Annealing Effect on Nanocrystalline SnO2 Thin Films Prepared by Spray Pyrolysis Technique

In recent years, a transparent conducting oxide (TCO) SnO2 semiconductor have gained considerable attention due to their potential application in gas sensors. More number of studies on TCO oxide have focused on the semiconducting metal oxides in which an intensive argument is that the transparent semiconductors. The SnO2 thin films were deposited at 400 °C and then annealed at 500 °C and 600 °C and its structural, optical and electrical properties were characterized. The doping stoichiometric ratio was maintained as 4% and the resulting solution was sprayed on glass substrate which was kept at nozzle distance of 25 cm and the spray rate was 10 mL/min. The prepared pure SnO2 thin films have been characterized by different methods such as XRD, FESEM, UV-Vis NIR and EDAX analyses. It was found that the nanocrystalline SnO2 grains possesses structural features of the tetragonal rutile structure. Hence the prepared thin films are justified to be nanocrystalline and also the mean crystalline size decreased with respect to annealing temperature.

Bi-Doped SnO2 Transparent Conducting Thin Films Deposited By Spray Pyrolysis: Structural, Electrical, Optical And Photo-Thermoelectric Properties

In this research, light and heavy Bi-doped SnO2 thin films were prepared on glass substrates by spray pyrolysis technique. The effect of heavy doped-Bi on the structural, morphological, electrical, photo-thermo-electrical, optical properties of SnO2 films has been investigated. The Bi/Sn atomic ratios (x = [Bi/Sn]) were varied from 0 to 0.30 in the spray solution. X-ray diffraction analysis showed the formation of SnO2 tetragonal rutile structure in low doped deposited films and amorphous structure for heavy Bi-doped SnO2. Also, the SnO2-Bi2O3 binary thin films were formed for x= [Bi/Sn] =0.05. Scanning electron microscopy (SEM) images indicated that nanostructure of the condensed films has a rectangular-particle growth toward particle- spherical growth. The Hall effect measurements have shown n-type conductivity in all deposited films. The lowest sheet resistance of 39.3 MΩ/□ and highest carrier concentration of n=4.53 × 1018 cm−3 were obtained for the thin film deposited with x = 0.10. The maximum of the Seebeck coefficient (S)=325 μVK−1 and figure of merit (ZT) = 1.85 was obtained for the thin film deposited with x = 0.20. The average transmittance of films varied over the range of T=72%-84%. The band gap values of samples were obtained in the range of Eg=3.52–3.88 eV for direct band gap. From the photoconductivity studies, the sample prepared with x = 0.20 exhibited the highest photoconductivity among the SnO2: Bi thin films.

Thin Films Growth of SnO_2:F/CdS/CdTe, and Studies of Their Physical and Optical Properties using Spray Pyrolysis Techniques

Fluorine doped tin oxide, Cadmium Sulphide and Cadmium Telluride thin films have been deposted on Soda Lime glass substrate at respectively by spray pyrolysis (SP) technique and are important semiconductor materials in optoelectronic devices such as optical sensors, light-emitting diodes, transistors and photovoltaic cells. thin films were characterized by various techniques such as X-ray diffraction, SEM and optical studies. X-ray diffraction measurements show that the deposited was found to be of cassiterite type with tetragonal rutile structure, observation of peaks of different planes on an X-ray diffraction graph of thin film showed that film obtained were cubic structure. The main peak value of thin film is seen at , which is the characteristic peak of the compound and the film structure was obtained at the major peak indicating the preferred orientation of films along direction. This confirms the formation of thin film, with (111) as the strongest preferred plane of orientation. The surface morphology of the thin films was analysed by scanning electron microscopy (SEM). The optical energy band gap of thin films are determine The results showed that the prepared FTO, CdS and CdTe films can be used in solar energy applications.

Mineral Layer Fillers for the Production of Functional Materials

An original method based on the use of technogenic waste from the processing of mineral-layered materials, in particular phlogopite for obtaining highly efficient functional compositions of the “mica-TiO2”, has been developed. The composition core is a nanosized mica flake coated with mesoporous titanium dioxide of an anatase or rutile structure. Energy-saving and environmentally friendly technological methods are based on the splitting of the mica followed by heterogeneous electrohydrolysis of a mixture of titanium (IV) sulfate solution and flake particles. No destruction of the mica surface, which provided the obtained uniform coatings, has been observed. Such coatings are used in photocatalysis processes and possess a self-cleaning capability. Core–shell compositions are more economically attractive compared with titanium dioxide, in particular TiO2 grade P25 (Degusse). The core of the transparent flake and the shell of the rutile titanium dioxide endows the final product with a pearlescent optical effect. This type of material is widely used in the manufacturing of paints and varnishes, printing inks, cosmetics, etc. The use of technogenic waste could significantly reduce the cost of the final product, which would ensure its widespread use in various industries.

Synthesis and Photochemical Properties of Monolithic TiO2 Nanowires Diode

In this paper, the structural and photochemical properties of a monolithic photochemical diode are discussed. The present structure is composed, from the top to the bottom, of a TiO2 nanowire layer, a TiO2 film, a Ti foil, and a porous layer made of Pt nanoparticles. The synthesis of the nanowires was simply carried out by Au-catalysed-assisted process; the effects of the annealing temperature and time were deeply investigated. Morphological and structural characterizations were performed by scanning electron microscopy and Raman spectroscopy. The analyses showed the rutile structure of the TiO2 nanowires. The photocatalytic properties were studied through the degradation of methylene blue (MB) dye under UV light irradiation. The nanowires induced an enhancement of the photo-degradation rate, compared to TiO2 in a bulk form, due to an increase in the surface area. Moreover, the presence of a nano-porous Pt layer deposited on the rear side of the samples provided a further increase in the MB degradation rate, related to the scavenging effect of Pt nanoparticles. The overall increment of the photo-activity, due to the nano-structuration of the TiO2 and to the presence of the Pt layer, resulted a factor 7, compared to the bulk reference. In addition, photovoltage measurements allowed to assess the effects of TiO2 nano-structuration and Pt nanoparticles on the electron accumulation.

