Structural and thermal studies of silver nanoparticles and electrical transport study of their thin films

This work reports the preparation and characterization of silver nanoparticles synthesized through wet chemical solution method and of silver films deposited by dip-coating method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and energy dispersive spectroscopy (EDX) have been used to characterize the prepared silver nanoparticles and thin film. The morphology and crystal structure of silver nanoparticles have been determined by FESEM, HRTEM, and FETEM. The average grain size of silver nanoparticles is found to be 17.5 nm. The peaks in XRD pattern are in good agreement with that of face-centered-cubic form of metallic silver. TGA/DTA results confirmed the weight loss and the exothermic reaction due to desorption of chemisorbed water. The temperature dependence of resistivity of silver thin film, determined in the temperature range of 100-300 K, exhibit semiconducting behavior of the sample. The sample shows the activated variable range hopping in the localized states near the Fermi level

Effect of selenium incorporation at precursor stage on growth and properties of Cu2ZnSnSe4 thin films

In the present work, the effect of the selenium incorporation in between the Sn-ZnSe-Cu precursor layers on growth of Cu2ZnSnSe4 thin films by employing selenization is reported. Multiple stacks of precursors (Sn/Se/ZnSe/Se/Cu/Se) were sequentially evaporated in high vacuum onto soda lime glass substrates held at 100 degrees C and their subsequent selenization at 350 degrees C using a tubular furnace led to the complete crystallization into single phase Cu2ZnSnSe4 films. X-ray diffraction pattern of stacked layers selenized at 350 degrees C revealed the formation of kesterite-type Cu2ZnSnSe4 films with a preferred orientation along (112) plane. Raman analysis using multi wavelength excitation confirms the growth of single phase CZTSe films. Secondary ion mass spectroscopy (SIMS) depth profiles illustrated fairly uniform distribution of constituent elements. Optical absorption studies of the films showed an optical band gap of 0.97 eV with high absorption coefficient (> 10(4)cm(-1)). The electrical properties of the films exhibited p-type conductivity with resistivity of 4.18 Omega cm, mobility of 11.3 cm(2)(Vs)(-1) and carrier concentration of 1.32 x 10(17) cm(-3). Our approach and results would open a new way for the synthesis of Cu2ZnSnSe4 directly on plastic substrates. (c) 2017 Elsevier Ltd. All rights reserved