Tin Doping Research Articles

Comparison between results of optical and electrical measurements of free electron concentration in n-InAs specimens

A theoretical model has been developed for determining the free electron concentration in n-InAs specimens from characteristic points in far IR reflection spectra. We show that this determination requires plasmon-phonon coupling be taken into account, otherwise the measured electron concentration proves to be overestimated. A correlation between the electron concentration Nopt and the characteristic wavenumber ν+ has been calculated and proves to be well fit by a third order polynomial. The test specimens have been obtained by tin or sulfur doping of indium arsenide. The electron concentration in the specimens has been measured at room temperature using two methods: the optical method developed by the Authors (Nopt) and the conventional four-probe Hall method (the Van der Pau method, NHall). The reflecting surfaces of the specimens have been chemically polished or fine abrasive ground. The condition Nopt > NHall has been shown to hold for all the test specimens. The difference between the optical and the Hall electron concentrations is greater for specimens having polished reflecting surfaces. The experimental data have been compared with earlier data for n-GaAs. A qualitative model explaining the experimental data has been suggested.

Environmental photochemistry with Sn/F simultaneously doped TiO2 nanoparticles: UV and visible light induced degradation of thiazine dye

Environmental route such as degradation of toxic dyes can be improved through photochemical activity such as light driven photocatalytic degradation. Herein, fluorine and tin simultaneously doped TiO2 nanoparticles were synthesized and characterized. The formation of anatase phase in synthesized samples and the reduction in the crystallite size of doped TiO2 was confirmed from XRD results. The existence of O–Ti–O stretching vibration in pure and co-doped TiO2 confirmed from FTIR results. Optical studies reveal that the band gap of co-doped TiO2 is increased and hence it was concluded that the particle size of co-doped TiO2 is reduced compared with as-synthesized TiO2. The morphologies of TiO2 changed significantly with doping of fluorine and tin. It reveals majority of the particles are hexagons, pentagons and ellipse shaped and some of them are spheres with a mean particle size of 31.17 nm. PL studies showed the reduction in intensity for Sn–F/TiO2 accredited to the lesser recombination rate of electron-hole pair under UV light irradiation. Thus tin and fluorine doped TiO2 could be considered as a good candidate for photocatalytic activity. The photocatalytic activity of TiO2 and Sn–F/TiO2 nanoparticles was analyzed separately through the degradation of methylene blue (MB) under visible and UV light irradiation. The use of Sn and F ions in the synthesis of TiO2 are revealed not only create small sized nanoparticles but these water soluble nanoparticles have very good antibacterial and antifungal action by inhibiting the growth of bacteria and fungus.

Gas Sensors Based on Pseudohexagonal Phase of Gallium Oxide

The electrical conductivity of pseudohexagonal ε(κ)‐Ga2O3 films under different ambient gases (H2, NO2, O2, and CO) is studied in a range of temperatures from 400 to 550 °C. The exposure of ε(κ)‐Ga2O3 to reducing gases such as H2 and CO results in a reversible increase in current and conductance. The exposure to the oxidizing gases such as NO2 and O2 has the opposite effect. The maximum response to reducing gases (H2 and CO) is observed at 500 °C and to oxidizing gases at 550 and 450 °C for NO2 and O2, respectively. The highest sensitivity to H2 is achieved at low applied voltages (≤7.9 V). In contrast, the highest sensitivity to NO2 is observed at high applied voltages. The response and recovery times and temporal drift of ε(κ)‐Ga2O3 characteristics under different ambient are estimated. Polycrystalline ε(κ)‐Ga2O3 exhibits the semiconducting mechanism of electron transport at high temperatures. A qualitative model of the gas‐sensing effect based on the modulation of electron concentration near the surface region of ε(κ)‐Ga2O3 due to the chemisorption of gas molecules is described. Tin doping of ε(κ)‐Ga2O3 increases the response to H2 at the temperature range from 25 to 550 °C.

