Oxidation Of Indium Research Articles

Corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey)

The effect of impurities on the electrical conductivity of aluminum has been studied in detail. The electrical conductivity of aluminum is 65.45% of that of copper. The tensile strength of aluminum wire is 150–170 MPa which, at equal conductivity, is about 65% of the strength of copper wire. This strength of aluminum wire is sufficient for bearing the wire’s own weight but may be too low in case of snow, ice or wind overloads. One way to improve the strength of aluminum wire is to use aluminum alloys having higher strength combined with sufficiently high electrical conductivity, e.g. the E-AlMgSi alloy (Aldrey). The key strengthening agent of the E-AlMgSi alloy (Aldrey) is the Mg2Si phase which imparts high mechanical strength to aluminum. In this work we present experimental data on the kinetics of high-temperature oxidation and electrochemical corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey). Thermal gravimetric study has shown that indium doping and high temperature exposure increase the oxidation rate of E-AlMgSi alloy (Aldrey), with the apparent alloy oxidation activation energy decreasing from 120.5 to 91.8 kJ/mole. Alloy oxidation rate data determined using a potentiostatic technique in NaCl electrolyte media have shown that the corrosion resistance of the indium doped alloy is 20–30% superior to that of the initial alloy. With an increase in NaCl electrolyte concentration the electrochemical potentials of the alloys decrease whereas the corrosion rate increases regardless of alloy composition.

Effect of indium incorporation, stimulated by UHV treatment, on the chemical, optical and electronic properties of ZnO thin film

Abstract We show the importance of powerful and complementary analysis techniques XPS (X-rays Photoelectron Spectroscopy), AES (Auger Electron Spectroscopy), and UPS (UV Photoelectron Spectroscopy) associated with PL (Photoluminescence) to investigate the chemical composition, optical emission, and electronic structure of undoped ZnO (UZO) and In-doped ZnO (IZO) thin films at the contaminated and clean states. The growth process of films on the Si substrate is achieved by ultrasonic spray pyrolysis. Both samples are submitted in the same conditions to cleaning treatment (argon ion etching followed by thermal annealing in Ultra High Vacuum UHV). The XPS and AES results display the great interest of physical UHV treatment to eliminate the contamination layer and stimulate the incorporation and oxidation of indium into the ZnO matrix. The PL measurements confirm that the UHV treatment allows the incorporation of indium into the ZnO matrix and eliminates wholly the visible emission due to hydroxyl impurities and defects such as oxygen interstitial and oxygen vacancies. The UPS technique is useful to show the electronic structure of the valence band and determine the work function, Fermi level, and the ionization potential of both samples.

Spontaneous template free growth of indium nano- and microwires via disproportionation of the InBr aqueous solution

We report a new approach to wet-chemistry growth of metallic indium microwires by disproportionation of the InBr aqueous solution. The microwires with characteristic diameter of 1 μm and length of more than 100 μm were obtained. We discuss the growth mechanism, according to which the reduction and oxidation of indium(I) ions take place on different facets of the growing crystal; the latter works as an electrochemical cell.

Surface Oxidation of Indium via Oxygen Ion Bombardment

Auger and X-ray photoelectron spectroscopy are used to analyze surface layers of indium bombarded with 200 eV (5 µA/cm2) oxygen ions. It is shown that after a solid-phase reaction, the indium atoms are in a chemically bound state with oxygen only on the surface.

Thermal Oxidation of Indium, Germanium, and Tin from Lead-Bearing Alloys Generated in Zinc Refinement

According to European regulations, indium and germanium are critical metals. Therefore, their recovery is a crucial issue. The present study was focused on the pyrometallurgical treatment of polymetallic PbSnIn and PbSnCuGeIn generated at the Miasteczko Zinc Smelter in order to recover In and Ge. The paper presents the production process of these alloys, as well as their characteristics. The materials were subjected to thermal processing in a laboratory-scale refining kettle fired with natural gas and air. Two different methods for the processing of the individual alloys are described. Two series (one for each material) consisting of five tests were performed in order to determine the optimal metal recovery parameters. The described pyrometallurgical process resulted in the production of an indium-enriched semi-product (In—1.15%) and a Ge–In-enriched product (Ge—11.1%, In—3.0%). Direct indium recovery rates were approximately 83% and >99%, respectively.

A Comparative Study on Fluorination and Oxidation of Indium–Gallium–Zinc Oxide Thin-Film Transistors

Both fluorination and oxidation have been employed to passivate defects in indium-gallium–zinc oxide thin-film transistors, leading to enhanced device attributes. It is presently reported that the former is more effective than the latter, requiring shorter process time (hence improved manufacturing efficiency), resulting in reduced initial defect population (hence enhanced scalability), and more robust resistance against process- and stress-induced defect generation (hence improved reliability). It is determined that the fluorine drive-in heat treatment is best conducted in an oxidizing atmosphere.

