Optical Properties Of SnO Research Articles

Influence of Mg2+ Substitution for Sn4+ on Electronic Structure and Optical Properties of SnO2

First-principles calculation based on density functional theory (DFT) were employed to theoretically study the influence of partially replacing Sn4+ by Mg2+ on the electronic structure and optical properties of SnO2. The calculation results revealed that the Femi level shifted into the valence band, thereby indicating a p-type conductivity character. The energy band gap for SnO2 was found to be narrowed due to Mg2+ doping. Considering that the energy level for Mg 3s orbitals is comparable to that of O 2p orbitals, the localization behavior in the SnO2 valence band was modified. The imaginary part of dielectric functions' spectrum shifted towards lower energy after doping SnO2 with Mg2+, accompanied by an obvious redshift of the absorption edge. Furthermore, the absorption intensity for the doped systems was larger than that of pure SnO2 matrix in the low-energy region.

Revisit of the band gaps of rutile SnO2 and TiO2: a first-principles study

From the recent experimentally observed conduction band offset and previously reported band gaps, one may deduce that the valence band offset between rutile SnO2 and TiO2 is around 1 eV, with TiO2 having a higher valence band maximum. This implication sharply contradicts the fact that the two compounds have the same rutile structure and the Γ3+ VBM state is mostly an oxygen p state with a small amount of cation d character, thus one would expect that SnO2 and TiO2 should have small valence band offset. If the valence band offset between SnO2 and TiO2 is indeed small, one may question the correctness of the previously reported band gaps of SnO2 and TiO2. In this paper, using first-principles calculations with different levels of computational methods and functionals within the density functional theory, we reinvestigate the long-standing band gap problem for SnO2. Our analysis suggests that the fundamental band gap of SnO2 should be similar to that of TiO2, i.e., around 3.0 eV. This value is significantly smaller than the previously reported value of about 3.6 eV, which can be attributed as the optical band gap of this material. Similar to what has been found in In2O3, the discrepancy between the fundamental and optical gaps of SnO2 can be ascribed to the inversion symmetry of its crystal structure and the resultant dipole-forbidden transitions between its band edges. Our results are consistent with most of the optical and electrical measurements of the band gaps and band offset between SnO2 and TiO2, thus provide new understanding of the band structure and optical properties of SnO2. Experimental tests of our predictions are called for.

Determination of Semiconductor Type and Optical Properties of SnO2:F(FTO) and SnO2:In(ITO)

Determination of Semiconductor Type and Optical Properties of SnO2:F(FTO) and SnO2:In(ITO)

Significance of oxygen defects in SnO2 quantum dots as hybrid electrochemical capacitors

Understanding the role of defects is important due to its influence on electrical and optical properties of SnO2. This study reports the role of oxygen defects in SnO2 quantum dots decorated in carbon paper for an improved electron transfer process in electrochemical applications. A simple and cost-effective chemical route for preparation of a SnO2-decorated carbon paper electrode is described. The pseudo-capacitance property of SnO2nano-materials allowed strong improvement in capacitance value compared to pristine carbon paper. Transmission electron microscopy, Raman and photoluminescence studies reveal the presence of ultra-small SnO2 nanoparticles with defects related to prevalent oxygen vacancies. Electron paramagnetic resonance measurement indicates presence of singly charged defect in diamagnetic SnO2. Temperature-dependent photoluminescence, vibrational studies and electron energy loss spectroscopy provide further evidence for shallow in-plane oxygen defects in the SnO2 quantum dots, while impedance measurement discloses their significance in the electrochemical hybrid structure.

Electronic and optical properties of SnO2 (110)/MAPbI3 (100) interface by first-principles calculations

The interface structure, bonding energy, electronic properties and optical absorption properties of SnO2 (110)/MAPbI3 (100) interface were explored using the first-principles calculations. The lattice mismatch between SnO2 (110) and MAPbI3 (100) is 5.8%, and the interface structures were investigated in consideration of two different terminations with bonding energy about −0.79 J m−2 and −0.70 J m−2, respectively. Meanwhile, we found some interface states nearby the SnO2 (110)/MAPbI3 (100) interface. These interface states mainly come from 6s, 6p orbitals of Pb, 5p orbital of I and 2p orbital of O, which present on the first interface layers of MAPbI3 and SnO2.

