Cadmium Tin Oxide Research Articles

Synthesis and Characterization of Cadmium Tin Oxide for MEMS Substrates and Its Comparative Computational Study with Silicon and Silicon Carbide

Synthesis and Characterization of Cadmium Tin Oxide for MEMS Substrates and Its Comparative Computational Study with Silicon and Silicon Carbide

CdO: SnO2 Composite UV-Assisted Room Temperature Ozone Sensor

Cadmium-tin oxide (CSO) thin films were fabricated by spray pyrolysis method at different substrate temperatures (Ts). The results showed a significant effect of Ts on the surface morphology and the electrical properties, which in turn has a significant effect on sensor gas sensitivity. The sample prepared at 400 °C appeared in the form of a donut shape, which has the best ozone sensitivity. No ozone sensitivity appeared in-dark, while showed good sensitivity when illuminated with UV at room temperature (RT). The study showed that the photon exposure method can substitute for the conventional method of sensors heating.

Self-assembled nanorods with reduced graphene oxide as efficient nano-catalyst for dual modality sensing of hazardous phenolic compound

The modern development in the agricultural production has huge influential factors being highly beneficial and also includes some health hazards. Under the class of chlorophenols, 2,4,6-trichlorophenol is a widely used chemical which remains as a major pollutant in the environment. The detection of 2,4,6-trichlorophenol was initiated as a controlling measure to decrease the seriousness prevailing in the ecosystem. The electrochemical and UV–vis absorption sensing platform are simple and low-cost detection techniques with precise and sensitive analysis. Cadmium tin oxide integrated with the reduced graphene oxide was employed as a nanohybrid for the construction of the working electrode. The structural and morphological analysis confirmed the high degree of crystallinity of the nanocomposite with nanorod formation. The high surface area, with high charge carrier mobility, and increased electrical conductivity of the material boosted the 2,4,6-trichlorophenol detection. The active surface area was calculated to be 0.068 cm−1, 0.089 cm−1, 0.118 cm−1 and 0.146 cm−1 for all the modified electrodes. The resistance of the electrodes was about 91.4 Ω, 72.9 Ω, 48.8 Ω and 41.6 Ω. The linear range of 2,4,6-trichlorophenol was 0.019 μM–0.299 μM and 1.299 μM–1678.97 μM in electrochemical sensing and 10.99 μM–24.84 μM in UV detection. The obtained limit of detection with the formulation 3σ/SD was about 3.05 nM and 80 nM with sensitivity about 14.01 μA μM−1 cm−2. The real sample detection in environmental real samples showed good recovery results. The specific selectivity, good repeatability, reproducibility and stability analysis proves the good sensing parameters. Thus, the fabricated electrode is highly sufficient of sensing 2,4,6-trichlorophenol. These excellent features of the material can be applied for several other applications which will provide good performances.

Cadmium Tin Oxide and Zinc Magnesium Oxide Prepared by Hollow Cathode Sputtering for CdTe Photovoltaics

ABSTRACTThis work reports the fabrication and characterization of superstrate-type Zn1-xMgxO/CdTe heterojunction solar cells on both CdxSnyO and commercial SnO2:F transparent conducting oxides (TCOs) in which the ZMO and CTO layers are produced for the first time by hollow cathode sputtering. The sputtering is conducted in a reactive mode using metal or alloyed metal targets fitted to a custom-made linear cathode. It is notable that the CdS buffer layer conventionally employed in CdTe solar cells is entirely replaced by the ZMO window layer. The use of ZMO is found to eliminate the blue loss associated with CdS optical absorption and further results in a higher open-circuit voltage. Key parameters were found to be the conduction band offset at the ZMO/CdTe interface and the ZMO thickness. It was discovered that the ZMO exhibits intense photoluminescence even at room temperature. Most of the solar cells were fabricated in the FTO/ZMO/CdTe configuration although CTO/ZMO/CdTe solar cells were also demonstrated. The CTO was produced with an electron mobility of 46 cm2 V-1s-1 without any post-deposition annealing or treatment.

Effective phototransformation in a heterostructure based on copper(I) oxide and cadmium tin oxide

We present a heterostructure consisting of anodic copper oxide Cu2O on a copper substrate and a transparent Cd–Sn–O conducting film for use in solar cells. Focusing on simplicity and the availability of film fabrication techniques, we chose anodic oxidation for forming the Cu2O film and the extraction-pyrolysis technique for forming the transparent Cd–Sn–O conducting layer. We demonstrate the possibility of considerable enhancement of the phototransformation efficiency in the Cu–Cu2O/Cd–Sn–O structure over this parameter in the Cu–Cu2O structure.

High-quality cadmium stannate annealed in N2 atmosphere for low-cost thin film solar cell

Radio frequency magnetron sputtered cadmium stannate (Cd2SnO4) or cadmium tin oxide (CTO) films were annealed in a nitrogen (N2) atmosphere.

