Organic Field Effect Transistors

Field effect transistors

When you look at the field-effect transistors there are three major processes. The first one is the injection of charges into your semi-conductor. In the case of light-emitting diode and photovoltaic cell there are only two electrodes. However, in a field-effect transistor, the charge injection is modulated through a third electrode called a gate. Now all is needed are the electrons and the holes. Let’s suppose you inject electrons. Those electrons must migrate and be collected. The first electrode will be referred to as a gate. Then you have a thin insulator called a dielectric. You have two other electrodes referred to as the source and the drain. Then you have your organic semi-conductor. This is one of the configurations possible. When you are given a voltage difference between the source and drain, the amount of charges that will be injected into your semi-conductor will be modulated by the voltage at the gate. The gate will modulate the injection and produce a switching effect. For a given voltage between the source and drain, the voltage of the gate can either be decreased such that there is a small injection or current or it can be increased to have a very large injection of charges into your semi-conductor and a large current. These are the components that make a transistor, which is also called a three terminal devices because you have 3 electrodes. So once you have an injection of charges into the organic semi-conductor, those charges will travel and be collected at the other electrodes. These are the main steps in an organic semi-conductor; charge injection, charge transport, and charge collection.