Electronic structure and optical properties of SnO2:F from PBE0 hybrid functional calculations

The structural, electronic band structure and optical properties of SnO2 and SnO2:F are investigated as a function of fluorine (F) concentration by first-principles calculation using PBE0 hybrid exchange–correlation functional. Various supercells were constructed and optimized corresponding to different F content. An increase in the lattice parameters is obtained with increasing F level. Two different Sn–F bond lengths behavior are observed, where one of them is more sensible to F concentration. Lowdin charge analysis, related to charge transfer of Sn(0), Sn (1), O(5) and F(5), is presented and discussed, including the contribution of empty orbits 5d and 4f from Sn atoms. SnO2:F materials display characteristics of the n-type semiconductor, occupied states contributed mostly from hybridized Sn 5s, Sn 5p, O 2s and O 2p states in the conduction band increase with an increase in F concentration. Density of states (DOS) diagram of SnO2:F shows a band gap-like behavior inside the conduction band. The F dependence of the direct band gap, optical band gap, band gap-like and Burstein–Moss shift are calculated and discussed. A high concentration of fluorine (around 16 at.%) shows a transformation from direct to an indirect band gap. The imaginary dielectric function presents intra-band transition around Fermi level corresponding to Drude´s electrons. Also, inter-band transitions from valence band to conduction band and from occupied conduction band to unoccupied conduction band are evident from the optical spectra.

The Influence of Al and Zn Co-Doping on Optical and Structural Properties of Transparent and Conducting SnO2 Thin Films Prepared by Spray Pyrolysis Technique

The effect of Al and Zn Co-doping on the structural, electrical and optical properties of SnO₂ thin films have been studied. The undoped and aluminium and zinc co-doped SnO₂ nano crystalline thin films were prepared on glass substrates at 400 °C by spray pyrolysis technique. The starting material is (SnCl₄.5H₂O) and doping source are aluminium chloride and zinc chloride for tin (Sn), aluminium (Al) and zinc (Zn) respectively. The source materials have been dissolved in ethanol and stirred for four hours at 50 °C. The doping stoichiometric ratio was 4%. 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 film, Al and Zn Co-doped SnO₂ thin films have been characterized by different methods such as XRD, FESEM, UV-Vis NIR and EDAX analyses. The obtained results suggested that the prepared nanocrystalline thin films are suitable for gas sensor applications<div><br></div>

Increasing the Silicon Solar Cell Efficiency with Nanostructured SnO2 Anti-reflecting Coating Films

Thin films of fluorine doped nanostructured SnO2 were deposited on quartz glass and single crystal p-n silicon solar cell wafer by chemical spray pyrolysis. XRD measurements reveal that the synthesized films were polycrystalline in nature and showed preferred orientation along (110) plane. The average grain size of films was increased after doping. The morphological properties of films investigated by AFM measurements showed that the root mean square of surface roughness of the film has increased after doping.The optical properties of SnO2 and SnO2:F films were studied by recording the transmittance as a function of wavelength. The optical energy gap of SnO2 and SnO2:F films were found to be 3.62 eV and 3.75 eV, respectively. The efficiency of solar cell has been increased from 4.86% to 5.46% and to 6.06% after depositing with single layer of antireflected SnO2 and SnO2:F films, respectively.

An insight into the structural, electrical and optical properties of SnO 2 nanoparticles

Non stoichiometric SnO2 nanoparticles form an important class of materials which is a wide gap ( 3.64 eV), transparent, n-type semiconductor. It has a wide range of applications in the field of optics, electronics and catalysis. In this review article some reports on structural, electrical and optical aspects of these materials (pure and doped) have been discussed in detail. Results from XRD, SEM, TEM, and electron diffraction patterns have shown the structural features of these SnO2 nanoparticles. Electrical properties have been discussed with respect to carrier concentration and carrier mobility that ultimately effects the conductance in these materials. Particle size also play an important role. Optical properties are determined by direct energy band gap between conduction and valence band. Results from UV-vis spectroscopy (absorption, reflectance and transmittance) show the actual band gap in these materials. Direct measurement of the bad gap (Eg) from the intercept of the energy axis in Tauc Plots, show its dependence on the type of dopant and its concentration and also on particle size.

Influence of Hydrothermal Temperature on the Optical Properties of Er-Doped SnO2 Nanoparticles

This work reports on crystallization and optical properties of SnO2:Er3+ with a fixed Er3+ concentration of 0.25 at.%, prepared by the hydrothermal method. Crystal structure and morphology of the materials were studied by x-ray diffraction (XRD) and field emission transmission electron microscopy. Characteristic light emission at 1.5 μm for radiative 4 I 13/2 → 4 I 15/2 transitions within the 4f electron shell of Er3+ ions was studied by photoluminescence (PL) and excitation spectroscopy. The optical bandgap of the nanoparticles was examined by ultraviolet--visible absorption measurements. SnO2:Er3+ nanoparticles were formed in single-phase tetragonal rutile structure by applying temperatures ranging from 120°C to 200°C during the hydrothermal synthesis. An average crystal size of 5 nm was estimated by the Scherrer equation using the XRD data and found to be independent from the investigated hydrothermal temperatures. Whereas, the Er3+-related PL intensities were found to increase strongly with the hydrothermal temperature.

