ATO Film Research Articles

Regulation of structural, electrical and optical properties of Sb-doped SnO2 films prepared with different O2 flow rates by rapid thermal annealing

Effects of rapid thermal annealing (RTA) on the structure and photoelectric properties of Sb-doped SnO2 (ATO) films have not been systematically reported. In this study, ATO films were prepared by RF magnetron sputtering under different O2 flow rates (0, 15, 30 and 45 sccm), and then were subjected to RTA at different temperatures (400, 600 and 800 °C) in atmospheric environment. The results show that preferred orientations of ATO films changes from (101) to (110) crystal-plane and crystallite size increases with increasing O2 flow rate. RTA cannot change the films’ preferred orientation and crystallite size except for the film deposited in Ar atmosphere (0 sccm O2), but it can decrease the compressive stress in the films. The as-deposited and annealed films with low transmittance in visible light range (TVis) have obvious Raman scattering peak, and scattering peak of Eg vibration mode is stronger in the appearing Raman scattering peaks. Increasing O2 flow rate degrades electrically conductive properties of the films, increases TVis and makes optical band-gap (Eopt) first increase and then decrease. With increasing RTA temperature, the electrically conductive properties enhance and Eopt increases for the films deposited with all O2 flow rates, but TVis basically decreases for the films deposited with O2 flow rate of 15–45 sccm. Currently, the ATO film deposited at 15 sccm O2 and annealed at 600 °C has the best transparent conductive properties (the resistivity, sheet resistance, TVis and figure of merit are 2.09 × 10−3 Ω cm, 67 Ω/sq., 77.12%, and 1.11 × 10−3 Ω−1, respectively). In addition, element chemical states and point defects in the films were analyzed by XPS. Meanwhile, influence mechanisms of O2 flow rate and RTA on structure and properties of the films were discussed.

Chemical evolution of target surfaces during RF magnetron sputtering and its effect on the performance of TCO films

Two antimony (Sb)-doped tin oxide (ATO) targets of different densities were used to illustrate the chemical evolution of target surfaces during RF magnetron sputtering. The phase compositions, the microstructures, the chemical states, and the electrical and optical properties of the deposited ATO films were revealed. The ATO film deposited by the high-density (98%) target yielded an enhanced electrical conductivity of 3.21 × 10−2 Ω·cm (under a low power density of 100 W without substrate heating) and excellent optical properties with an average transmittance of 94.65%. For the target with pores and dielectric inclusions, the decrease in Sb content and the variation in the chemical state of tin (Sn) degraded the electrical conductivity and the optical properties of the deposited ATO films. The chemical state of the low-density ATO target varied significantly due to micro-arcing caused by warps in the electrical field during sputtering.

Facile deposition and characterization of large area highly conducting and transparent Sb-doped SnO2 thin film

We have deposited a large area (10 × 10 cm2) Sb-doped SnO2 (ATO) thin film transparent conducting electrode (TCE) using chemical spray pyrolysis method. The XRD analysis confirms tetragonal crystal structure of ATO thin film with significant preferred orientation. The XPS analysis clearly indicates the presence of Sb in +5 charge state when substituted into the SnO2 lattice. The UV–Vis transmittance spectra of the film showed average transmittance of 77.5% at 550 nm and the calculated direct band gap value was 3.82 eV. As-deposited ATO film exhibited lowest sheet resistivity and resistance of 6.715 × 10−4 Ω cm and 31.91 Ω/□ respectively due to Sb-dopant effect into the Sn lattice. Doping with Sb into SnO2 exhibits high carrier concentration of 7.899 × 1020 cm−3 and mobility of 28.45 cm2/Vs resulting in enhanced electrical transport properties. The variation of the sheet resistance of the large area deposited film is estimated across every 1 × 1 cm2 surface area. Variation of sheet resistance of the ATO film as a function of annealing temperature and duration was found to be appreciably stable. Kelvin probe study yielded a surface work function of 5.14 eV for the ATO film indicating the suitability to serve as an indium-free alternate TCE for optoelectronic device applications.

