Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these compounds.During the synthesis of In_(2)O_(3),intermediate products In(OH)_(3)and InOOH are formed,which are the precursors of stable cubic(c-In_(2)O_(3))and metastable rhombohedral(rh-In_(2)O_(3))phases,respectively.A transition from c-In_(2)O_(3)to rh-In_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-In_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-In_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-In_(2)O_(3).The reverse situation is observed in composites based on c-In_(2)O_(3).Compared to In_(2)O_(3)and CeO_(2)–In_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between In_(2)O_(3)and CeO_(2).

Preparation of indium tin oxide targets with a high density and single phase structure by normal pressure sintering process

The present work mainly describes the technology for preparing indium-tin oxide （ITO） targets by cold isostatic pressing （CIP） and normal pressure sintering process. ITO powders were produced by chemical co-precipitation and shaped into an ITO green compact with a relative density of 60% by CIP under 300 MPa. Then, an ITO target with a relative density larger than 99.6% was obtained by sintering this green compact at 1550℃ for 8 h. The effects of forming pressure, sintering temperature and sintering time on the density of the target were inves- tigated. Also, a discussion was made on the sintering atmosphere.

Indium recovery from zinc oxide flue dust by oxidative pressure leaching

Indium was recovered from zinc oxide flue dust(ZOFD)with sulfuric acid by oxidative pressure leaching in an autoclave, and the effects of different technological conditions on indium leaching were studied.Potassium permanganate and hydrogen peroxide were used as oxidants.The atmospheric pressure leaching experiments were also carried out.The experimental results show that the leaching rate of indium can be effectively improved by oxidative pressure leaching.The optimum conditions of pressure leaching are determined as sulfuric 5.10 mol/L acid,leaching time 150 min,temperature 90℃,and the H2O2 dosage of 0.5 mL/g or 2.5%KMnO4.The leaching rate of indium is more than 90%,which is increased by 13%compared with that of atmospheric pressure leaching process without oxidant under the optimum conditions.

The feasibility study of the indium oxide supported silver catalyst for selective hydrogenation of CO_(2)to methanol

Silver catalyst has been extensively investigated for photocatalytic and electrochemical CO_(2) reduction.However,its high activity for selective hydrogenation of CO_(2) to methanol has not been confirmed.Here,the feasibility of the indium oxide supported silver catalyst was investigated for CO_(2) hydrogenation to methanol by the density functional theoretical(DFT)study and then by the experimental investigation.The DFT study shows there exists an intense Ag-In_(2)O_(3) interaction,which causes silver to be positively charged.The positively charged Ag species changes the electronic structure of the metal,facilitates the formation of the Ag-In_(2)O_(3) interfacial site for activation and dissociation of carbon dioxide.The promoted CO_(2) dissociation leads to the enhanced methanol synthesis via the CO hydrogenation route as CO_(2)^(*)→CO^(*)→HCO^(*)→H_(2)CO^(*)→H_(3)CO^(*)→H_(3)COH^(*).The Ag/In_(2)O_(3)catalyst was then prepared using the deposition-precipitation method.The experimental study confirms the theoretical prediction.The methanol selectivity of CO_(2) hydrogenation on Ag/In_(2)O_(3) reaches 100.0%at reaction temperature of 200℃.It remains more than 70.0%between 200 and 275℃.At 300℃and 5 MPa,the methanol selectivity still keeps 58.2%with a CO_(2) conversion of 13.6%and a space-time yield(STY)of methanol of 0.453 g_(methanol)g_(cat)^(-1)h^(-1),which is the highest methanol STY ever reported for silver catalyst.The catalyst characterization confirms the intense Ag-In_(2)O_(3)interaction as well,which causes high Ag dispersion,increases and stabilizes the oxygen vacancies and creates the active Ag-In_(2)O_(3)interfacial site for the enhanced CO_(2)hydrogenation to methanol.

Temperature-dependent bias-stress-induced electrical instability of amorphous indium-gallium-zinc-oxide thin-film transistors

The time and temperature dependence of threshold voltage shift under positive-bias stress（PBS） and the following recovery process are investigated in amorphous indium-gallium-zinc-oxide（a-IGZO） thin-film transistors. It is found that the time dependence of threshold voltage shift can be well described by a stretched exponential equation in which the time constant τ is found to be temperature dependent. Based on Arrhenius plots, an average effective energy barrier Eτ stress= 0.72 eV for the PBS process and an average effective energy barrier Eτ recovery= 0.58 eV for the recovery process are extracted respectively. A charge trapping/detrapping model is used to explain the threshold voltage shift in both the PBS and the recovery process. The influence of gate bias stress on transistor performance is one of the most critical issues for practical device development.

