Gate bias

Although the relationship between the channel charge and gate bias can be compHcated, it can be simply approximated as a capacitor stmcture. In this simplification the foUowiag equation holds, where q is the electron charge,... 

At the same time, we determined the trap-free mobility, that is, the mobility corresponding to a high gate bias, at which all traps are filled. Interestingly, as shown in Table 14-4, we found a similar trap-free mobility in 6T and DH6T, de-... 

In a MESFET, a Schottky gate contact is used to modulate the source-drain current. As shown in Figure 14-6b, in an //-channel MESFET, two n+ source and drain regions are connected to an //-type channel. The width of the depletion layer, and hence that of the channel, is modulated by the voltage applied to the Schottky gate. In a normally off device (Fig. 14-9 a), the channel is totally depleted at zero gate bias, whereas it is only partially depleted in a normally on device (Fig. 14-9 b). 

This section is divided in two parts. In the first one, we review the studies on the transport mechanism in materials used in OFETs, whereby temperature-depen-dent measurements are a very powerful tool. The study of the gate bias dependence has also been used by researchers. In the second part, we present the few analytical models of the organic FETs that have been developed until now. 

Ge-ion implant in Si narrows the bandgap in the source region, which enhances hole flow in that region. The procedure improves performance by lowering the drain breakdown voltage. In a low-gate bias, this voltage improvement -1 eV has been achieved by an ion implantation method. 

There are three basic types of semiconductor materials depending on their ability to conduct hole (p-type), electrons (n-type), or both (ambipo-lar) under different gate bias conditions. In semiconductor materials, reduction of the bandgap (Eg) will enhance the thermal population of the conduction band and thus increase the number of intrinsic charge carriers. The decrease of Eg can led to true organic metals showing intrinsic electrical conductivity. 

Contact resistance is gate-bias-dependent it decreases substantially when gate... 

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