Preparation and Characterization of ATO/PS Bilayer Films with Superior Hydrophilicity

The hydrophilic films are widely used in industrial and domestic fields. Here, we report a Tin oxide film doped with antimony and Potassium silicate (ATO/PS) hydrophilic bilayer films deposited on aluminum substrates. The ATO film was prepared first on the substrates by spray pyrolysis and then PS film was deposited on ATO film by a simple dip-coating method. The structure, morphologies, wettability, stability of hydrophobicity and thermal conductivity of four kinds of samples have been analyzed in detail, including Al substrates (Al), Al substrate with ATO film (ATO), Al substrate with PS film (PS) and Al substrate with ATO/PS bilayer films (ATO/PS). The results show that the hydrophobicity of ATO/PS bilayer films is superior with contact angle of 12.5°. And the angle of ATO/PS sample is approach to 20° after being immersed in water for 48h, while 44.5° is obtained for the PS sample. The thermal conductivity value of ATO/PS sample is almost the same as the Al substrate, and also better than PS film. These results indicate that ATO/PS bilayer films have potential application in heat exchanger and other heat dispersing fields.

Transparent and flexible Sb-doped SnO2 films with a nanoscale AgTi alloyed interlayer for heat generation and shielding applications.

Transparent and flexible Sb-doped SnO2 (ATO) films with a nanoscale AgTi alloyed interlayer were fabricated for use as plasma damage-free, indium-free, thermally stable electrodes for high performance heat generating films and shielding films in smart windows. The AgTi alloy-inserted ATO film on a PET substrate showed a low sheet resistance of 6.91 ohm per square and a high optical transmittance of 90.24% without thermal annealing or intentional substrate heating. Even after deformation using an outer bending radius of 4 mm, the ATO film with a AgTi interlayer showed a constant sheet resistance due to the mechanical robustness of the AgTi interlayer. Furthermore, the AgTi-inserted ATO film showed a constant resistance even after annealing at 500 °C, unlike the Ag-inserted ATO films. Furthermore, we demonstrated the feasibility of the AgTi-inserted ATO films as transparent heat generating films and shielding films for smart windows. The effective heat generation and shield performance of the ATO/Ag–Ti/ATO multilayer suggests that the multi-functional ATO/Ag–Ti/ATO films can be used to create energy-efficient smart windows for building energy management systems and automobiles.

ITO/ATO bilayer transparent electrodes with enhanced light scattering, thermal stability and electrical conductance

Transparent electrodes based on In2O3:Sn (ITO) and SnO2:Sb (ATO) thin films have been deposited by sputtering at room temperature on soda lime glass (SLG) substrates. The preparation conditions were adjusted to obtain 250 nm-thick ITO layers with high conductivity and textured ATO coatings with various thicknesses from 80 to 200nm. These ITO and ATO films have been combined to enhance the optical scattering and the electrical conductivity of the bilayer electrodes. Besides, a suitable ATO coating can prevent the oxidation of the ITO underlayer, thus increasing the stability of the overall electrical performance. With this purpose the structure, morphology, optical and electrical properties have been analysed comparatively for SLG/ITO, SLG/ATO and SLG/ITO/ATO samples after heating in air at 500°C, studying the influence of the ATO layer thickness on the light scattering and thermal stability of the electrodes. In this way, a minimum sheet resistance of 8Ω/sq has been achieved with a 120nm-thick ATO film deposited on the 250nm-thick ITO layer; such stacked electrode has visible transmittance near 80% and average haze HT=10%, showing superior stability, light scattering and electrical performance than the isolated ITO and ATO films.

High-k titanium–aluminum oxide dielectric films prepared by inorganic–organic hybrid solution

In this paper, high-k titanium–aluminum oxide (ATO) dielectric film has been realized by using organic–inorganic hybrid precursor solution. X-ray diffraction pattern revealed that the ATO films (Ti content less than 67 at%) remain amorphous phase for annealing treatment at 400 °C. And all of the amorphous ATO films had very smooth and uniform surface with root mean square (RMS) roughness of less than 0.5 nm. Meanwhile, the results showed that the ATO film (Ti:Al = 1:8) had the best performance, including RMS roughness of 0.33 nm, relative permittivity of 15, and leakage current density of 1.41 × 10−6 A/cm2 at 1 MV/cm.