The oxidation and surface speciation of indium and indium oxides exposed to atmospheric oxidants

Metallic indium and its oxides are useful in electronics applications, in transparent conducting electrodes, as well as in electrocatalytic applications. In order to understand more fully the speciation of the indium and oxygen composition of the indium surface exposed to atmospheric oxidants, XPS, HREELS, and TPD were used to study the indium surface exposed to water, oxygen, and carbon dioxide. Clean In and authentic samples of In2O3 and In(OH)3 were examined with XPS to provide standard spectra. Indium was exposed to O2 and H2O, and the ratio of O2− to OH− in the O1s XPS region was used to monitor oxidation and speciation of the surface. HREELS and TPD indicate that water dissociates on the indium surface even at low temperature, and that In2O3 forms at higher temperatures. Initially, OH− is the major species at the surface. Pure In2O3 is also OH− terminated following water exposure. Ambient pressure XPS studies of water exposure to these surfaces suggest that high water pressures tend to passivate the surface, inhibiting extensive oxide formation.

Single step formation of indium and tin doped ZnO nanowires by thermal oxidation of indium–zinc and tin–zinc metal films: Growth and optical properties

Single step transformation of indium–zinc and tin–zinc films into doped ZnO nanowires is demonstrated. In and Sn doped ZnO nanowires are formed by the annealing of In–Zn and Sn–Zn bilayer films to 500°C in air. The nanowires of 15–100nm diameter and lengths up to 2µm are formed by the self-catalysis mechanism. Thus, by a single step annealing process doped ZnO nanowires can be realized. Independent of processing conditions all the nanostructures are polycrystalline as evidenced from x-ray diffraction patterns. The optical transmission, reflectance and absorption, in the wavelength range between 200 and 2500nm, have been measured as a function of annealing temperature. It is shown that all the bilayers and the In and Sn doped nanowires can be used as solar absorber materials due to their high absorption, low transmittance and reflectance, in this region of the spectrum. In certain cases, the nanowires exhibit high transmittance and very low reflectance making them very attractive for use as anti-reflection coatings.

Impact of environmental conditions on the chemical surface properties of Cu(In,Ga)(S,Se)2 thin-film solar cell absorbers

Environmentally driven aging effects play a crucial role in thin-film solar cells based on Cu(In,Ga)(S,Se)2, both for long-term stability and short air exposure during production. For a better understanding of such effects, Cu(In,Ga)(S,Se)2 absorber surfaces were investigated by x-ray photoelectron and Auger electron spectroscopy after exposure to different environmental conditions. Identical absorbers were stored in a nitrogen atmosphere, in damp heat, and under ambient conditions for up to 14 days. We find varying degrees of diffusion of sulfur, copper, and sodium towards the surface, with potential impact on the electronic surface structure (band gap) and the properties of the interface to a buffer layer in a solar cell device. Furthermore, we observe an oxidation (in decreasing order) of indium, copper, and selenium (but no oxidation of sulfur). And finally, varying amounts of carbon- and oxygen-containing adsorbates are found. In particular, the findings suggest that, for ambient air exposure, sodium carbonate is formed at the surface.

Continuous Shape Measure of electronic effect free steric distortions in tris(dithiocarbamato)indium(III): Synthesis, spectral, electrochemical, single crystal X-ray structural investigations and BVS calculations on tris(dithiocarbamato)indium(III) complexes

Geometrical distortions from an ideal octahedral geometry (iOh) towards an ideal trigonal prism (itp) in tris(dithiocarbamato)indium(III) complexes have been quantified by Continuous Shape Measure (CShM) analysis. Three tris(disubstituted dithiocarbamato)indium(III) complexes, cyclohexylmethyldithiocarbamate (chmdtc) (1), cyclohexylethyldithiocarbamate (chedtc) (2) and dicyclohexyldithiocarbamate (dchdtc) (3), have been prepared and characterized by spectral, cyclic voltammetric and single crystal X-ray structural techniques. The electronic effects are at a minimum for trivalent indium and the distortions follow the order: (3)>(1)>(2), as per the CShM values. The IR spectra indicate a contribution of the thioureide form of the dithiocarbamates to the stabilization of the compounds, with a characteristic C–N stretch in the range 1446–1475cm−1. 1H NMR spectra indicate that the protons in the vicinity of the thioureide nitrogen are the most affected on complexation. 13C NMR spectra showed the characteristic thioureide carbon signals at 201.18, 200.98 and 200.94ppm for complexes (1), (2) and (3) respectively. Cyclic voltammetric investigations revealed three single electron additions to the trivalent indium. The single crystal X-ray structures showed little change in the In–S and thioureide C–N bond distances or the S–In–S bite angles with changes in the steric demands, in the absence of any significant electronic effects. Bond Valence Sums (BVS) of the complexes identified the formal oxidation of indium to be +3 and the observed deviations show the increased covalent bonding. Nano indium sulfides have been prepared from the dithiocarbamates through a non-conventional solvothermal process. The nanosulfides have been characterized by SEM and EDX techniques. The ease and yield of formation follow the order: (3)>(1)>(2).

