Zn-doped In2O3 Research Articles

Resistance and transparency tunable Ag-inserted transparent InZnO films for capacitive touch screen panels

We have investigated sheet resistance and transparency tunable Zn-doped In2O3 (IZO) films through the insertion of a nano-size Ag layer for use as transparent electrodes for capacitive-type touch screen panels (TSPs). Due to the high conductivity of a nano-size Ag layer, the optimized IZO/Ag/IZO film showed the lowest resistivity of 3.69×10−5Ω-cm, even though it was sputtered at room temperature. The dependence of resistivity on temperature demonstrated that the electrical conductivity of the IZO/Ag/IZO is dominated by the nano-sized Ag metal layer. Furthermore, effective antireflection of the IZO/Ag/IZO at optimized Ag thickness (14nm) led to high optical transmittance of 85.16%, which is higher than that of conventional ITO films. Using optimized IZO/Ag/IZO with a sheet resistance of 5.27Ω/sq and an optical transmittance of 85.16% prepared on specially designed flexible substrate (Nepes glasslike film), we demonstrated capacitive TSPs. The operation of capacitive-type TSPs with IZO/Ag/IZO multilayer electrodes indicates that the IZO/Ag/IZO multilayer is a promising transparent electrode for large-area capacitive-type TSPs due to its low sheet resistance and high transparency when it is very thin.

Zn-doped In2O3nanostructures: preparation, structure and gas-sensing properties

Novel Zn-doped In2O3 nanocages and hollow spindle-like nanostructures (HSNs) have been prepared by calcining precursors obtained via a facile template-free hydrothermal method. The change in morphology, size, and phase compositions in a controlled synthesis of the Zn-doped In2O3 nanostructures are achieved by simple adjustments of the amount of water. The result of this formation mechanism investigation reveals that the amount of water and the reaction time make significant contributions to the growth of Zn-doped In2O3 nanostructures. The driving forces for the formation of the nanostructures are the precipitation–dissolution–renucleation–growth and Ostwald ripening processes based on time-dependent experimental results. The gas-sensing properties of Zn-doped In2O3 nanocages and HSNs have shown high sensitivity toward formaldehyde (HCHO) vapor at a relatively low operating temperature. Note that the gas sensor fabricated with Zn-doped In2O3 HSNs exhibit a higher and faster response than those fabricated with Zn-doped In2O3 nanocages due to the larger surface area and the decreasing size of the particle.

Transparent Zn-Doped In2O3 Electrode Prepared by Radio Frequency Facing Target Sputtering for Flexible Dye-Sensitized Solar Cells

For the application to transparent electrode in flexible dye-sensitized solar cells (DSSCs), Zn-doped In2O3 (In2O3:Zn) thin films have been fabricated on polyethylene naphthalate (PEN) substrate by the radio frequency facing target sputtering method, and their characteristics have been investigated as a function of deposition pressure. X-ray diffraction study reveal that the structure of In2O3:Zn thin films is amorphous nature. The film morphology is slightly sensitive to the deposition pressure. At the sputtering pressure of 0.40 Pa, In2O3:Zn thin film on PEN exhibits a sheet resistance of about 12.4 Ω/□ and average transmittance of about 85% at 550 nm wavelength, resulting in the highest value for figure of merit. The flexible DSSC device with the In2O3:Zn electrode shows the efficient solar-to-electrical power conversion efficiency (η), which is the maximum η value of 4.6% under simulated air mass 1.5 irradiation (100 mW/cm2).

Superconducting characteristics and microstructure of polycrystalline Zn-doped In2O3 films

In order to investigate the relation among the superconducting transition Tc, carrier density n, resistivity ρ and the microstructure in the polycrystalline (In2O3)1−x–(ZnO)x films, we prepared specimen films by post annealing of amorphous films with x=0.025 at various annealing temperature Ta and for annealing time ta=1h and 4h. As for microstructures, we have investigated the distribution of elements by scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). We have found followings: (1) The annealed films clearly show the superconductivity of which Tc depends on Ta, ta and n. This indicates that the superconductivity is determined by the combination of crystallinity and carrier density. (2) The data on STEM–EELS spectra mapping of indium plasmon indicate that droplets of the pure indium phase exist inside a film, where the distribution of these droplets dispersed. Therefore, it seems that droplets do not form an electrical conducting path, that is, it is possible that observed superconductivity is due to intrinsic characteristic of polycrystalline (In2O3)1−x–(ZnO)x films.

