Electrical Properties of Au/Polyimide/Squarylium-Arachidic Acid Junctions Fabricated by the Langmuir-Blodgett Technique

Abstract

We fabricated metal-insulator-semiconductor (MIS) junctions having the structure of a Au/polyimide (PI)/squarylium dyearachidic acid (SQ-C20) mixed system by the Langmuir-Blodgett (LB) technique, and then examined the electrical properties of the junctions. It was found that a PI LB film becomes a good electrical insulator even when the number of deposited layers is 5. From the capacitance-voltage (C-V) measurement, it was found that a (SQ-C20) multilayered film is depleted at the interface between the PI layer and the (SQ-C20) layer even when biasing voltage was zero millivolt because positive excess charges are displaced from the gate-Au electrode to the PI layer as deposited. The polyimide layer incorporated in the junctions makes a significant contribution to the electrical conduction, and asymmetric current-voltage (I-V) characteristics were obtained for the junctions.