First-principles study of SnO under high pressure

This paper reports the first-principles study of SnO under high pressure within the generalized gradient approximation (GGA). We have calculated the structural, elastic, electronic and optical properties of SnO. The elastic properties such as the elastic constants [Formula: see text], bulk modulus, shear modulus, Young’s modulus, anisotropic factor, Pugh’s ratio and Poisson’s ratio are calculated and analyzed. Mechanical stability of SnO at all pressures is confirmed using the Born’s stability conditions in terms of [Formula: see text]. It is also found that SnO exhibits very high anisotropy. The energy band structure and density of states are also calculated and analyzed. The results show the semiconducting and metallic properties at zero and high pressures, respectively. Furthermore, the optical properties are also calculated. All the results are compared with those of SnO where available but most of the results at high pressure are not compared due to the unavailability of results.

Annealing Temperature Dependent Structural and Optical Properties of SnO&lt;SUB&gt;2&lt;/SUB&gt; Nanoparticles

Annealing Temperature Dependent Structural and Optical Properties of SnO&lt;SUB&gt;2&lt;/SUB&gt; Nanoparticles

Room temperature dilute magnetism in nanoscale Co and Zn co-doped SnO2

The influence of Co and Zn co-dopants, crystallite size and annealing temperature on the magnetic and optical properties of SnO2 were investigated. SnO2, Sn0.95Co0.025Zn0.025O2, Sn0.925Co0.05Zn0.025O2, Sn0.925Co0.025Zn0.05O2, Sn0.90Co0.05Zn0.05O2 and Sn0.85Co0.075Zn0.075O2, nanoparticles were synthesized by hydrothermal method. X-ray diffraction and Raman studies confirmed the single phase tetragonal crystal structure for all the investigated samples. The crystallite sizes were estimated to be in the range of 3–8 nm for the as synthesized samples and 20–25 nm for the samples annealed at 800 °C for 2 h. The photoluminescence, Raman and UV–Vis absorption spectroscopy studies revealed the presence of structural defects and possible oxygen vacancies in both the as synthesized and annealed samples. As synthesized undoped SnO2 sample exhibited the diamagnetic behavior at room temperature and all the Co and Zn co-doped samples exhibited the room temperature ferromagnetic (RTFM) behavior. RTFM along with the enhancement of saturation magnetization were observed for all the annealed samples. Interestingly, at room temperature the annealed samples exhibited the exchange bias effect.

Density Functional Theory Study on the Electronic Structure and Optical Properties of SnO2

Abstract The structure electronic and optical properties of rutile-type SnO2 were studied based on plane-wave pseudopotential density functional theory (DFT) adopting GGA, LDA, B3LYP and PBE0, respectively. The computing results show that the properties calculated by GGA and LDA are very close, which correspond to those by ultra-soft pseudopotential and norm conserving pseudopotential, respectively, and the properties calculated by B3LYP are near to those by PBE0. The band gap obtained from B3LYP and PBE0 is much more consistent with the available experimental data than that from GGA and LDA, whose band gap calculated by norm conserving pseudopotential is bigger than that by ultra-soft pseudopotential. However, the density of state and optical properties calculated from every type are basically similar in qualitative analysis, and the numerical values have a little difference. From the whole results calculated by the six methods, we can see that the structure, electronic and optical properties of rutile-type SnO2 calculated by B3LYP and PBEO are more near to the available experimental data than those by other methods.

Study of structural, morphological and optical properties of S and Cu co-doped SnO2 nanostructured thin films prepared by spray pyrolysis

Abstract We have established the effect of copper dopant concentration (Cu/Sn = 0–30 at.%) on the structural, morphological and optical properties of SnO2 : S films grown on glass substrate using a spray pyrolysis technique. According to the experimental evidence and data analysis, we found that the polycrystalline layers in undoped condition mainly consist of mixed phases such as SnS2 and SnO2, whilst in doped ones, Cu2SnS3 and Cu4SnS4 phases are dominant. With increasing Cu concentration, a decrease in the grain size with a change in the shape of the grains is observed. Optical measurement analysis showed that these films have a direct band gap energy of about 2.98–3.59 eV.

