14 research outputs found
Publisher's Note: “Low residual doping level in homoepitaxially grown ZnO layers” [Appl. Phys. Lett. 92, 141101 (2008)]
International audienc
Investigation of the milling route for the development of colloidal suspensions to be used as binder in refractory castables
Refractories castables bonded with CAC (calcium aluminate cement) have a limitation when they are used at high temperature in micro-silica containing system and/or in acidic corrosive environments. The CAC binder reacts with the micro-silica and/or acidic components to form liquid/viscous compounds deteriorating the refractory material.Refractory castables bonded with HA (hydratable alumina) perform better in these environments. However, the drying step of such materials needs time and energy for the water evacuation to avoid the lining cracking.The use of CS (colloidal silica) as binder seems to hinder the drawback of CAC and HA binders. However, the presence of free amorphous silica in the castable composition limits their uses in basic environments by forming liquid/viscous phases at high temperature with a reduction of castable refractoriness.In this context, new colloidal bonding systems that could improve the high performances of refractory castables such as boehmite and spinel colloidal suspensions, were developed
Role of vacancy defects in Al doped ZnO thin films for optoelectronic devices
International audienceWe report on the electrical, optical and photoluminescence properties of industry-ready Al doped ZnO thin films grown by physical vapor deposition, and their evolution after annealing under vacuum. Doping ZnO with Al atoms increases the carrier density but also favors the formation of Zn vacancies, thereby inducing a saturation of the conductivity mechanism at high aluminum content. The electrical and optical properties of these thin layered materials are both improved by annealing process which creates oxygen vacancies that releases charge carriers thus improving the conductivity. This study underlines the effect of the formation of extrinsic and intrinsic defects in Al doped ZnO compound during the fabrication process. The quality and the optoelectronic response of the produced films are increased (up to 1.52 m Omega.cm and 3.73 eV) and consistent with the industrial device requirements
Study of Fluorine-doped SnO2 thin films with tunable Haze Factor
International audienc
Study of Fluorine-doped SnO2 thin films with tunable Haze Factor
International audienc
Chemically assisted vapour transport for bulk ZnO crystal growth
International audienceA chemically assisted vapour phase transport (CVT) method is proposed for the growth of bulk ZnO crystals. Thermodynamic computations have confirmed the possibility of using CO as a sublimation activator for enhancing the sublimation rate of the feed material in a large range of pressures (10(-3) to 1 atm) and temperatures (800-1200 degrees C). Growth runs in a specific and patented design yielded single ZnO crystals up to 46 mm in diameter and 8 mm in thickness, with growth rates up to 400 mu m/h. These values are compatible with an industrial production rate. N type ZnO crystals (mu = 182 cm(2)/(V s) and n=7 10(15) cm(-3)) obtained by this CVT method (Chemical Vapour Transport) present a high level of purity (10-30 times better than hydrothermal ZnO crystals), which may be an advantage for obtaining p-type doped layers ([Li] and [Al] < 10(+15) cm(-3)). Structural (HR-XRD), defect density (EPD), electrical (Hall measurements) and optical (photoluminescence) properties are presented