Highly conductive indium zinc oxide prepared by reactive magnetron cosputtering technique using indium and zinc metallic targets

Zn-doped In2O3 film is frequently deposited from an oxide target; but the use of metallic target is increasingly expected as preparing the film with comparable properties. This work aimed to prepare a highly conductive and transparent Zn-doped In2O3 thin film on Corning Eagle2000 glass substrate by magnetron cosputtering method using indium and zinc targets. Structural characterization was performed using x-ray diffraction and x-ray photoelectron spectroscopy. The film had an amorphous structure when the film was prepared on an unheated substrate, but had an In2O3 polycrystalline structure when the film was deposited on 150 and 300 °C substrates. The electrical properties of the film were greatly affected by annealing; the Zn-doped In2O3 film had a low resistivity of 6.1×10−4 Ω cm and an average transmittance of 81.7% when the film was deposited without substrate heating and followed a 600 °C annealing.

One-Dimensional Zn-Doped In2O3−SnO2 Superlattice Nanostructures

One-dimensional (1D) Zn-doped In2O3−SnO2 superlattice nanostructures have been fabricated on single-crystal silicon substrates by the layer-by-layer growth mode via the thermal chemical vapor transport and condensation with Au catalysts. The morphology, structure, and composition of the as-synthesized 1D superlattice were analyzed in detail. To exploit the potential applications of the fabricated nanostructures, the field emission properties of samples were characterized. The growth mechanism of the 1D Zn-doped In2O3−SnO2 superlattice nanostructures was discussed on the basis of the vapor−liquid−solid process.

Electrical transport properties of amorphous Zn-doped In2O3 films in a wide region of carrier density

We have systematically investigated the temperature dependence of resistivity p and Hall mobility μ of amorphous Zn-doped In2O3 films (350 nm) in the temperature range 2.0 to 300 K. We prepared film specimens with carrier density n ≈ (2 x 1017 − 6 x 1020/cm3) and p ≈ (3 − 4000)μΩcm (300 K) by changing the gas pressure of oxygen during DC-magnetron sputtering. The μ(n) shows the convex characteristic with a broad peak near n ≈ 3 x 1020cm3, taking the value μ ≊ 50cm2/Vs. In the low n region, it has been found that the μ seems to change as μ ∝ n1/3 . For films with n ≥ 5 x 1019/cm3, the p(T) shows the metallic behavior between ≈ 20 K and 300 K. On the other hand, for films with n ≤ 1019/cm3, p(T) essentially shows the insulating behavior at whole temperatures. From the analysis of the p(T) in the expression of p(T) = p0 exp(A/Tn) at low temperatures, we obtained that the data is well explained by n = 1/2 for dirty films. The estimated electron mean free path ℓ(4 K) deviates from the linear dependence of ℓ ∝ n to decease abruptly near ℓ ≈ 0.2 − 0.4 nm corresponding to the average distance between In and In (or oxygen).

Single zinc-doped indium oxide nanowire as driving transistor for organic light-emitting diode

Zn-doped In2O3 nanowires (NWs) were prepared by simple chemical vapor deposition and were systematically characterized. Field-effect transistors (FETs) constructed from the Zn-doped In2O3 nanowires exhibit excellent performance characteristics such as high mobility, “high-on-state” current of 105A and large on/off current ratio of 107. Single-NW-FETs can successfully drive an organic light-emitting diode, revealing the application potential of Zn-doped In2O3 NW-FETs in high-performance displays.

