Sn Doped In2S3 Films Elaborated by Spray Technique

Tin doped In2S3 films were grown by the chemical spray pyrolysis (CSP) method using the pneumatic spray set-up and compressed air as a carrier gas. The spraying solution contained indium chloride (InCl3), thiourea [CS(NH2)2] and (SnCl4) at a molar ratio of S/In = 2.5. The deposition was carried out at 350 °C on glass substrates. The Sn doping level was changed with Sn/In = 0-8 % in solution. The effect of Sn concentration on electrical, optical and structural properties of In2S3:Sn thin films have been investigated

Investigation of the Physical Properties of Sprayed Nanocrystalline In2S3 Films

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Electrical transport of sprayed In2S3:Ag thin films

Silver doped indium sulfide (In2S3:Ag) thin layers were prepared by spray pyrolysis. The Ag concentration varies in the range of 0–6 at%. The X-ray diffraction (XRD) indicates the presence of cubic phase of β-In2S3 and the crystallite size values exhibit a maximum at an Ag concentration of 4%. In addition, morphological analysis by atomic force microscopy (AFM) shows that the film surface is continuous, compact, free of cracks and depends on the Ag concentration. This observation is remarkable by evolution of surface roughness values. The films reveal a semiconductor behavior. This is observed because the electrical conductance increases with the increase of measurement temperature and the analysis of the Nyquist diagram shows the appearance of half circles, whose radius decreases by increasing the temperature from 300 K to 600 K. The electrical equivalent circuit of undoped In2S3 and In2S3:Ag4% at 460 K and 470 K contains two components connected in serial. The first is composed of a resistance R1, an inductance L and a constant phase element CPE1 in parallel and the other covers R2 and a constant phase element CPE2 that are connected in parallel. Inductive and capacitive effects exist in these materials and they depend on frequency. For Ag concentration equal or greater than 4%, the equivalent circuit is a parallel association of a resistor with a constant phase element. The activation energy is minimum for an Ag concentration of 4%.This work was supported by Spanish Ministry of Science and Innovation, Spain - Grant ID: CTQ2016-79561-R (MODENA), Fundacion Ramon Areces, Spain -Grant ID: CIVP18A3940 and Xunta de Galicia, Spain - Grant IDs: Galician Competitive Research Group ED431C-2017/22, AEMAT Strategic Partnership ED431E-2018/08. Authors would like to thank the use of RIAIDT - USC analytical facilities

Highly sensitive nitrogen dioxide gas sensors based on sprayed β-In2S3 film

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Structural and optical properties of Iodine doped zinc oxide nanoparticles

Iodine-doped zinc oxide (viz., ZnO1-xIx) nanoparticles were prepared using the sol-gel method. The samples were treated at 700 degrees C in air for 1h. The structural, morphological, and optical properties were measured using an X-ray diffractometer (XRD), a field emission scanning electron microscope (FE-SEM), UV-visible spectroscopy (UV/vis), and Raman spectroscopy, respectively. XRD results showed that the pure and doped samples have a wurtzite hexagonal structure, indicating the presence of some impurities in doped samples. The lattice parameters a and c were observed to be closer to the reported values for pure ZnO. The average crystalline size values of samples were calculated and found to be between 84 +/- 18 and 177 +/- 53 nm. The FE-SEM micrographs reveal that the particle sizes decreased from 77 to 57 nm with an increasing I concentration from x = 0.0 to x = 0.4, respectively. The morphologies of the samples were changed from particle to flask shape at higher I concentrations of 0.6 and 0.8 with average diameters of 213 and 427 nm. The increasing I concentration from 0.0 to 0.8 narrows the optical energy gap (Eg) from 3.271 to 3.242 eV due to the presence of oxygen vacancies or the lattice expansion caused by doping. Raman spectra of samples consist of the E2(high) mode, which confirmed the wurtzite hexagonal structure and it is located between 435 and 436 cm-1 except for x = 0.6, where the E2(high) mode was shifted to the higher wavenumber could be due to defects or anisotropic internal strains consistent to different growth directions

Dielectric and electrical properties of annealed ZnS thin films. The appearance of the OLPT conduction mechanism in chalcogenides

The annealing temperature (Ta) dependence of the structural, morphological, electrical and dielectric properties of ZnS thin films was investigated. In this work, we consider the as-deposited and annealed ZnS thin films at different temperatures. The as-deposited films were amorphous in nature. However, the films annealed at Ta ≥ 673 K, exhibited a hexagonal structure with (002) preferential orientation. The post annealing caused an improvement in crystallinity. The best one was observed at Ta = 723 K. Grain size increased from 7 nm to 25 nm as annealing temperature was increased from 673 K to 723 K. The surface of annealed samples is homogenous and uniform and the rms roughness is dependent on the annealing temperature: it increases with temperature within the range 5–50 nm. The film electrical conductance is found to be dependent on frequency measurement and annealing temperature: the dc conductance exhibits semi-conductor behavior for all ZnS films over the explored range of temperature and the conductance was found to enhance with increasing annealing temperature up to 623 K. In addition, it was observed that the highest conductance and lowest activation energy of ZnS films were obtained at an annealing temperature of 623 K. The mechanism of alternating current ac conductance can be reasonably explained in terms of the overlapping-large polaron tunnelling (OLPT) model for samples annealed at 623 K and 673 K. To our knowledge, this conduction mechanism was rarely found in chalcogenide materials. A significant change of Nyquist plot with annealing temperature was noted permitting the correlation between the microstructure and its electrical properties. The impedance analysis investigated that the relaxation process is well pronounced for the both annealed films at 623 K and 673 K. The dielectric behavior was associated to the polarization effect, an improvement on the dielectric constant ε′ and dielectric loss ε′′ with annealing was noticed.This work was supported by Tunisian Ministry of Higher Education and Scientific Research, Spanish Ministry of Science and Innovation – FEDER Funds (MODENA Project CTQ2016- 79461-R) and Fundaci´on Ram´on Areces (Spain, ProjectCIVP18A3940). NANOMAG group belongs to Galician Competitive Research Group ED431C-2017/22, programme co-funded by FEDER, and AEMAT Strategic Partnership (ED431E-2018/ 08, Xunta de Galicia, Spain).S