Evaluation of phase, morphological, optical and electrical properties of microwave synthesized Sn doped CdO nanostructures

Microwave irradiation was used to create Sn-(5%, 10%, and 15%) doped CdO nanostructures. XRD, FTIR, UV–vis spectra, SEM, EDX, and TEM were used to investigate structural, vibrational, surface morphological, and optical properties of CdO and Tin doped CdO nanostructures. The phase and structure of pure and Tin doped nanostructures are verified by the XRD profile. Debye Scherrer's method was used to measure the mean crystallite sizes of CdO and Tin doped CdO nanostructures. It shows that as the concentration of Sn doping increases, the crystallite size decreases. SEM was used to observe the impact of Tin doping on surface morphology. EDX confirms the existence of Sn, Cd, and O elements in all of the samples. The presence of chemical bonding in various nanostructures is confirmed by a Fourier transform infrared spectrum. With more Sn doping, the optical band gap varied from 1.94 to 1.69 eV. The electric measurement was carried out for all the samples using Hall setup and two probe methods. CdO doped with 10% of Sn samples exhibits better electrical property than the other samples.

The microstructure of the rapidly solidified foil of the hypoeutectic alloy Sn – 4.4 wt. % Zn

The article presents the results of a study of the microstructure of the rapidly solidified foil of the hypoeutectic alloy Sn – 4.4 wt. % Zn. It was found that the investigated alloy has a two-phase structure, which consists of solid solutions of tin and zinc. Doping of tin with zinc leads to a decrease in the unit cell parameter. The difference between the unit cell parameters of a rapidly solidified alloy in comparison with an alloy of pure tin tends to decrease during holding, which is due to strong supercooling of the melt during its production at ultrahigh speeds, and the formation of a supersaturated solid solution of zinc in tin, which, due to high homological temperatures, as a consequence, active diffusion processes, decomposes at room temperature. It has been established that a microcrystalline structure is formed in the foil of the alloy under study, in the cross section of which there are uniformly distributed equiaxed dispersed dark zinc precipitates against the background of a light tin matrix; the absence of zinc plates in the foil reduces the ability to brittle fracture. The unequal distribution of the average chord of random secants on the grains in the surface layers A is caused by the release of heat, which leads to a decrease in the supercooling of the subsequent layers of the melt, and an increase in the grain size as the crystallisation front moves. It was found that in the (301) plane along the [103] direction, tin twinning is observed, which occurs under the action of quenching stresses at high crystallisation rates. The alloy under study has a (100) tin texture, the formation of which is associated with the fact that the (100) plane is the most densely packed, which promotes the growth of grains with this orientation at the highest rate.

Influence of tin (Sn) doping on Co3O4 for enhanced photocatalytic dye degradation

Wastewater remediation is one of the special issues that have been discussed in recent years and one of the main pollutants was dyes which totally changes the water behavior. To eradicate the organic compounds from the wastewater and reuse it, there are numerous steps have been taken into consideration. Dye degradation via photocatalysis is one of the promising technique with good efficiency. Pure and tin (Sn) doped Co3O4 was prepared employing co-precipitation technique. The structural, vibrational, optical and morphological analysis was done employing X-ray diffraction studies, Photoluminescence, Raman analysis and Scanning Electron Microscopic (SEM) studies. The well-defined nanoparticles were grown with 1 M Sn doped Co3O4. The photocatalytic activities of methylene blue dye under visible light were investigated by adding the samples (CS-1, CS-2, CS-3). 1 M Sn doped Co3O4 sample showed 75% efficiency towards dye degradation. The prepared 1 M Sn doped Co3O4 sample will be the best for photocatalytic activity. By doping Sn atoms the efficiency of the host is increased which will be the most promising candidate for the photocatalytic dye degradation applications.

