Indium tin oxide

About: Indium tin oxide is a research topic. Over the lifetime, 17857 publications have been published within this topic receiving 402127 citations. The topic is also known as: indium tin oxide.

Optimised pulsed laser deposition of ZnO thin films on transparent conducting substrates

Abstract: The growth of polycrystalline zinc oxide (ZnO) thin films by pulsed laser deposition (PLD) on indium tin oxide (ITO) is reported. For the first time the influence of deposition temperature over an extended range (50–650 °C) is investigated on ITO. We describe the role of temperature on the optical and crystalline properties of the deposited films, of 120–250 nm thickness. Additionally, the effect of the background oxygen pressure is reported. Under all of the deposition conditions highly textured c-axis oriented, transparent (>85%) and low roughness (RMS < 10 nm) ZnO films are formed. Growth temperatures ≥450 °C lead to the highest degree of crystallinity and film quality with measured full width half maximum (FWHM) of X-ray diffraction (XRD) peaks as small as 0.14°2θ. XRD measurements of films grown at <350 °C show a shift in the (002) diffraction peak to lower 2θ values, indicating that the deposited films are oxygen deficient. Increasing the oxygen pressure results in the preparation of stoichiometric films at temperatures as low as 50 °C. We demonstrate that in addition to forming high quality ZnO, the optical and electronic properties of ITO can be preserved—even at high temperature—presenting a methodology for preparing highly crystalline ZnO on ITO over a temperature window significantly larger than that of previous literature reports. Furthermore, the low temperature processing opens up the possibility of deposition on a wide range of substrates, especially those unsuitable for exposure to high temperatures.

Flexible quintuple cation perovskite solar cells with high efficiency

Abstract: Flexible perovskite solar cells (PSCs) present the most promising photovoltaic technologies due to their flexibility, light weight, and low temperature processing. However, their power conversion efficiency (PCE) is still far behind those of rigid PSCs. The enhancement of the PCE of flexible devices remains challenging. Here, two strategies are developed to improve the PCE of flexible PSCs. One strategy is to use quintile monovalent cations to obtain high-quality perovskite films. Rubidium (Rb) and potassium (K) cations are added to a basic perovskite film containing cesium, methylammonium, and formamidinium cations to improve film quality for efficient PSCs. It is revealed that the coexistence of Rb+ and K+ cations can effectively reduce the recombination within PSCs and thus improve the photovoltaic performance. The second strategy is to insert an ultrathin HfO2 layer between indium tin oxide (ITO) and the tin oxide layer by atomic layer deposition at low temperature. The recombination between ITO and perovskite films is found to be effectively suppressed after the introduction of an optimized HfO2 layer. As a result, a record PCE for the PSC devices based on polyethylene naphthalate (PEN)/ITO substrates is obtained as high as 19.11%, which is the highest reported PCE for flexible PSCs to date.

Process for fabricating ferroelectric integrated circuit

Abstract: An oversize ferroelectric capacitor is located against the contact hole to the MOSFET source/drain in a DRAM. A barrier layer made of titanium nitride, titanium tungsten, tantalum, titanium, tungsten, molybdenum, chromium, indium tin oxide, tin dioxide, ruthenium oxide, silicon, silicide, or polycide lies between the ferroelectric layer and the source drain. The barrier layer may act as the bottom electrode of the ferroelectric capacitor, or a separate bottom electrode made of platinum may be used. In another embodiment in which the barrier layer forms the bottom electrode, an oxide layer less than 5 nm thick is located between the barrier layer and the ferroelectric layer and the barrier layer is made of silicon, silicide, or polycide. A thin silicide layer forms and ohmic contact between the barrier layer and the source/drain. The capacitor and the barrier layer are patterned in a single mask step. The ends of the capacitor are stepped or tapered. In another embodiment both the bottom and top electrode may be made of silicon, silicide, polycide or a conductive oxide, such as indium tin oxide, tin dioxide, or ruthenium oxide.

Electrochromic properties of conducting polyanilines

Abstract: A study has been made of the electrochromic behaviour of polyaniline films of potential use in passive display devices, and a preliminary examination of the properties of substituted polyanilines has also been carried out. Films of 'emeraldine-type' conducting polyanilines have been grown electrochemically from aqueous solutions onto glass substrates coated with gold or indium tin oxide. The authors have studied the electrochemistry of their redox reactions in acidic media to examine the kinetics and reversibility. Cyclic voltammetry was used to determine the electrode potentials for growth and redox switching and to obtain information on the electrode kinetics. The effect of electrode potential on the optical absorption spectra was observed, and was found to be consistent with polaron and bipolaron formation. The electrochromic colour contrast and switching times were measured as a function of pH; the requirements were somewhat conflicting, but a satisfactory compromise could be obtained around pH=0. By switching the electrodes over a constant potential step but from a variety of starting potentials, the influence on switching times of the initial oxidation state, and hence of the film conductivity, was investigated. Under suitable circumstances electronic conductivity, ionic transport or interfacial charge-transfer can limit the switching speed, but response times (for 50% transmission change) as short as 15 ms have been obtained without full optimisation. Of the numerous substituted polyanilines tried, only simple alkyl and alkoxy derivatives formed good polymeric films, and only the 2-ethoxy and 2-methoxy polymers gave good electrochromic behaviour. Switching times for these two were very fast, being less than 2.5 ms for both oxidising and reducing potential changes.

Roll-Coated Fabrication of Fullerene-Free Organic Solar Cells with Improved Stability.

Abstract: Large area, fullerene-free organic solar cells with improved stability and efficiency of up to 1% are fabricated by the roll-coating process on indium tin oxide free and flexible substrates, under ambient conditions.