ORGANIC PHOTOCONDUCTOR TTF-TCNQ (TETRATHIAFULVALENETETRACYANOQUINODIMETHANE): A POTENTIAL ROOM TEMPERATURE INFRARED DETECTOR AT 10 ?m H. R. Mohajeri Moghaddam* and N. Peyghambarian

Abstract

The absorption properties of charge transfer organic semiconductor TTF-TCNQ (tetrathiafulvalene-tetracyanoquhodimete ) filmsdeposited on KBr singlecrystal, quartz and glass substrates in far infrared have been investigated. An absorption edge at ?10 ??m was observed. Photoconductivity, photoconduction efficiency and gain and photocarrier's lifetime have been measured. The results show an electric field dependent photoconductivity.At an applied voltage of 14 V the photoconductivity reaches 1.2 (ohm-cm) which is almost the same as that of its DC dark conductivity, i.e. 1.8 (ohm-cm) . Low temperature results show that the performance of the detector does not improve, but the field dependency, which was shown at room temperature, did not occur at low temperatures. The laser power dependency of the photocarriers showed that a single photon absorption process is involved. Slight deviation from linear dependency could be attributed to trapping in the band gap. It was concluded that the material may potentially be used as a CO laser detector