Extracting indium and preparing ferric oxide for soft magnetic ferrite materials from zinc calcine reduction lixivium

A hydrometallurgical process for indium extraction and ferric oxide powder preparation for soft magnetic ferrite material was developed. Using reduction lixivium from high-acid reductive leaching of zinc oxide calcine as raw solution, copper and indium were firstly recovered by iron powder cementation and neutralization. The recovery ratios of Cu and In are 99% and 95%, respectively. Some harmful impurities that have negative influences on magnetic properties of soft magnetic ferrite material are deeply removed with sulfidization purification and neutral flocculation method. Under the optimum conditions, the content of impurities like Cu, Pb, As, Al in pure Zn-Fe sulfate solution are less than 0.004 g/L, but those of Cd, Si, Ca and Mg are relatively high. Finally, thermal precipitation of iron is carried out at 210 ℃ for 1.5 h. The precipitation ratio of Fe is 93.33%. Compared with the quality standard of ferric oxide for soft magnetic ferrite materials, the contents of Al and Mg in obtained ferric oxide powder meet the requirement of YHT1 level of ferric oxide, and those of Si, Ca meet the requirement of YHT3 level of ferric oxide. XRD and SEM characterizations confirm that the obtained sample is well-dispersed spindle spherule with regular a-Fe2O3 crystal structure. The length-to-diameter ratio ofa-Fe2O3 powder is （3-4）：1 with an average particle size of 0.5 μm.

Preparation of Indium Tin Oxide Films on Polycarbonate substrates by Radio-frequency Magnetron Sputtering

Indium tin oxide（ITO）thin films（100±10nm）were deposited on PC（polycarbonate）and glass substrates by rf（radio-frequency）mannetron spuutering.The oxygen content of the ITO films was changed by variation of the sputtering gas composition.All the other deposition parameters were kept constant.The sheet resistance.optical transmittance and microstructure of ITO films were investigated using a four-point probe.spectrophotometer,X-ray diffractometer（XRD）and atomic force microscope（AFM）.Sheet resistances for the ITO films with optical transmittance more than 75% on PC substrates varied from 40Ω/cm^2 to more than 104 Ω/cm^2 with increasing oxygen partial pressure from O to about 2%.The same tendeney of sheet resistances increasing with increasing oxygen partial pressure was observed on glass substrates.The X-ray diffraction data indicated polycrystalline filns with grain orientations predominantly along（440）and （422）directions.The intensities of （440）and （422）peaks increased slightly with the increase of oxygen partial pressure both on PC and glass substrates.The AFM images show that the ITO films on PC substrates were dense and uniform.The average grain size of the films was about 40nm.

Preparation of High Quality Indium Tin Oxide Film on a Microbial Cellulose Membrane Using Radio Frequency Magnetron Sputtering

Microbial cellulose （MC） membranes produced by Acetobacter xylinum NUST4.1,were used as flexible substrates for the fabrication of transparent indium tin oxide （ITO） electrodes.Transparent and conductive ITO thin films were deposited on MC membrane at room temperature using radio frequency （RF） magnetron sputtering.The optimum ITO deposition conditions were achieved by examining crystalline structure,surface morphology and op-toelectrical characteristics with X-ray diffraction （XRD）,scanning electron microscopy （SEM）,atomic force mi-croscopy （AFM）,and UV spectroscopy.The sheet resistance of the samples was measured with a four-point probe and the resistivity of the film was calculated.The results reveal that the preferred orientation of the deposited ITO crystals is strongly dependent upon with oxygen content （O2/Ar,volume ratio） in the sputtering chamber.And the ITO crystalline structure directly determines the conductivity of ITO-deposited films.High conductive [sheet resis-tance ～120 Ω·square-1 （Ω·sq-1）] and transparent （above 76%） ITO thin films （240 nm thick） were obtained with a moderate sputtering power （about 60 W） and with an oxygen flow rate of 0.25 ml·min-1 （sccm） during the deposi-tion.These results show that the ITO-MC electrodes can find their potential application in optoelectrical devices.

Electrical and optical properties of indium tin oxide/epoxy composite film

The electrical and optical properties of the indium tin oxide （ITO）/epoxy composite exhibit dramatic variations as functions of the ITO composition and ITO particle size. Sharp increases in the conductivity in the vicinity of a critical volume fraction have been found within the framework of percolation theory. A conductive and insulating transition model is extracted by the ITO particle network in the SEM image, and verified by the resistivity dependence on the temperature. The dependence of the optical transmittance on the particle size was studied. Further decreasing the ITO particle size could further improve the percolation threshold and light transparency of the composite film.

