From Ambipolarity to Multifunctionality: Novel Library of Polymorphic Gates Using Double-Gate FETs

Ambipolarity, a unique feature typically found in some post-silicon devices, e.g. CNT or organic FETs, is still treated today just as something rather peculiar. But in reality, it does not hinder such devices from utilization when it comes to the implementation of logic. From other point of view, this feature could be perceived as an opportunity to implement the logic in more refined and efficient way. The practical impact of ambipolarity results in devices which becomes more versatile than conventional FET element. 

In this paper, a set of multifunctional logic gates based on ambipolar FETs is presented. The multifunctionality of these gates means that each gate could exhibit one of two defined functions in a given moment. The selection of their function depends on circumstances under which the circuit is operated. The proposed set of gates could be employed in multifunctional circuits using techniques and procedures established for polymorphic electronics. This field of study, yet proposed nearly 20 years ago, now offers synthesis methods and application approaches to obtain an efficient implementation of more than one function in one logic circuit.