Electrochemical & microstructural investigations of magnetron sputtered nanostructured ATO thin films for application in Li-ion battery

Nanostructured Sb-doped SnO2 (ATO) thin films were prepared by radio frequency magnetron sputtering, and their electrochemical properties were evaluated versus Li metal in Li/electrolyte/ATO cells. The ATO film electrodes show high specific capacity, stable cycling performance and good rate performance. Discharge capacities were 1482, 973, 636, and 447mAhg−1 for the first, second, 100th and 200th cycles, respectively. Electrochemical reaction products of ATO films in the cell were examined by analyzing the phase evolution of the ATO electrodes electrochemically induced at various stages using high resolution transmission electron microscopy. The results reveal the electrochemical reaction as follows: the decomposition of SnO2 and formation of metallic Sn and Li-Sn alloy during discharge process; reversible de-alloying of Li-Sn, reaction between Sn and Li2O, and even partial formation of SnO2 during charge process. Nano-structured characteristics were maintained during the charge-discharge processes, to which good electrochemical performance of the ATO thin films is mainly attributed.

Properties of Sb-doped SnO2 transparent conductive thin films deposited by radio-frequency magnetron sputtering

Transparent conducting Sb-doped SnO2 (ATO) thin films were prepared on quartz substrates by radio-frequency magnetron sputtering technique. The X-ray diffraction measurement shows that the as-deposited ATO film is of tetragonal crystal structure. Electrical and optical properties were investigated by Hall and optical measurements. The resistivity and optical transmittance of the ATO thin films are of the order of 10−3 Ω·cm and over 85%, respectively. The lowest electrical resistivity of the films was found to be about 1.99×10−3 Ω·cm. Finally, the organic solar cell with the ATO thin film as an anode was prepared, and a power conversion efficiency of 1.11% was achieved.

Fiber-like stripe ATO (SnO2:Sb) nanostructured thin films grown by sol–gel method: Optical, topographical and electrical properties

Abstract Sb-doped SnO 2 thin films were deposited on glass substrates by sol–gel dip coating technique. The effects of dopant concentration on structural, morphological, electrical, and optical properties of ATO thin films were investigated. The compositional analysis of the films carried out by using EDX and XPS. The analyses confirmed the presence of Sb in SnO 2 thin films. The XRD results showed a tetragonal rutile structure of SnO 2 and the crystallite size of the films decreased with increasing dopant concentration. The surface morphology of the films is found to depend on the doping concentration. The wrinkle network with uniformly protruding fiber like stripes arranged randomly on the film surface can be observed at a higher Sb content (above 7 mol%). The surface topographical image exhibited that the surface roughness of films increased by Sb doping. A minimum resistivity of 1.72 × 10 −2 Ω cm was obtained for the ATO (10 mol% Sb) film. The Hall mobility of the ATO films decreased with increasing the Sb concentration. The optical study revealed that transmittance of the films was diminished by doping and also a gradual increase in the optical band gap was observed by enhancement of dopant concentration. The compositional dependence of optical parameters such as refractive index, extinction coefficient, dispersion energy, real and imaginary parts of the dielectric constant and optical conductivity were also investigated. The PL measurements illustrated the photoluminescence quenching with increasing Sb content up to 10 mol%.

Preparation and properties of ATO films and their effects on the TiO2/ATO system

Multilayered TiO2/ATO thin films were prepared by the spin-coating method to evaluate the electronic interactions and the effect of the experimental conditions on optical transparency, electric resistivity and carrier density. ATO chemical composition, number of layers and annealing temperature were modified to study their effect on the global properties of the TiO2/ATO system. TiO2/ATO films exhibited an optical transparency as high as 81 % in the visible wavelength and a strong absorption within the UV spectra. Electric resistivity as low as 3.4 × 10−1 Ω·cm was measured for TiO2/ATO films. Optical properties were influenced mainly by the presence of upper TiO2 layer and ATO film thickness. The effect of ATO film thickness, composition and annealing temperature on TiO2/ATO transparency and resistivity are discussed.