Solar cell based on copper (I) oxide and cadmium tin oxide

As a solar cell a heterostructure has been proposed that consists of an anode copper oxide Cu2O and a transparent conductive layer Cd–Sn–O obtained via extraction-pyrolytic method. The heterostructure is formed on a copper substrate by means of anodic oxidation with further applying a transparent conductive oxide film. An increase in the efficiency of the Cu2O/Cd–Sn–O element compared with Cu–Cu2O structure has been shown to be possible.

Cadmium Stannate Films for Immobilization of Phospholipid Bilayers

Cadmium tin oxide (CTO) films on glass substrates were synthesized and functionalized by octadecyltrichlorosilane (OTS). CTO films were transparent with the bandgap of 2.92 eV. They exhibited n-type conductivity and carrier concentration of (3.31 ± 0.38) · 1019 cm−3. Weak temperature dependence points out to a nearly degenerative state of the carriers in the CTO films. Silanization by OTS yielded hydrophobic surface with the contact angle values reaching 103 ± 12 degrees. Silanization of films was followed by a significant reduction of the interfacial capacitance, which upon completion of the functionalization reached levels below 3 μF cm−2. The value of the electric capacitance as well as data of ATIR absorption, hints at sparse and disordered coverage of the CTO surface by octadecylalkylsilane molecules. Such organic layer, however, was able to trigger phospholipid (60% dioleoylphosphocholine and 40% cholesterol) vesicle rupture and the formation of a secondary layer of phospholipid, thus rendering hybrid bilayer surface construct. Such hybrid constructs may be useful in applications where electrode coupling to a model biological membranes and membrane bound proteins is required, such as biosensing and photovoltaics.

Sol-gel processing of highly transparent conducting Cd2SnO4thin films

Polycrystalline thin films of cadmium stannate (Cd2SnO4) (CTO) were coated on corning glass substrates by sol-gel method. The films were fired at different temperatures and annealed in inert ambient (N2) at 680°C. The structural, optical, and electrical properties of dip-coated cadmium-tin-oxide (CTO) thin films are discussed. CTO layers with a Hall mobility of 30 cm2/Vs and a carrier density of 1.4 × 1021 cm−3 resulting in a resistivity of 5 × 10−4 Ω cm have been deposited. Dip-coating conditions must be carefully monitored to produce consistent films. The high electronic conductivity is due to two effective mechanisms of n-type doping: (i) stoichiometric deviation and (ii) self-doping.

Effect of Heat Treatment on the Nanoscale Structure and Optical Properties of Cd<sub>2</sub>SnO<sub>4</sub> Thin Films Deposited by RF Magnetron Sputtering

Cadmium tin oxide Cd2SnO4 thin films with a thickness of 228.5 nm were prepared by RF magnetron sputtering technique on glass substrates at room temperature. AFM has been utilized to study the morphology of these films as a function of annealing temperature at the nanoscale. The optical properties of these films, such as the transmittance, T(λ), and reflectance, R(λ), have been studied as a function of annealing temperature. The optical constants, such as optical energy gap, width of the band tails of the localized states, refractive index, oscillatory energy, dispersion energy, real and imaginary parts of both dielectric constant and optical conductivity have been found to be affected by changing the annealing temperature of the films.

Optoelectronic properties of R-F magnetron sputtered Cadmium Tin Oxide (Cd2SnO4) thin films for CdS/CdTe thin film solar cell applications

The influence of substrate temperature on the microstructural behavior, optical, electrical properties and on the scattering mechanism of charge carriers were studied for the as-prepared radio-frequency (R-F) magnetron sputtered Cadmium Tin Oxide (Cd2SnO4) thin films. Films prepared at the substrate temperature of 300°C were found to be polycrystalline in nature with preferential orientation along (311) plane. Well pronounced Moss–Burstein shift, in the transmittance spectra with dispersions in the optical band gap from 3.07 to 3.30eV, was observed at substrate temperatures between 25 and 300°C. Optical property of high visible transmittance was retained by the films. Analysis of the electrical properties on the prepared crystalline Cd2SnO4 films showed a calculated resistivity of 10−3–10−4Ωcm, with n-type carrier density in the range of 1019–1020cm−3 and the charge carrier mobility in the range of 63–30cm2/Vs. The effects of structural, compositional and optical properties on the scattering mechanism of charge carrier are elaborated and reported to be an experimental evidence for the theoretical predictions. The results revealed the essential DC electrical conduction behavior, which is ideal for the fabrication of Cd2SnO4-based CdS/CdTe thin film solar cells.