Microstructure and properties of indium tin oxide thin films deposited by RF-magnetron sputtering

Tin-doped indium oxide （ITO） thin films were prepared using conventional radio frequency （RF） planar magnetron sputtering equipped with IR irradiation using a ceramic target of In2O3/SnO2 with a mass ratio of 1：1 at various IR irradiation temperatures T1 （from room temperature to 400℃）. The refractive index, deposited ratio, and resistivity are functions of the sputtering Ar gas pressure. The microstructure of ITO thin films is related to IR T1, the crystalline seeds appear at T1= 300℃, and the films are amorphous at the temperature ranging from 27℃ to 400℃. AFM investigation shows that the roughness value of peak-valley of ITO thin film （Rp-v） and the surface microstructure of rio thin films have a close relation with T1. The IR irradiation results in a widening value of band-gap energy due to Burstein-Moss effect and the maximum visible transmittance shifts toward a shorter wavelength along with a decrease in the film＇s refractive index. The plasma wavelength and the refractive index of ITO thin films are relative to the T1. XPS investigation shows that the photoelectrolytic properties can be deteriorated by the sub-oxides. The deterioration can be decreased by increasing the oxygen flow rote （fo2）, and the mole ratio of Sn/In in the samples reduces with an increase info2.

Effects of SiO_2 and TiO_2 on resistance stabilities of flexible indium-tin-oxide films prepared by ion assisted deposition

Inorganic buffer layers such as SiO2 or TiO2 and transparent conductive indium-tin-oxide （ITO） films were prepared on polyethylene terephthalate （PET） substrates by ion assisted deposition （IAD） at room temperature, and the effects of SiO2 and TiOzon the bending resistance performance of flexible ITO films were investigated. The results show that ITO films with SiO2 or TiO2 buffer layer have better resistance stabilities compared to ones without the buffer layer when the ITO films are inwards bent at a bending radius more than 1.2 cm and when the ITO films are outwards bent at a bending radius from 0.8 cm to 1.2 cm. 1TO films with SiO2 buffer layer have better resistance sta- bilities compared to ones with TiO2 buffer layer after the ITO fdms are bent several hundreds of cycles at the same bending radius, for the adhesion of SiO2 is stronger than that of TiO2. The compressive stress resulted from inward bending leads to the formation of more defects in the ITO films compared with the tensile stress arising from outward bending. SiO2 and TiO2 buffer layers can effectively improve the crystallinity of ITO films in （400）, （440） directions.

Dependence of Performance of Organic Light-emitting Devices on Sheet Resistance of Indium-tin-oxide Anodes

The dependence of the performance of organic light-emitting devices（OLEDs） on the sheet resistance of indiumtin-oxide（ITO） anodes was investigated by measuring the steady state current density brightness voltage characteristics and the electroluminescent spectra. The device with a higher sheet resistance anode shows a lower current density, a lower brightness level, and a higher operation voltage. The electroluminescence（EL） efficiencies of the devices with the same structure but different ITO anodes show more complicated differences. Furthermore, the shift of the light-emitting zone toward the anode was found when an anode with a higher sheet resistance was used. These performance differences are discussed and attributed to the reduction of hole injection and the increase in voltage drop over ITO anode with the increase in sheet resistance.

Transparent conducting indium-tin-oxide(ITO) film as full front electrode in Ⅲ–Ⅴ compound solar cell

The application of transparent conducting indium-tin-oxide （ITO） film as full front electrode replacing the conven- tional bus-bar metal electrode in III-V compound GalnP solar cell was proposed. A high-quality, non-rectifying contact between ITO and 10 nm N＋-GaAs contact layer was formed, which is benefiting from a high carrier concentration of the terrilium-doped N＋-GaAs layer, up to 2×10^19 cm^-3. A good device performance of the GalnP solar cell with the ITO electrode was observed. This result indicates a great potential of transparent conducting films in the future fabrication of larger area flexible III-V solar cell.

Low Temperature DC Sputtering Deposition on Indium-Tin Oxide Film and Its Application to Inverted Top-emitting Organic Light-emitting Diodes

Indium tin oxide （ITO） ultrathin films were prepared on glass substrate by DC （direct current） magnetron sputtering technique with the assistance of H2O vapor to avoid potential surface damage. The film properties were characterized by X-ray diffraction （XRD） technique, four-point probe method and spectrophotometer. The results show that the deposited ITO film with introduced H2O during sputtering process was almost amorphous. The average visible light transmission of 100 nm ITO film was around 85% and square resistivity was below 80 Ω/square. The film was used as the transparent anode to fabricate an inverted top-emitting organic light-emitting diodes （IT-OLEDs） with the structure of glass substrate/Alq3 （40 nm）/NPB （15 nm）/CuPc （x nm）/ITO anode （100 nm）, where the film thickness of CuPc was optimized. It was found that the luminance of this IT-OLEDs was improved from 25 cd/m^2 to more than 527 cd/m^2 by increasing the thickness of CuPc, and luminance efficiency of 0.24 lm/W at 100 cd/m^2 was obtained, which indicated that the optimized thickness of CuPc layer was around 15 nm.

