Electrical characterisation of stearic acid/eicosylamine alternate layer Langmuir-Blodgett films incorporating US nanoparticles

Electrical properties of stearic acid/cicosylamine alternate layer Langmuir-Blodgett (LB) film structure incorporating cadmium sulphide (CdS) nanoparticles are studied in the temperature range 300-400 K. The room temperature ohmic conductivity is found to be 3.87 x 10-(13) Sm-1 for the as deposited LB film and 7.75 x 10(-12) Sm-1 for the LB film containing US nanoparticles. At a relatively high field the electrode-limited Schottky effect is found to be responsible for conduction mechanism. The potential barrier height is calculated at several temperatures for the metal/LB film/metal system and the average temperature coefficient is found to be 0.0048 eV K-1 for the untreated LB film and 0.005 eV K-1 for the CdS containing LB film. Activation energies are found to be 0.46 eV and 0.19 eV for the untreated LB film and the LB film with CdS natioparticles, respectively. The alternating current conductance for both samples shows typical power law dependence with a value of similar to 0.9 for the frequency dependence exponent. (c) 2006 Elsevier B.V. All rights reserved.