Electronic structure modulation of CoSe2 nanowire arrays by tin doping toward efficient hydrogen evolution

The development of highly active, durable and earth-abundant electrocatalysts toward hydrogen evolution reaction (HER) is of great significance for promoting hydrogen energy. As one of the most potential substitutes for Pt-based materials, pyrite cobalt selenide (CoSe2) still has shortcomings in terms of HER performance possibly due to its unfavorable hydrogen adsorption characteristics. Metal cation doping has been considered as one of the most available methods to modulate the electronic structure of electrocatalysts. Herein, non-transition metal tin (Sn) doped CoSe2 nanowire arrays grown on carbon cloth have been constructed and fabricated via a simple gas-phase selenization treatment of hydroxide precursor. The successful doping of Sn element into CoSe2 nanowires was confirmed by many experimental results. The as-prepared catalyst shows an obviously enhanced HER performance in alkaline media. Compared with pristine CoSe2, the overpotential of Sn doped catalyst with optimal doping content decreases from 189 mV to 117 mV at 10 mA cm−2 and the Tafel slope declines from 94 mV dec−1 to 86 mV dec−1, as well as shows long-term durability for 100 h. Experimental results and further density functional theory (DFT) calculations show that Sn doping can improve the ability of charge transfer and increase the electrochemical surface area, as well as optimize the hydrogen adsorption energy, all of which are instrumental in HER performance improvement. This work not only provides atomic-level insight into regulating the electronic structure of transition metal selenides by main group metal doping, but also broadens the avenue of developing high-efficiency and stable non-precious metal catalysts.

Fabrication and characterization of p-Si/n-In2O3 and p-Si/n-ITO junction diodes for optoelectronic device applications

Octahedral novel indium tin oxide (ITO) films were fabricated on glass substrates. The dopant material tin (Sn) was added at different concentration like 0, 5, 10, 15 weight percentage (wt.%) with indium oxide precursor and the synthesis was done by spray pyrolysis technique. XRD studies revealed proper doping of tin in indium oxide crystal lattice structure. The surface morphology of ITO films confirmed the octahedral structure of crystallites formed and the variation in size of the microstructures with doping concentration. The bonding states of indium and tin with oxygen and composition of ITO films were inspected through XPS. The average roughness of films varied from 26.65 to 139.08 nm. The optical properties studied from UV-VIS studies showed a sharp increase in bandgap from undoped to 5 wt.% Sn doped indium oxide films followed by slight decrease in values with the increase in doping concentration. The photoluminescence excitation of ITO films showed a rapid fall in the peak intensity values due to the quenching of oxygen vacancies and a slight blue shift in emission confirms the doping of tin indium oxide. The resistivity values tremendously decrease with increase in doping concentration, that is tin doping improves conduction which was observed using two probe method. The fabricated p-Si/n-ITO junction diode shows that the ITO is degenerated semiconductor and the photo response is exhibited with a high ideality factor of 8.98 in dark and 6.46 in visible light exposed conditions respectively.

Activating sulfur sites of CoS2 electrocatalysts through tin doping for hydrogen evolution reaction

Exploring high efficient transition-metal dichalcogenides catalysts for hydrogen evolution reaction (HER) is important for water-derived hydrogen fuel. Pyrite cobalt disulfide (CoS2) is one of the potential HER catalysts due to its low price and inherent metallicity, but its catalytic activity is still unsatisfactory possibly attributed to the S sites with catalytic inert; hydrogen adsorption on S sites is weak extremely. Metal cation doping has been considered as one of the most available methods to modulate the electronic structure of electrocatalysts. Here, we report non-transition metal tin (Sn) doped CoS2 nanowire arrays grown on carbon cloth (Sn-CoS2/CC) as available catalysts for HER. The Sn-CoS2/CC catalyst with optimal doping concentration not only has an enhanced over potential of 161 mV at 10 mA cm−2, and the Tafel slope is 94 mV dec-1, but also shows good long-term durability in 32 h of testing. Experimental results and further density functional theory (DFT) calculations show that Sn doping can improve the charge transfer ability, enhance electronic conductivity, and arouse the catalytic insert S sites with optimal hydrogen adsorption free energy (ΔGH*). This work investigates a new method to activate the inert sites in metal-compound catalysts for water splitting and beyond through non-transition metal doping.