Preparation and Crystal Structures of SomeAIVB2IIO4Compounds: Powder X-Ray Diffraction and Rietveld Analysis

TheAIVB2IIO4compounds such as cadmium tin oxide (Cd2SnO4or CTO) and zinc tin oxide (Zn2SnO4or ZTO) are synthesized by solid state reaction of the subsequent binary oxides. The synthesized powders were analyzed through the powder X-ray diffraction (PXRD). Cell search done on the PXRD patterns shows that the Cd2SnO4crystallizes in orthorhombic structure with space groupPbamand the cell parameters asa=5.568(2) Å,b=9.894(3) Å, andc=3.193(1) Å and the Zn2SnO4crystallizes as cubic with the space groupFd3 -mand with the cell parametera=8.660(2) Å. Rietveld refinement was done on the PXRD patterns to get the crystal structure of the Cd2SnO4and Zn2SnO4and to define the site deficiency of atoms which causes the electrical properties of the materials.

High Transmission and Low Resistivity Cadmium Tin Oxide Thin Films Deposited by Sol-Gel

ABSTRACTTransparent conducting cadmium tin oxide (CTO) thin films were obtained from a mixture of CdO and SnO2 precursor solutions by the dip-coating sol-gel technique. The thin films studied in this work were made with 7 coats (∼200 nm) on corning glass and quartz substrates. Each coating was deposited at a withdrawal speed of 2 cm/min, dried at 100°C for 1 hour and then sintered at 550°C for 1 hour in air. In order to decrease the resistivity values of the films, these were annealed in a vacuum atmosphere and another set of films were annealed in an Ar/CdS atmosphere. The annealing temperatures (Ta) were 450°C, 500°C and 550°C, as well as 600°C and 650°C, when corning glass and quartz substrates were used, respectively. X-Ray diffraction (XRD) patterns of the films annealed in a vacuum showed that there is only the presence of CTO crystals for 450°C≤ Ta ≤ 600°C and CTO+SnO2 crystals for Ta=650°C. The films annealed in Ar/CdS atmosphere were only constituted of CTO crystals independent of the Ta. The minimum resistivity value obtained was ∼4 x 10-4 Ωcm (Rsheet= 20 Ω/□) for the films deposited on quartz and annealed at Ta=600°C under an Ar/CdS atmosphere. The films deposited on quartz showed the higher optical transmission (∼90%) with respect to the films deposited on corning glass substrates (∼85%) in the Uv-vis region. For their optical and electrical characteristics, these films are good candidates as transparent electrodes in solar cells.

Orthorhombic/cubic Cd2SnO4nanojunctions: enhancing solar water splitting efficiency by the suppression of charge recombination

The low practical efficiency of binary metal oxide semiconductor-based photo-electrochemical (PEC) water splitting has prompted researchers to examine ternary and quaternary oxides, which provide more leverage for engineering the desired PEC properties via stoichiometry (valence) and phase control. One ternary system of interest in this context is cadmium tin oxide (Cd2SnO4), which supports the cubic and orthorhombic phases with optical, electronic and catalytic properties that are favourable for PEC water splitting. However, its practical PEC performance is limited by high surface recombination of the photogenerated charge carriers. In this work we circumvent this problem by engineering the constitution of Cd2SnO4 nanoparticles to a biphasic nanojunction form, comprising of a nanocomposite of cubic and orthorhombic phases. The favourable conduction band alignment between the cubic and orthorhombic phases leads to a dramatic reduction in the recombination of the photogenerated charges, leading to a 10-fold increase (from 250 μA cm2 to over 2 mA cm2) in the photocurrent vis-a-vis the single cubic or orthorhombic phase performance. We discuss the underlying mechanism for the observed dramatic enhancement in the water splitting efficiency.

Cadmium tin oxide thin films deposited by RF magnetron sputtering for photovoltaic applications

Cadmium tin oxide (CTO) thin films were deposited by radio frequency (RF) magnetron sputtering from a CdO:SnO2 target onto glass substrates at temperatures from ambient to 300°C. As-deposited films exhibited amorphous structure and high sheet resistance. Single phase cadmium stannate (Cd2SnO4) thin films with cubic spinel structure having both random and preferred orientation along (400) were obtained after annealing in Ar/CdS atmosphere. The randomly-oriented single phase Cd2SnO4 thin films showed a high mobility of >50cm2V−1s−1 and carrier density of ∼7×1020cm−3. The thermal expansion coefficient of Cd2SnO4 films was determined to be 5.6×10−6cm/cm/K. The dependence of optical and electrical properties of the as-deposited and annealed CTO thin films on oxygen content in the sputtering gas, substrate temperature and annealing temperature were reported. 16% (AM 1.5) conversion efficiency was achieved for CdTe thin film solar cells using Cd2SnO4 films as the window layer.

