Copper Phthalocyanine based Organic Photo Field Effect Transistor as a Sensor for Optical Instrumentation

A thin film of organic p-type semiconducting copper phthalocynanine (CuPc) and a semitransparent Al film were deposited by vacuum evaporation on a glass substrate with Ag film source and drain electrodes. Organic Field Effect Transistor with metal (aluminum)-semiconductor (copper phthalocyanine) Schottky type junction was fabricated. Investigations were made for the effect of modulated LED's irradiation on its characteristics at frequency ranging from 10 Hz-100 kHz. Drain current of organic phototransistor (OPT) was observed to increase quasi-linearly with illumination. Organic field effect transistor was observed to be sensitive at frequency range from 16 Hz to 316 Hz (AC current) and from 16 Hz to 10 kHz (DC current). A block diagram of optical instrumentation with OPT as a sensor is also proposed.