Nucleation Process of Indium on a Copper Electrode

ABSTRACT : The electrodeposition of indium onto a copper electrode from an aqueous sulfate solution contain-ing In 3+ was studied by means of cyclic voltammetry and chronoamperometry. Reduction and oxi-dation of indium on copper were investigated by using cyclic voltammograms at different negativelimiting potentials and at different scan rates in cumulative cycles. Cyclic voltammograms indicatedthat reduction and oxidation processes of indium could involve various reactions. Chronoamper-ometry was carried out to analyze the nucleation mechanism of indium in the early stage of indiumelectrodeposition. The non-dimensional plot of the current transients at different potentials showedthat the shape of the plot depended on the applied potential. The nucleation of indium at potentialstep of − 0.6~ 0.8 V was close to progressive nucleation limited by diffusion. However the non-dimensional plot of current transients for the indium nucleation showed different behaviors fromtheoretical curves at the potential step lower than

Effect of electron irradiation on the oxidation of indium

The oxidation kinetics of indium is studied for two cases, namely, during continuous electron irradiation (Ep = 1800 eV) and without electron irradiation, as a function of the time of exposure to an oxygen medium at a partial oxygen pressure of 10−4 Pa and room temperature. The initial oxygen exposure was 50 L. The kinetic curves recorded upon continuous electron irradiation have two inflection points, and they can be attributed to the following three states of oxidation: physical adsorption, chemisorption with the formation of a nonstoichiometric oxide layer, and the growth of a homogeneous oxide layer. Only the first inflection point is observed during oxidation without electron irradiation, and further exposure does not lead to the second inflection point within the experimental time.

Formation of In2O3 nanorings on Si substrates

A new approach to form the In2O3 nanorings (NRs) has been proven by tailoring the difference between property of metal and metal oxide. The formation process of the In2O3 NRs is proposed to be resulted form a subtle competition between the oxidation and evaporation of indium at the rim and center, respectively. Patterned In2O3 NRs have been grown on (001) Si substrates in combination with nanosphere lithography. The size and morphology of the NRs can be controlled by the size of polystyrene nanospheres and the thickness of indium layer. The optical property measurements showed that the In2O3 NRs are sensitive in absorption and emission of light between 600 and 622 nm in wavelength. The patterned In2O3 NRs on silicon are advantageous for fabricating optical-response photonic devices at the desired locations and direct integration to the silicon-based photonic devices with current processing technology.

The electron stimulated oxidation of indium in a vacuum

Auger electron spectroscopy was used to study electron stimulated adsorption from residual ultra-high vacuum medium on the atomically pure surface of indium. In the absence of irradiation of the surface of indium by a beam of electrons, adsorption processes were much weaker or almost absent. Electron stimulation considerably increased the rate of adsorption. Irradiation by electrons caused the dissociation of the adsorbate; as a result, a layer of carbon formed on the surface of indium. The conclusion is drawn that, in modeling electron stimulated adsorption, not only electronic excitation and/or dissociation of molecules in the gas phase, but also the excitation of surface particles or adsorbent defects should be taken into account.

Anodic behavior of indium in KOH solution

Cyclic voltammetry (CV) and X-ray diffraction (XRD) were used to investigate the anodic behavior of indium in a 3 M KOH solution on both rotating disc-platinum ring and static electrodes. Indium undergoes two processes in concentrated alkaline solution: activation and passivation. In the activation region, soluble, tri-valent indium is the main product, generated by the disproportionation reaction of In(OH)ad in the initial stage, and direct oxidation of indium during the latter stage. The soluble, tri-valent indium accumulates and precipitates as In(OH)3 on the electrode surface, inhibiting the oxidation of indium. In the resulting passivation region, the indium under the precipitated In(OH)3 is oxidized to In2O3, which is more stable than In(OH)3, and prevents further oxidation of the indium.