Optimized Ferroelectric PZT Films Deposited on Various Transparent Conducting Oxides for Ferroelectric Transparent Thin-Film Transistors

We have prepared Pb(Zr0.35Ti0.65)O3 (PZT) films on various transparent conductive oxides (TCO), such as Sn-doped In2O3 (ITO), Zn-doped In2O3 (IZO), and Ga-doped ZnO (GZO), in order to investigate the feasibility of transparent thin-film transistors (TTFTs) using a ferroelectric PZT insulator in the bottom-gated TFTs. GZO films deposited at a substrate temperature of 250 ◦C show high crystalline properties while ITO and IZO films have low crystalline and amorphous natures, respectively. Vacuum annealing of the TCO films followed by rapid annealing of the PZT films is performed in order to diminish the interface states between PZT and TCO. Optimized-PZT films with device-worth qualities of P-E hysteresis characteristics and leakage current behaviors are believed to be suitable for ferroelectric gate insulators in transparent TFTs.

Theoretical Study on the Electronic and Electrical Properties of p-Type Transparent Conducting Metal Oxides

Transparent conducting oxides (TCOs) continue to be in high demand because of their immediate applications. In addition to good quality n-type TCOs, there is increasing demand for good p-type TCOs. In the present study, we reported a theoretical study on the electronic and electrical properties for p-type TCO, Zn-doped In2O3 (IZO). The geometries of IZO were optimized using the density functional theory (DFT). Based on these optimized structures, the density of states, frontier molecular orbital contours, and electrical conductivity of IZO were calculated by combining the tight-binding quantum chemical molecular dynamics program, “Colors” and Monte Carlo method. The calculated band gap by “Colors” at G point is 2.87 eV, which is in good agreement with experimental value. In density of states of IZO, a shallow acceptor-type impurity level associate with Zn doping was observed above the top of the valence band. The frontier orbital analysis shows that the acceptor-type impurity level consists of O 2p and Zn 3d. On the other hand, the electrical conductivity and carrier mobility of IZO were evaluated. Comparing the electrical conductivity of IZO with that of its parent material In2O3, it was found that the electrical conductivity increased significantly when Zn-dopant was introduced to In2O3. The higher electrical conductivity of IZO was considered to be attributed to impurity state and therefore the p-type conductivity.

05/00403 Constitutional protection of the environment in a federal country: Canadian experience: Bowal, P. International Journal of Environmental Technology and Management, 2003, 3, (3/4), 295–311

In this communication, indium oxide (In2O3) and Zn-doped In2O3 nanoparticles with different zinc percentage (0–5%) have been prepared by a facile chemical process. A variety of analytical tools such as X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV–Visible, photoluminescence spectroscopy, photocatalytic measurements and impedance spectroscopy were employed to assess the characteristics of prepared nanoparticles (NPs). From XRD analysis it is observed that all samples exhibit pure cubic phase with highly crystalline nature. XPS spectra revealed the composition and chemical state of Zn-doped In2O3 NPs. The estimated optical band gap was found to decrease with increase of Zn concentration. Magnetic hysteresis exhibited that pure and Zn-doped In2O3 NPs possess ferromagnetic behavior at room temperature. Dielectric constant (ε’) as well as dielectric loss (ε’’) decreases exponentially in lower frequency range, but remains almost constant in higher frequency range. Moreover, Zn(5%)-doped In2O3 nanoparticles showed much higher photocatalytic activity as compared with pure In2O3 nanoparticles towards degradation of hazardous methylene blue dye. The results of present study demonstrated that synthesized nanoparticles may be employed efficiently as environmentally convenient photocatalyst for industrial effluent treatment.

The effect of high acceptor dopant concentration of Zn2+ on electrical, optical and structural properties of the In2O3 transparent conducting thin films

In this paper, deposition and electrical, optical and structural characterizations of the In2O3:Zn transparent conducting thin films are investigated. At first, undoped and non-stoichiometric n-In2O3 thin films are deposited using an alcoholic solution by spray pyrolysis technique. Then, in order to prepare Zn-doped In2O3 thin films, certain amounts of zinc chloride are added to the initial solution. Finally, the effects of Zn doping on electrical, optical and structural properties of In2O3 films are studied. The results of XRD analysis, Hall effect experiment and resistivity measurement of films indicate that no phase change in In2O3 lattice occurs in high acceptor doping condition, and for a given acceptor dopant (Zn2+) concentration (∼6wt% in solution), electrical conductivity increases sharply and p-conductivity dominates.