Synthesis and sintering of indium tin oxide nanoparticles by citrate-nitrate combustion method

Spherical indium tin oxide （ITO） nanoparticles were synthesized by combustion method using citric acid as fuel and nitrates as oxidizer. The obtained ITO nanoparticles were characterized by TG-DSC, FT-IR, XRD, BET, TEM, and SEM. The ITO nanoparticles grew steadily with the increase of heat treatment temperature, and the 700~C calcined particles had a crystallite size of 25.3 nm and a specific surface area of 26.1 m2.g i The avoidance of chlorine ions in the synthesis process decreases particle agglomeration and promotes powder densification. The 900~C sintered pellet had a density of 67.6% of theoretical density （TD） and increased steadily to 97.3% for the 1400℃ sintered ceramics, respectively.

Effect of Sn^(4+) content on properties of indium tin oxide nanopowders

Indium tin oxide(ITO)nanopowders were prepared by a modified chemical co-precipitation process.The influence of different SnO2 contents on the decomposition behavior of ITO precursors,and on the phase and morphology of ITO precursors and ITO nanopowders were studied by X-ray diffractometry,transmission electron microscopy and differential thermal and thermogravimetry analysis methods.The TG-DSC curves show that the decomposition process of precursor precipitation is completed when the temperature is close to 600 ℃and the end temperature of decompositionis somewhat lower when the doping amount of SnO2 is increased.The XRD patterns indicate that the solubility limit of Sn4+ relates directly to the calcining temperature. When being calcined at 700℃,a single phase ITO powder with 15%SnO2(mass fraction)can be obtained.But,when the calcining temperature is higher than 800℃,the phase of SnO2 will appear in ITO nanopowders which contain more than 10%SnO2.The particle size of the ITO nanopowders is 15-25 nm.The ITO nanoparticles without Sn have a spherical shape,but their morphology moves towards an irregular shape when being doped with Sn4+.

Microstructure Study on Nano-phase Powder of Indium Tin Oxide

hemical co-precipitation method was used to prepare indium tin hydroxide. Indium tin hydroxide has the structure of cubic crystal. The cubic crystal structure transformed to amorphous after heat treatment at 250℃ for 1 h. When the heat treatment temperature was higher than 280℃, the amorphous transformed to cubic crystal structure. After heat treatment at 600℃ for 1 h, the particle size of indium tin oxide is 8～20 nm. The weight ratio of In∶Sn is near 9∶1. Its granule has spherical shape. The dispersity is good.

Enhanced performance in organic photovoltaic devices with a KMnO_4 solution treated indium tin oxide anode modification

The properties of poly（3-hexylthiophene）：（6,6）-phenyl C61 butyric acid methyl ester （P3HT：PCBM） organic pho- tovoltaic devices （OPVs） with an indium tin oxide （ITO） anode treated by a KMnO4 solution are investigated. The optimized KMnO4 solution has a concentration of 50 rag/L, and ITO is treated for 15 min. The modification of ITO anode results in an enhancement of the power conversion efficiency （PCE） of the device, which is responsible for the increase of the photocurrent. The performance enhancement is attributed to the work function modification of the ITO substrate through the strong oxygenation of KMnO4, and then the charge collection efficiency is improved.

Structural, electronic and vibrational properties of indium oxide clusters

Geometric, electronic and vibrational properties of the most stable and energetically favourable configurations of indium oxide clusters InmOn （1 ≤m, n ≤ 4） are investigated using density functional theory. The lowest energy geometries prefer the planar arrangement of the constituent atoms with a trend to maximize the number of ionic In-O bonds. Due to the charge transfer from In to O atoms, the electrostatic repulsion occurs between the atoms with the same kind of charge. The minimization of electrostatic repulsion and the maximization of In O bond number compete between each other and determine the location of the isometric total energy. The most stable linear In-O-In-O structure of In2O2 cluster is attributed to the reduced electrostatic repulsive energy at the expense of In-O bond number, while the lowest energy rhombus-like structure of In2O3 cluster reflects the maximized number of In O bonds. Furthermore, the vibrational frequencies of the lowest energy clusters are calculated and compared with the available experimental results. The energy gap and the charge density distribution for clusters with varying oxygen/indium ratio are also discussed.

Work Function Enhancement of Indium Tin Oxide via Oxygen Plasma Immersion Ion Implantation

Indium tin oxide （ITO） transparent conducting film was treated with oxygen plasma immersion ion implantation （PIII）. X-ray photoelectron spectroscopy （XPS） was employed to characterize the effect. The results suggested that the oxygen content in the surface was increased and maintained for more than 50 h compared with traditional plasma-treated samples. Meanwhile, the work function of ITO estimated by comparing the peak shift in the XPS diagram suggested a corresponding increase by more than 1 eV.