Structural, Electrical, and Optical Properties of SnO2:Sb Films Prepared on Flexible Substrate at Room Temperature

In this study, antimony (6 wt %)-doped tin oxide (ATO) films were prepared on a poly(ether sulphone) (PES) flexible substrate by radio frequency (RF) magnetron sputtering at room temperature, with varying deposition parameters such as RF power and working pressure. The RF power was varied from 50 to 150 W in steps of 25 W. The working pressure was varied from 0.67 to 1.2 Pa in steps of 0.27 Pa at room temperature. The thickness of the deposited ATO films was about 200 nm. The (110), (101), (200), and (211) diffraction peaks were observed for the ATO films deposited with two different conditions. All the samples were found to be crystalline with a cassiterite tetragonal (rutile type) structure that has a preferred orientation in the (101) direction, which is structurally stable and exists mainly in nature. The ATO film deposited at a RF power of 125 W with a working pressure of 0.67 Pa showed the lowest resistivity of 6.9 ×10-3 Ω cm, and the optical transmittance was 80.1% in the visible wavelength range from 400 to 800 nm.

Properties of Transparent Conducting ATO Films Deposited by RF Magnetron Sputtering

We have discussed the effects of substrate temperature and Sb2O3 composition on properties of ATO thin films by RF magnetron sputtering. Above 250°C of substrate temperature, the films exhibited good crystallographic and electrical properties. At fixed substrate temperature of 250°C, the electrical properties of ATO film were enhanced with increasing Sb concentration. From the AES depth profile and XRD pattern for the film with 92:8 of SnO2:Sb2O3 composition, we found that Sb was uniform and there was no secondary phase or phase separation in ATO film. The rms roughness of the films was minimum value, 1.54 nm, at the composition of 92:8 wt%. For the ATO thin film with 92:8 composition exhibited good chemical endurance and thermal stability, which seems to be good for touch panel applications.

THE EFFECT OF ANNEALING ATMOSPHERES ON STRUCTURAL, ELECTRICAL AND OPTICAL PROPERTIES OF THE ATO FILMS PREPARED BY RF MAGNETRON SPUTTERING

Antimony-doped tin oxide ( SnO 2: Sb , ATO) films were deposited on 7059 corning glass substrate by radio frequency magnetron sputtering method using a commercial ceramic target with a mixture of SnO 2 and Sb (6 wt.%) for application to transparent electrodes. The ATO film was deposited at working pressure of 5 mTorr and RF power of 175 W without substrate heating. The thickness of the deposited ATO films was about 150 nm using a surface profiler (alpha-step). The films were annealed at temperatures ranging from 300 to 600°C in step of 100°C using RTA equipment in vacuum and oxygen atmosphere, respectively. We investigated the effects of the post-annealing atmospheres on structural, electrical and optical properties of the ATO films. The results show that the increase of the annealing temperature improved the crystallinity of the ATO films, increased the grain size and improved electrical and optical properties, regardless of annealing atmospheres. The resistivity of the ATO films decreased significantly with higher annealing temperatures in vacuum and oxygen atmosphere. In the visible range from 400 to 800 nm, the optical transmittance of the ATO films increased over 90% at higher annealing temperature.

Synthesis and characterization of SnO2 :Sb film by dc magnetron sputtering method for applications to transparent electrodes

Transparent conducting Sb-doped SnO2 (antimony-doped tin oxide: ATO) films were prepared on Corning glass substrate by dc magnetron sputtering using SnO2 mixed with 6 wt.% of Sb at various substrate temperatures of 100–600 °C and dc powers of 100–200 W. All ATO films were deposited with a thickness of 300 nm. X-ray defractometer (XRD) measurements showed the ATO films to be crystallized with strong (101) orientation as substrate temperature increases over 300 °C. Grain size was calculated from the XRD spectra using the Scherrer equation. The ATO film in this work had a resistivity of order 10− 3 and carrier concentration of order 1020.