A NOVEL pH SENSITIVITY OF SnO2 THIN FILM BASED EGFET PREPARED USING CHEMICAL BATH METHOD

Nanocrystalline (NC) tin dioxide (SnO2) thin film has been prepared using chemical bath method at low working temperature onto SiO2/Si substrates. The structural and morphological properties were studied through X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The as-deposited thin film appeared with tetragonal rutile structure. The crystallization of SnO2 film was achieved when the film was exposed to anneal at [Formula: see text]C. NC SnO2 thin film was successfully utilized as an extended gate field-effect transistor (EGFET) pH sensing. NC SnO2 film based pH-EGFET sensor displayed a notable pH sensing performance, where the sensitivity and the linearity values are equal to 25.7 (mV/pH) and 0.8489 within 2–12 range consecutive. The NC SnO2 thin film sensor has shown good pH sensor stability and reliability; thus it can be considered the best choice for flexible and disposable biosensors.

Influence of N2 doping on photodective properties of p-typed Zn-N co-doped SnO2/n-Si heterojunction

This work studied the effects of Zn and N co-doping on the crystal structure, electrical properties, and photoelectric effects of p-typed Zn-N co-doped SnO2/n-Si heterojunction. Zn and N co-doped SnO2 films (ZNTO) were deposited on n-type Si substrates at 300oC in different sputtering gas mixture Ar/N2 (% N = 0%, 30%, 50%, 60%, 70 % and 80%) from 5 wt% ZnO doped SnO2 target by the DC magnetron sputtering method. The crystal structure, surface morphology, chemical composition, electrical properties, and photoelectric effects of ZNTO films were investigated by measurements such as X-ray diffraction, FESEM, AFM, EDS, Hall, and I-V. The results showed that all films had a rutile structure, and the SnO2 (101) reflection was dominant on the optimal fabrication of 70% N2. Substitution of Sn4+ by Zn2+ and O2􀀀 by N3􀀀 were determined by the X-ray diffraction pattern (XRD) and X-ray energy scattering spectrum (EDS). The lowest resistivity for the ZNTO-5-70 film was r= 6.5010􀀀2 W.cmwith carrier concentration n = 1.461019 cm􀀀3 and hole mobility m = 6.52 cm2.V􀀀1.s􀀀1 respectively. I-V characteristics of the p – ZNTO – 5 – y/n – Si under the illumination condition showed the p-type electrical properties and their application as optical sensors. The ZNTO – 5 – y films' optical response current characteristic had high sensitivity and good reproducibility.

Формирование сверхтвердых покрытий в процессе обработки низкотемпературной плазмой азота в открытой атмосфере пленок титана

Results of the formation of superhard coatings in the low-temperature nitrogen plasma treatment process in the open atmosphere of titanium films on sapphire substrates are given. It is shown that during plasma treatment a coating of nitrogen-containing TiO2 with rutile structure is formed with a double increase (in comparison with rutile TiO2) of microhardness (up to 27 GPa). The application of this coating leads to hardening of the surface of sapphire plates by 22-23%. High productivity and implementation of synthesis in an open atmosphere make it possible to consider the proposed procedure is promising for the production of superhard coatings with high resistance to oxygen.

Research on Magnetic Property of Environmental Friendly Material SnO2: Mn, S

Tin dioxide (SnO2) is a commonly known material with the rutile structure of wide band gap ntype semiconductor which is widely used like ZnO common oxide materials in daily life. But comparing with ZnO, it has a wider band gap (about 3.6 eV), and a higher exciton binding energy 130 meV. Because of its excellent optical, electrical and other excellent physical and chemical characteristics, SnO2 has been widely adapted in thermoelectric film, gas sensor, photovoltaic devices, magnetic materials, and other related fields. A large number of theories and experiments illustrate that, after the proper doping, the remarkable improvements can be achieved. Based on the first principle, we investigated the photoelectric properties and magnetic properties when the Mn and S were doped in SnO2. It was shown by calculation that a Mn atom provides 1.52 μB magnetic moment and a S atom provides 0.06 μB, while O and Sn atoms rarely contribute to the system. In the system the magnetism is mainly derived from the Mn-3d electronic spin polarization.

Characterization of Aluminum-doped SnO2 thin films obtained by spray pyrolysis method

Aluminum doped tin oxide SnO2: Al thin films were deposited on glass substrates using spray pyrolysis method. The deposited films are a polycrystalline with a tetragonal rutile structure. The variation of lattice parameters a and c decreases as a function of Al concentration due to ionic radius of (Sn=0.71Å) and (Al=0.51Å).Crystallites sizes varied between 29.25 and 32.80 nm. Al the samples have a transmission raised between 92 and 95% in the visible range. The optical band gap energy was found to vary in the range of 3.68 - 3.85eV. Electrical measurements revealed the increase of the electrical conductivity with Al content and show a maximum at 2% of the doping and then decreases due to decrease of the grain size. Following this study we can conclude that the Aluminum doped tin oxide developed by this technique can be used in gas sensors and photovoltaic cells.