The effect of tin doping level on the physical properties and photocatalytic degradation of cadmium oxide nanostructured film

Pure and tin (Sn) doped CdO films were deposited onto soda-lime glass via ultrasonic spray pyrolysis (USP) method with Sn concentrations of 1, 2 and 3%. The effect of doping level on the structural, morphological and optical properties of the films was explored by using several diagnostic techniques including X-ray diffraction, atomic force microscopy, UV–Vis spectroscopy and Hall effect methods. The doping level in the CdO film affects the photocatalytic performance of the nanostructured films. It has been declared that the physical properties of the highly conducting and transparent nanostructured CdO films can be modified/controlled by tin doping for optoelectronic applications.

Highly dispersed Pt atoms and clusters on hydroxylated indium tin oxide: a view from first-principles calculations

First-principles simulations show that Pt single atoms and dimers are stabilized by tin doping in indium oxide and by the presence of hydroxyl groups.

Effect of tin doping on optical properties of ZnO thin films grown on glass substrate

The optical properties of synthesized zinc oxide films doped with tin in different concentrations (0-5 mol.%) were studied. X-ray diffraction revealed that the main phase of the obtained films is ZnO (wurzite). According to SEM data, the film consists of nanocrystallites, which are 10-20 nm in size. It was shown that the introduction of 0.5 mol.% tin ions leads to an increasing in the absorption of wavelengths (in the range of 300-370 nm) and a slight narrowing of the band gap.

Structural, optical and electrical transport properties of Sn doped In2O3

Present study focuses on the structural, morphological, optical and electrical transport properties of Sn substituted In2O3 (In2-x SnxO3; 0.0 ≤ x ≤ 0.25) synthesized by solid state reaction method. X-ray diffraction patterns and selected area electron diffraction from high resolution transmission electron microscopy substantiated the pure cubic bixbyite structure with high crystallinity. Raman analysis confirmed the cubic like phonon modes in each sample and their noticeable phase was revealed by the presence of tin doping. The band gap widening of all nanocrystalline samples were well explained by Burstein-Moss model, due to the filling of the strongly dispersing conduction band by doped electrons and the decrease in oxygen vacancies were confirmed by deconvoluted emission spectra. Hall measurements showed the n-type conductivity with low electrical resistivity (1.3011×10−4Ω-cm) along with high carrier concentration (7.523×1020cm−3), mobility (63.85 cm2/V-s) and electron mean free path (11.183 nm) for x = 0.1, optimizing it as a suitable candidate for optoelectronic applications.

In situ tuning of band gap of Sn doped composite for sustained photocatalytic hydrogen generation under visible light irradiation

The significance of Sn dopant on the photocatalytic performance of Iron/Titanium nanocomposite towards photocatalytic hydrogen generation by water splitting reaction is investigated. Iron/Titanium nanocomposite modified by Sn4+ dopant acts as a suitable photocatalyst for induced visible light absorption facilitating pronounced charge separation efficiency. Various characterization techniques reveal the heterojunction formation of hematite Fe2O3 with anatase - rutile mixed phase of TiO2 employing Sn doping, where Sn4+ dopant accomplishes the phase transformation of anatase to rutile, entering into the TiO2 lattice. This extended the lifetime of photogenerated charge carriers and enhanced the quantum efficiency of the photocatalyst. The band gap of the nanocomposite is tuned to ~2.4 eV, favoring visible light absorption. A hydrogen generation activity of 1102.8 μmol, approximately five times higher than the lone system (216.5 μmol) is achieved for the 5% Sn doped system for an average of 5 h. Heterojunctions of hematite with anatase-rutile mixed phase, generated as a consequence of tin doping facilitated the enhanced hydrogen generation activity of photocatalyst.

