Unipolar operating regimes

Figure 17.1 Sketch for the unipolar and ambipolar operation regimes of an organic field-effect transistor.

The differenf operating regimes of an ambipolar tiansisfor are shown in Figure 13.8a. Under cerfain biasing conditions, fhe charmel current in an ambipolar transistor can be approximated by an equivalent circuit comprising of two unipolar, i.e., a p-charmel and an n-channel, transistors connected in parallel as depicted in Figure 13.8b. 

Figure 16.1 Operating regimes of a unipolar FET schematic of a typical FET and graph representation of the linear regime (a), the pinch off point (b), and the saturation regime (c). (Reprinted with permission from Ref [18]).

Smits et al. have derived analytical equations that describe transistor operation under ambipolar and unipolar regimes [110]. The model has been successfully employed for fhe sfudy of ambipolar organic transistors based on a narrow bandgap conjugated molecule, and more recently for the description of light-emitting organic transistors [117]. 

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