Computed electronic and optical properties of SnO2 under compressive stress

We consider the effects of three different types of applied compressive stress on the structural, electronic and optical properties of rutile SnO2. We use standard density functional theory (DFT) to determine the structural parameters. The effective masses and the electronic band gap, as well as their stress derivatives, are computed within both DFT and many-body perturbation theory (MBPT). The stress derivatives for the SnO2 direct band gap are determined to be 62, 38 and 25meV/GPa within MBPT for applied hydrostatic, biaxial and uniaxial stress, respectively. Compared to DFT, this is a clear improvement with respect to available experimental data. We also estimate the exciton binding energies and their stress coefficients and compute the absorption spectrum by solving the Bethe–Salpeter equation.

First-principles study of effects of Al doping on electronic structures and optical properties of SnO2

The electronic structures and optical properties of tin dioxide (SnO2) with different Al-doping concentrations (x = 0, 0·0185 and 0·0417) are investigated using the first-principles calculation of plane wave ultra-soft pseudo-potential technology based on the density functional theory under the local-density approximation. The results show that the Fermi level of Al-doped SnO2 goes into the valence band, indicating that Al-doped SnO2 is a typical p-type semiconductor. Moreover, with the increase in Al-doping concentrations, the band gap of SnO2 is broadened and the blueshift of the absorption spectrum becomes significant, which are in good agreement with the experiment results. In addition, the low reflectivity (<15%) in the visible light range is obtained.

Controllable synthesis and optical properties of SnO 2 core‐shell microspheres

SnO2 core-shell microspheres were synthesised via a hydrothermal method with hexamethylenetetramine as a surfactant. The structure and the morphology of the products were characterised by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. The results indicated that the overall dimension of the core-shell microspheres and the diameter of the spherical nuclei could be adjusted by changing the concentration of NaOH and hexamethylenetetramine or the reaction time. Based on the time dependent reactions, a possible growth mechanism is proposed. It is believed that the Kirkendall effect plays an important role in the formation of the core-shell structure. The optical properties of the core-shell structure microspheres were also studied through the photoluminescence and the Raman spectra.

EFFECT OF NOZZLE-SUBSTRATE DISTANCE ON ELECTRICAL, STRUCTURAL AND OPTICAL PROPERTIES OF SnO2 THIN FILMS PREPARED BY SPRAY PYROLYSIS

The physical, electrical and optical properties of SnO2 (TO) thin films deposited using spray pyrolysis technique at different nozzle-to-substrate distances were reported. The solutions consisted of diluted SnCl2.2H2O were sprayed on hot glass substrate which temperature was in 400±5 ˚C. X-ray diffraction (XRD), Uv-vis spectrophotometer and van der Pauw configuration studies had been performed on TO films coated on optical glass substrates. X-ray diffraction pattern revealed the presence of tetragonal crystal structure with (301) preferential orientation for all films. The grain size of the films varied from 23.78 nm to 29.74 nm at different nozzle- substrate distances. The film deposited at 40 cm nozzle-substrate distance had minimum sheet resistance of 3.233 Ω/cm2 and had maximum transmittance at 550 nm of 59.55 %. The best films deposited with optimum nozzle-to-substrate distance (NSD) of 40 cm.

Influence of manganese ions in the band gap of tin oxide nanoparticles: structure, microstructure and optical studies

This paper presents the joint effect of strain- and doping-induced band gap change in Sn1−xMnxO (0 ≤ x ≤ 0.05) nanoparticles. In addition, an effort was made to understand the effect of Mn doping on the structural and optical properties of SnO2. X-ray diffraction analysis showed a tetragonal structure and the unit cell volume decreased slightly with Mn4+ content. The Mn:SnO2 are spherical shaped particles with a size ranging from 7.7 to 13.8 nm as calculated by transmission electron microscopy, Scherrer's formula and Willamson–Hall plot. X-ray photoelectron spectroscopy showed clear evidence for tetragonal coordinated high-spin Mn4+ ions occupying the lattice sites of Sn4+ in the SnO2 host. Electron energy loss spectroscopy further confirmed composition and oxidation states of Sn4+ and Mn4+ ions. Manganese doping increased the band gap of SnO2 from 4 eV to 4.40 eV with Mn4+ concentration. Variation in band gap energy was attributed to the increasing lattice strain with Mn content and the charge transfer transitions between Mn4+ ions and conduction/valence bands of SnO2. Three photoluminescence emission bands observed at 320, 360 and 380 nm, when excited at 250 nm, proved Mn:SnO2 to exhibit good optical emission and to have potential application in nanoscale optoelectronic devices.