Electron Beam Infrared Nano-Ellipsometry of Individual Indium Tin Oxide Nanocrystals.

Leveraging recent advances in electron energy monochromation and aberration correction, we record the spatially resolved infrared plasmon spectrum of individual tin-doped indium oxide nanocrystals using electron energy-loss spectroscopy (EELS). Both surface and bulk plasmon responses are measured as a function of tin doping concentration from 1-10 atomic percent. These results are compared to theoretical models, which elucidate the spectral detuning of the same surface plasmon resonance feature when measured from aloof and penetrating probe geometries. We additionally demonstrate a unique approach to retrieving the fundamental dielectric parameters of individual semiconductor nanocrystals via EELS. This method, devoid from ensemble averaging, illustrates the potential for electron-beam ellipsometry measurements on materials that cannot be prepared in bulk form or as thin films.

Effects of Sn doping on the manufacturing, performance and carbon deposition of Ni/ScSZ cells in solid oxide fuel cells

This work demonstrates the effect of tin (Sn) doping on the manufacturing, electrochemical performance, and carbon deposition in dry biogas-fuelled solid oxide fuel cells (SOFCs). Sn doping via blending in technique alters the rheology of tape casting slurry and increases the Ni/ScSZ anode porosity. In contrast to the undoped Ni/ScSZ cells, where open-circuit voltage (OCV) drops in biogas, Sn–Ni/ScSZ SOFC OCV increases by 3%. The maximum power densities in biogas are 0.116, 0.211, 0.263, and 0.314 W/cm2 for undoped Ni/ScSZ, undoped Ni/ScSZ with 3 wt% pore former, Sn–Ni/ScSZ and Sn–NiScSZ with 1 wt% pore former, respectively. Sn–Ni/ScSZ reduces the effect of the drop in the maximum power densities by 26%–36% with the fuel switch. A 1.28–2.24-fold higher amount of carbon is detected on the Sn–Ni/ScSZ samples despite the better electrochemical performance, which may reflect an enhanced methane decomposition reaction.

The effect of Sn-doping on optical, electrical and morphological properties of spray-pyrolysed ZnO films

The present work has investigated the effects of tin doping on morphological and optical-electrical properties of zinc oxide films produced by spray-pyrolysis technique. The films exhibited droplet impact marks along the surface. Top-view micrographs disclosed black clusters of non-decomposed salts after tin doing. These morphological aspects have not compromised optical performance although they may have contributed to the rise in electrical resistivity due to charge scattering on the surface. Electrical conductivity was lowered as tin-doping concentration increased. Tin ions occupied interstitial sites in the host matrix and acted as conventional defects. The film transmittance at 550 nm was not significantly affected by tin doping, yet a slight loss in transparency was observed after 1 at. % Sn doping. Optical bandgap was reduced from 3.25 to 3.16 eV due to deep states when doping with 1 at. % Sn. The optical bandgap widened to 3.23 eV with incorporation of 2 at. % Sn. This behaviour is attributed to the Burstein-Moss effect.

Fabrication and characterization of solution processed Al/Sn:ZnO/p-Si photodiodes

This study describes the deposition of ZnO thin films with various Sn doping concentration by a solution-based spin coating method. The effect of Sn doping on structural ZnO thin films and optoelectrical features of ZnO based photodiodes have been investigated. As a result of the structural analysis by XRD and AFM, the thin films showed an amorphous nature and the surface roughness decreasing with Sn doping. The electrical analysis revealed that the fabricated diodes showed a high rectification ratio (RR). The maximum RR value of 4.38 × 104 at ± 4 V and minimum reverse bias current were obtained from SZO10 (%10 Sn doped ZnO). Also, all diodes indicated good photodiode characteristic and the highest responsivity value of 1.68 A/W was obtained from SZO10 as the result of photosensitivity. The obtained results showed that the tin doping improved the electrical and optoelectrical characteristics of the ZnO based diode.

