Study On The Circuit Model Of Single Layer Photoresponsive Organic Field-effect Transistors

Photoresponsive organic field-effect transistors(Phot OFETs)is an important kind of organic field-effect transistor(OFET).The optical signal can be converted into electrical signal by phot OFETs conveniently.Therefore it is widely used in the fields of photosensitive sensor and photosensitive imaging.At present,the research on the circuit model of the phot OFETs is not sufficient.However the circuit model of phot OFETs which can be applied to SPICE simulation is urgently needed by whether device or integrated circuit.Accordingly,the study on the circuit model of single layer phot OFETs was presented in this paper,including the fabrication of the single layer Ti OPc(phthalocyanine titanium oxide)phot OFET,the device modelling and SPICE simulation.The main work and conclusions of this paper is shown as follows: 1.The bottom-gate top-contact geometry of single layer Ti OPc Phot OFET was fabricated and tested under the wavelength of 808 nm and 650 nm.The electrical characteristic was analyzed.2.Based on the conventional a-Si:H MOSFET model and OFET model,the phot OFET circuit model was presented in this paper.The methods of parameter extraction was improved and modified.Both Cu Pc Phot OFETs and Ti OPc Phot OFET were used to prove the validity of the modified model.3.An equivalent SPICE model of single phot OFET was obtained,which has been applied to the inverter,common gate amplifier,common source amplifier and common drain amplifier that composed by single-layer Ti OPc phot OFET.Compared to the traditional IC,the simulation results show the different characteristics.Based on single-layer Ti OPc phot OFET,the inverter under low voltage has no inverting function in dark,while it can realize the function of the inverter under illuminance.The common gate and common source amplifiers appear the magnificent change in the dark and illuminance,which shows the illuminance modulation effect.For the common drain amplifier,the voltage amplifier factor is not change in different illuminance conditions.