I- Introduction

II- Ofets Fabrication Process

III- DC Characterization

IV- AC Characterization

V- Conclusions

References

Abstract

Thanks to recent progress in terms of materials properties, polymer field-effect transistors (FETs) operating in the MHz range can be achieved. However, further development toward challenging frequency ranges, for a field accustomed to slow electronic devices, has to be addressed with suitable device design and measurements methodologies. In this letter, we report n-type FETs based on a solution-processed polymer semiconductor where the critical features have been realized by a large-area compatible direct-writing technique, allowing to obtain a maximum frequency of transition of 19 MHz, as measured by means of ScatteringParameters (S-Parameters).This is the first report of solution-processed organic FETs characterized with SParameters.

INTRODUCTION

ORGANIC electronics underwent an impressive development and thanks to its peculiar properties, e.g. high degree of tunability of electronic properties and thin molecular films deposition with scalable processes at low temperature on a wide variety of substrates, represent one of the most promising candidates in the path to ubiquitous, flexible and lightweight low-cost electronics. To date, organic light emitting diodes (OLEDs) [1] have reached commercial maturity, and significant progress has been achieved for organic solar cells [2], photodetectors [3], biosensors [4] and circuits based on organic transistors [5]. In the case of field effect transistors (FETs), the use of polymer semiconductors has the advantage of achieving superior mechanical properties and easily enabling large-area fabrication techniques, such as printing. Excellent DC performances have been recently achieved owing to an improvement in the understanding of device physics [6], and steady increase in charge carrier mobility [7] and charge carrier injection [8]. Yet, progresses in DC performances are not usually matched by corresponding improvements in AC properties, since typical FET structures devised to test new polymer semiconductors are not optimized for frequency operation. It is instead highly demanded to enhance polymer FET maximum operational frequency, as this would enable a much broader application of this technology. For example, higher operational frequencies are crucial in drivers for high resolution flexible displays [9], radio frequency identification (RFID) systems for smart items identification [10] or wireless communication [11].