Electrical properties of metal-Langmuir-Blodgett (LB)-metal devices

Abstract

Fundamental electrical properties are investigated for metal-asymmetrical Langmuir-Blodgett (LB) film-metal devices using thermally stimulated currents (TSCs). Alternate-layer LB films of merocyanine (MC) dyes and fatty acids (FAs) are deposited. The orientations of MC molecules are in opposite directions with respect to the substrate. Pyroelectric currents whose directions depend on the orientations of MC molecules are observed between 100 and 300 K without application of bias voltages. In addition, TSC peaks due to dipolar polarization are observed below room temperature. Pyroelectric currents that remarkably increase with temperature above approximately 330 K are observed in the first heating stages for the two types of films. The directions of the currents also depend on the types of LB films, and they are the same for currents below room temperature. The results indicate that positive charges easily transfer from MC head groups to adjacent FA head groups in the heating stages, or that negative charges easily transfer from FA to MC. >