Structural characterization and electrical properties of nanostructured 4-tricyanovinyl-N,N-diethylaniline thin films

X-ray diffraction (XRD) patterns indicated that the powder of 4-tricyanovinyl-N,Ndiethylaniline (TCVA) has a polycrystalline structure with triclinic crystal system. The scanning electron microscope of the as deposited TCVA thin film shows a nanocrystalline structure with crystallite size of 45-75 nm. The crystallite size increases by increasing film thickness and annealing temperatures. The dark electrical resistivity decreases with increasing film thickness. Such variations are a consequence of crystallite size effect on the electrical resistivity of the films. The conductivity of the films measured in air is high in comparison to those measured under vacuum by one order. The removal of the hydroxyl group states by evacuation decreased the electrical conductivity of TCVA films. The temperature dependence of the electrical conductivity of TCVA films shows that the conduction is through a thermally activated process having two conduction mechanisms. The average values of activation energies are 0.28 and 0.74 eV for extrinsic and intrinsic conduction mechanisms, respectively. H-O group adsorption is responsible for the extrinsic conduction in TCVA films.