Oxidation and reduction behavior of pure indium

Fundamental knowledge on the oxidation behavior of pure indium, commonly used as a low-temperature, fluxless soldering material in micro-electro-mechanical system (MEMS) devices, is of importance as it influences the solder joint reliability. A thermodynamic model of the oxidation and reduction behavior of indium is developed by constructing an Ellingham diagram, and by using H2(g)reactions. Partial pressure (p) of H2O was shown to be the critical parameter in creating a reducing environment in the applicable solder reflow temperature range. Verification of the thermodynamic models was then carried out through heating and melting of indium in controlled glove box environments by adjustingp(H2)/p(H2O). The nanometer scale thickness of the oxide layer grown on indium was measured by a spectroscopic ellipsometer. The growth mechanism for oxidation in air below 220 °C follows Uhlig's logarithmic law where electron transport is the rate-controlling mechanism, implying that there is an incubation period for the onset of initial oxidation. Its activation energy was found to be 0.65 eV.

Study on Surface Modification of Indium Tin Oxide and Resist Surfaces Using CF4/O2 Plasma for Manufacturing Organic Light-Emitting Diodes by Inkjet Printing

We studied a surface modification technique for indium tin oxide (ITO) anodes without precleaning and resist banks for manufacturing organic light-emitting diodes (OLEDs) by inkjet printing. The ITO surface modified by inductively coupled plasma (ICP) with an optimized CF4/O2 (7:3) gas mixture improved both its hydrophilicity and its work function, while the resist surface treated by the plasma became hydrophobic. The resist and ITO surfaces treated by plasmas of various gas mixtures (i.e., CF4, CF4/Ar (1:2), CF4/O2 (x:1; x=1, 7/3, 4, and 9) were analyzed by X-ray photoelectron spectroscopy (XPS) of the C 1s, F 1s, O 1s, and In 3d5/2 core levels. On the uncleaned ITO surfaces modified by CF4/O2 plasmas, organic contaminants were removed more efficiently and the deposition of CFx on the remaining contaminants decreased with increasing oxygen. The amount of F in the form of InFx increased using the CF4/O2 (7:3) plasma in comparison with that using the CF4/Ar and CF4 plasmas. We investigated the effect of adding oxygen to CF4 on the change in gaseous species produced in the plasma chamber by mass spectrometry. In the CF4/O2 (7:3) plasma, the peak intensities of F+, HF+, F2+, O+, and O2+ were higher than those in the CF4 plasma. The results suggest that In2O3 was generated by the oxidation of indium with O, and InFx was generated by the fluoridation of indium with HF. By introducing InFx onto ITO surfaces using the CF4/O2 plasma, the hole-injection energy barrier could be reduced.

Phase composition and electrical conductivity of indium tungstate films produced from bilayer structures

Indium tungstate films have been synthesized via oxidation of indium and tungsten layers deposited on crystalline silicon and fused quartz substrates by magnetron sputtering. The structure and electrical properties of the films have been analyzed in relation to the oxidation procedure, which is shown to have a strong effect on the phase composition of the films. The dc conductivity of the films exhibits inverse Arrhenius behavior.

Observation of oxide precipitates in InN nanostructures

We observed the formation of oxide precipitates (bcc-In2O3) in InN nanostructures formed during metal-organic chemical vapor deposition (MOCVD) and/or subsequent postgrowth procedures in H2 ambient. It was found that InN is extremely unstable in H2 ambient and the activation energy of N2 desorption of InN is measured to be ∼0.28eV, which is one order of magnitude smaller than that of reported value of InN in vacuum. Instability of InN nanostructures under H2 ambient together with residual oxidant in the reactor facilitates the formation of indium oxide precipitates in the nanostructure matrix during MOCVD or the oxidation of residual indium at the surface, resulting in indium oxide dots.

In2O3/Si heterojunction solar cells fabricated by InN oxidation

The present paper reports on the fabrication of In 2 O 3 layers by oxidation of InN thin films deposited on n -type silicon substrate by magnetron reactive sputtering. The subsequent solar cells using the resulting In 2 O 3 /Si heterojunctions exhibit an ideality factor, deduced from current-voltage ( I – V ) characteristics of around 2.52 at a forward bias of 0.5 V. Other measured parameters were the short-circuit current ( I sc ), the open-circuit voltage ( V oc ), the maximum output power ( P m ), the fill factor ( FF ) and the efficiency ( η ), which had values of were 3.17 mA, 0.75 V, 0.869 mW, 0.365 and 9.66 %, respectively, under AM 1.5 illumination. The value of series resistance was around 107 Ω. In 2 O 3 films formed by the oxidation of InN have a higher open-circuit voltage than In 2 O 3 -based solar cells formed by the oxidation of indium.