The effects of annealing process on the characteristics of β-In2S3 powder in pellet form

Due to its significant expansion as a sustainable energy source, the investigation of thin-film-based solar cells is a very important field of research among materials scientists. Nowadays, CdTe based photovoltaic devices are developed using indium sulfide (In2S3) as potential material. This study reports the effect of the annealing temperature, up to 450 °C, on In2S3 physical properties, and the consequences for the use of the In2S3 in photovoltaic devices. Structural analysis on indium sulfide pellets, made from commercial indium sulfide powder, reveals that all the samples are polycrystalline, crystallizing in the tetragonal structure (β phase). Above the annealing temperature of 400 °C, indium oxide (In2O3) is also detected. Optical absorption, in the visible and near-infrared region, is close to zero for all the samples (as-prepared and annealed). The measured band gap energy decreases with annealing temperature up to 350 °C, and increases above this temperature. The conductance of the samples increases with increasing measured temperature, confirming the semiconductor behavior. This work provides an example of the potential application of β-In2S3, in the powder form, for environmental rehabilitation.Acknowledgments The authors would like to thank the Deanship of Scientific Research at Umm Al-Qura University for supporting this work by Grant Code: (22UQU4331172DSR02)

Influence of annealing temperature on the properties of In2S3:Sn films deposited by spray pyrolysis

Tin-doped In2S3 films were grown by the chemical spray pyrolysis method using compressed air as a carrier gas. The films were annealed for 2 h at different temperatures (300, 400 and 500 °C) under nitrogen atmosphere. X-ray diffraction data show that In2S3:Sn films are polycrystalline with a cubic phase. The film grain size increases from 26 to 37 nm. The residual microstrain and dislocation network reach the values 3.08 × 10−3 and 0.73 × 1011 lines cm−2, respectively, at the annealing temperature of 500 °C. Transmittance decreases with increasing temperature. It varies in the range of 65–85 % in visible and infrared regions. The optical band gap is found to vary in the range 2.4–2.85 eV for direct transitions. The best surface state is obtained at 400 °C. The RMS roughness was estimated to be 39.4–19.8 nm. Electrical measurements at room temperature show that the sheet resistance decreases down to 130 Ω at 500 °C. The conductance and capacitance characterization at ambient temperature are also investigated and give interesting physical properties for photovoltaic applications.This work was supported by the funding of different organizations: MINECO, Spain (project MAT2012-36754- C02-01); and Xunta de Galicia, Spain (Grupos Ref. Comp. GRC2013- 044, FEDER Funds

Influence of silver doping on physical properties of sprayed In2S3 films for solar cells application

A set of silver-doped indium sulphide (In2S3:Ag) thin films were deposited by spray pyrolysis technique, at 350 degrees C, to analyze the effects of the Ag doping on the physical properties of the films. Within the limits of the analyzed dopant concentration, X-ray diffraction (XRD) revealed the polycrystalline nature of the films, crystalizing in the beta-In2S3 cubic phase, regardless the level of doping. Both XRD and Raman spectroscopy confirmed the absence of secondary phases. Optical absorption spectra evidenced that the films are opaque to ultraviolet radiation, but transparent in visible and near infrared regions of the electromagnetic spectrum. According to absorption and extinction coefficients variations, the films are smooth and homogeneous. The forbidden bandgap (E-g) increases with increasing Ag concentration. Photoluminescence measurements reveal that the films exhibit seven emissions related to In2S3 defects. The films are semiconductor and the transport phenomena are assisted via small polaron hopping. The photovoltaic effect in Ag/In2S3(n)/Si(p)/Ag is confirmed by I-V characterization in dark and under illumination.This research was partly supported by the projects HP-NANOBIO Project PID2019-111163RB-100, granted by Spanich Ministry of Science, and Project CIVP18A3940, granted by Fundación Ramón Areces, Spain. CVV thanks Xunta de Galicia (Spain) for the AEMAT (ED431E-2018/08) Strategic Partnership and the use of RIAIDT-USC analytical facilities. CVV belongs to the Galician Competitive Research Group ED431C-2017/22, co-funded by FEDER. Part of this work was also supported by the Portuguese Foundation for Science and Technology (FCT) in the frame work of the Strategic Funding UIDB/04650/2020