Stefano Lai, Massimo Barbaro, Annalisa Bonfiglio
Sensors and Actuators B: Chemical, Volume 233, pp. 314-319 (2016)
An approach for the fabrication of organic-FET based biosensors with precisely tailored sensing performances is here proposed. A specific device structure, namely Organic Charge-Modulated Field-Effect Transistor (OCMFET), has been analyzed in details and modeled in order to move beyond the pure phenomenological observation of its biochemical sensitivity and precisely determining its sensitivity. Thanks to a complete comprehension of the relationship between sensing ability and device structure, design rules have been derived for tailoring the sensing performances. The layout of the sensor has been optimized according to these design rules. The effectiveness of the approach and of the design is demonstrated by providing a complete electrical characterization of the device in a specific application, namely DNA hybridization detection. Record performances of the OCMFET for direct DNA hybridization detection, both in terms of sensitivity and selectivity, will be reported. As the sensing ability of the device is completely independent of the semiconductor employed for the transistor, the presented results are completely general and may be replicated also for other kinds of semiconductors, thus paving the way to a new generation of biosensing devices based on a variety of semiconducting materials.