Anticandidal and In vitro Anti-Proliferative Activity of Sonochemically synthesized Indium Tin Oxide Nanoparticles

The present work demonstrates the synthesis, characterization and biological activities of different concentrations of tin doped indium oxide nanoparticles (Sn doped In2O3 NPs), i.e., (Sn/In = 5%, 10% and 15%). We have synthesized different size (38.11 nm, 18.46 nm and 10.21 nm) of Sn doped In2O3 NPs. by using an ultra-sonication process. The Sn doped In2O3 NPs were characterized by by x-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) which confirmed the successful doping of tin (Sn) with Indium oxide (In2O3). Anticandidal activity was performed by standard agar dilution method using Candida albicans for the study. The minimum inhibitory/fungicidal concentration (MIC/MFC) values recorded were, 8 & >8 mg/ml for pure In2O3 NPs, 4 & 8 mg/ml for 5%, 2 & 8 mg/ml for 10%, whereas 1 & >4 mg/ml for 15% Sn doped In2O3 NPs, respectively. The topographical alteration caused by Sn doped In2O3 NPs on Candida cells, was clearly observed by SEM examination. A significant enhancement in anticandidal activity was seen, when Candida cells were exposed to (Sn/In = 5%, 10% and 15%). Moreover, we have also evaluated the impact of Sn-In2O3 NPs on human colorectal carcinoma cells (HCT-116). The results demonstrated that Sn-In2O3 NPs (Sn/In = 5%, 10% and 15%), caused dose dependent decrease in the cancer cell viability as the low dosage (2.0 mg/mL) showed 62.11% cell viability, while 4.0, 8.0, 16.0, 32.0 mg/mL dosages showed 20.45%, 18.25%, 16.58%, and 15.58% cell viability. In addition, the treatment of Sn-In2O3 NPs also showed significant cellular and anatomical changes in cancer cells as examined by microscopes. We have also examined the impact of Sn-In2O3 NPs (5%, 10%, 15%) on normal cells (HEK-293) and the results demonstrate that Sn-In2O3 NPs did not reduce the cell viability of normal cells.

Synthesis, Morphological, and Elemental Analysis of Pure and Tin Doped Chromium Oxide Nanoparticles

Objectives: To synthesize the pure and tin doped chromium oxide nanoparticles and analyzing the structural, morphological, and elemental composition of the prepared samples. Methods: Sn2+ doped chromium oxide (Cr2O3) nanoparticles are synthesized by microwave-assisted solvothermal method which is simple and cost effective. The pure as prepared sample was subjected to TG/DTA analysis. The impact of the added dopant (Sn2+) on the Cr2O3 nanoparticles was investigated by X-ray diffraction pattern, scanning electron microscopy, and Energy dispersive X-ray spectra. Findings/application: The synthesized tin doped chromium oxide nanoparticles were annealed at 700 ˚C for 2 h to enhance the crystalline quality and to obtain the desirable crystal phase. The annealed samples were found to be in rhombohedral structure and its average grain size decreases from 24 to 10 nm on increasing the dopant concentration. The scanning electron micrograph corroborates that the prepared nanoparticles are mostly spherical in shape. The Energy dispersive X-ray spectra ensure the presence of Cr, O, and Sn. This study has proven that the particle size will be tuned by increasing the concentration of Sn2+ in pure Cr2O3 nanoparticles. The Cr2O3 nanoparticles are mainly used in paints and pigments, the reduction in size increases the coating performance such as scratch resistance, hardness, and UV resistance. Keywords: Chromium Oxide, Solvothermal Method, X-ray Diffraction Pattern, Scanning Electron Microscopy, Rhombohedral, Energy Dispersive X-ray Spectra.