Quantum dot CdS coupled Cd2SnO4 photoanode with high photoelectrochemical water splitting efficiency

Quantum dot (QD) coupled wide band gap semiconductors such as TiO2 and ZnO have shown enhanced photoelectrochemical (in solar cells as well as water splitting) performance due to extended visible light absorption facilitated by QDs, compounded with favourable energetics for charge injection into the conduction band of the host semiconductor. In this work we investigate a new interesting system in this context, namely cadmium tin oxide (Cd2SnO4) coupled with CdS QDs. We find that the Cd2SnO4 photoanode, despite having a similar bandgap to that of CdS (2.2–2.5 eV), exhibits a very large (>40 fold) enhancement in the efficiency only when coupled to CdS QDs. By employing various microstructural, optoelectronic and photoelectrochemical characterization techniques we show that the favourable energetics and charge transport properties of Cd2SnO4 play the most crucial role in the enhancement of the photoelectrochemical performance. Our work suggests that it may be possible to design highly efficient photoelectrochemical systems by tailoring the constitution of nanocomposites based on the relatively less studied ternary oxide–sulphide heterosystems.

Investigation of hexadecanethiol self-assembled monolayers on cadmium tin oxide thin films

This study reports the use of variable angle reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy to investigate the formation of a 1-hexadecanethiol adlayer on cadmium tin oxide (CTO) thin film surfaces. These adlayers appear to be robust, ordered monolayers. The optical and electronic properties of CTO thin films chemically vapor deposited onto glass substrates were also investigated. The reflectance of the CTO films was dependent upon the incident angle of the impinging radiation and revealed a reflectance decrease indicative of a plasma frequency in the mid-IR using p-polarized radiation.

Transparent conducting oxide thin films of Cd 2SnO 4 prepared by RF magnetron co-sputtering of the constituent binary oxides

Thin films of cadmium tin oxide (Cd 2SnO 4) have been deposited on glass substrates by RF magnetron co-sputtering from cadmium oxide (CdO) and tin oxide (SnO 2) targets in an Argon ambient. Co-sputtering offers a means to control the atomic stoichiometry of Cd 2SnO 4, which influences the material's electro-optical and structural properties. The Cd 2SnO 4 films were deposited at room temperature and subsequently subjected to a heat treatment in inert or reducing (H 2) ambient. The as-deposited films were amorphous, and became polycrystalline after annealing at high temperatures. Using this method, Cd 2SnO 4 films with a Hall mobility of 32.3 cm 2 V −1 s −1 and a carrier concentration of 7.40×10 20 cm −3 corresponding to a resistivity of 2.07×10 −4 Ω cm have been prepared. The films exhibited average optical total transmission in excess of 90% in the visible region. The optical bandgap was found to be in the range of 2.97–3.18 eV, depending on post deposition treatment.

Properties of R.F. magnetron sputtered cadmium–tin–oxide and indium–tin–oxide thin films

The electrical, optical, structural, chemical, and etch properties of r.f. magnetron, sputter-deposited thin films of indium–tin–oxide (ITO) and cadmium–tin–oxide (CTO) are presented. Polycrystalline thin films of CTO and ITO with distinct diffraction peaks corresponding to the (220), (222), and (400) crystal planes and with an overall preferential 〈111〉 orientation were obtained at elevated deposition temperatures. The lattice parameter of these films was determined to be 0.948 and 1.026 nm for CTO and ITO, respectively. These thin films possess low resistivities in the 10 −4 Ω cm range, Hall mobilities up to 30 cm 2/V s, and carrier concentrations in the 10 20 cm −3 range. In excess of 85% of the perpendicularly incident optical radiation, in the 0.85 to 1.55 μm wavelength range, and up to 50% of the incident radiation at a wavelength of 365 nm was transmitted through the CTO and ITO conductors. A variety of wet and dry etching techniques were investigated in order to delineate features in the thin films. From investigations concerned with the Schottky and ohmic contact characteristics of CTO and ITO films deposited on undoped AlGaAs and InAlAs, ideality factors ranging from 1.1 to 1.2 and Schottky barrier heights ranging from 0.67 to 1.05 eV were obtained.

The properties of cadmium tin oxide thin-film compounds prepared by linear combinatorial synthesis

SnO 2 and CdO films with high electrical and optical quality have been produced by using low-pressure metal-organic chemical vapor deposition. Based on the knowledge gained from binary oxide formation, linear combinatorial synthesis is used to study the ternary oxide (Cd–Sn–O) compound. Compositional, structural, electrical, and optical properties of the films are found to vary along the reactant gas flow direction. The crystal structure indicates that the CdO-like films are formed near the location of gas injection and SnO 2-like films near the end of the deposition zone. As composition and structure change, the carrier concentration varies around 10 20 cm −3, and the mobility increases from less than 1 to ∼60 cm 2 V −1 s −1. The optical bandgap of the films also increases from ∼2.75 to 3.65 eV as composition moves from CdO-like films to SnO 2-like films.