The physical properties of SnS films grown on lattice-matched and amorphous substrates

The development of high-quality tin monosulphide (SnS) layers is one of the crucial tasks in the fabrication of efficient SnS-based optoelectronic devices. Reduction of strain between film and the substrate by using an appropriate lattice-matched (LM) substrate is a new attempt for the growth of high-quality layers. In this view, the SnS films were deposited on LM Al substrate using the thermal evaporation technique with a low rate of evaporation. The as-grown SnS films were characterized using appropriate techniques and the obtained results are discussed by comparing them with the properties of SnS films grown on amorphous substrate under the same conditions. From structural analysis of the films, it is noticed that the SnS films deposited on amorphous substrate have crystallites that were oriented along different directions. However, the SnS crystallites grown on Al substrate exhibited epitaxial growth along the 101] direction. Photoluminescence (PL) and Raman studies reveal that the films grown on Al substrate have better optical properties than those of the films grown on amorphous substrates. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinetics of copolyurethane network formation

Cure kinetics for the formation of copolyurethane networks of various compositions based on hydroxy-terminated polybutadiene(HTPB), poly(12-hydroxy stearic acid-co-TMP) ester polyol(PEP), and different isocyanates has been studied through viscosity build up during the cure reaction. The viscosity (N)-time (t) plots conform to the equation N = ae(bt), where a and b are empirical constants, dependent on the composition and the nature of the polyols and the isocyanates. The rate constants (b) for viscosity build up, evaluated from the slopes of dN/dt versus N plots at different temperatures, were found to vary significantly from 0.0073 to 0.25 min(-1); and the activation energies for gelation were found to be in the range 20 to 40 kJ mol(-1). The results have been interpreted in terms of the dependence of the rate constants on structural characteristics of the prepolymers. (C) 1997 John Wiley & Sons, Inc.

Zinc Oxide Modified Au Electrode as Sensor for an Efficient Detection of Hydrazine

ZnO nanoparticles (ZnO NPs) prepared by microwave heating technique are used to modify a gold electrode (ZnO/Au) for the hydrazine detection study. The synthesized product is well characterized by various techniques. Detailed electrochemical investigation of the oxidation of hydrazine on the ZnO/Au electrode in 0.02 M phosphate buffer solution (PBS) of pH 7.4 was carried out. A very low detection limit of 66 nM (S/N=4) and a wide linearity in current for a concentration range from 66.0X10-3 to 415 mu M was achieved by amperometry. The electrode was found to be stable for over a month when preserved in PBS.