DC electrical properties in sandwich samples with Au electrodes. Films were Ar-sputtered using a Si₃N₄ sputtering target at gas pressures up to 2.12 Pa and RF discharge powers of 60–200 W. The deposition rate R was in the range 0.03–0.19 nm s^− 1 and was directly proportional to the discharge power and varied linearly with the pressure. Au electrodes formed sandwich structures with thicknesses of 50 nm–1 μm. Conductivity was essentially ohmic below 300 nm, while for the thicker films space-charge limited conductivity, dominated by an exponential distribution of traps, was observed. A mobility value of μ = 2.89 × 10^− 6 m² V^− 1 s^− 1 was derived from temperature measurements, and further analysis of the J–V data indicated a thermally generated electron concentration of 3.23 × 10¹⁹ m^− 3 and a trap concentration of 1.57 × 10²⁴ m^− 3. It was concluded that this method is suitable for the deposition of thin films, which have similar electrical properties to those prepared by chemical vapour deposition methods.     

Crystallographic parameters and electro-optical constants in ITO thin films

Indium tin oxide thin films were deposited onto soda lime glass substrates using an e-beam evaporation system. In order to improve the structural, electrical and optical properties, the films were annealed at 450 °C and 500 °C in vacuum for 1 h. X-ray diffractions of samples were analyzed by Rietveld refinement and Warren–Averbach methods. By application of Levenberg–Marquardt least square method, the experimental transmittance data were fitted completely with the transmittance data calculated via a combination of modified Drude and Forouhi–Bloomer models. Focusing on the results, it was shown that the samples had a nanosize crystallite and enhancement of the annealing temperature resulted in an increase in the conductivity, carrier concentration, lattice parameter, crystallite size and micro-strain. However, it was found that the defects were preferentially accumulated along grain boundaries in sample annealed at lower temperature. Moreover, the finding revealed that conductivity of the samples was dominated by intra-grain in indium tin oxide films. Furthermore, increasing annealing temperature resulted in the orientation in < 111> crystal texture and also brought in an additional Burstein–Moss shift.     

P-type tin–indium oxide films prepared by thermal oxidation of metallic InSn alloy films

P-type transparent conducting tin–indium oxide (TIO) films were successfully fabricated on quartz substrates by thermal oxidation of InSn alloy (In / Sn = 0.2) films that were deposited by magnetron sputtering at room temperature (R.T.). Structural and electrical properties of TIO films were investigated. X-ray diffraction studies showed that all TIO films were polycrystalline with an orthorhombic structure. The surface morphology of TIO films viewed by field emission scanning electron microscope (SEM) revealed that the films are composed of uniformly distributed submicron grains. Hall effect measurement results indicated that hole concentration as high as 9.61 × 10¹⁸ cm^− 3 was achieved. It's found that 600 °C was the optimum thermal oxidation temperature to get p-type TIO films with highest hole concentration.     

Growth and characterization of indium oxide thin films prepared by spray pyrolysis

Highly transparent and conducting indium oxide thin films are prepared on glass substrates from precursor solution of indium chloride. These films are characterized by X-ray diffraction, scanning electron microscopy and optical transmission. The preferential orientation of these films is found to be sensitive to deposition parameters. A comparative study has been made on the dependence on the thickness of the film on substrate temperatures with aqueous solution and 1:1 C₂H₅OH and H₂O as precursors. Films deposited at optimum conditions have 167 nm thickness and exhibited a resistivity of 2.94 × 10⁻⁴ Ω m along with transmittance better than 82% at 550 nm. The analytical expressions enabling the derivation of the optical constants of these films from their transmission spectrum only have successfully been applied. Finally, the refractive index dispersion is discussed in terms of the single-oscillator Wemple and Didomenico model.