It has been widely known that the wireless communication industry has been experiencing rapid development since its first commercial product became available in market (in 1973 provided by Motorola). However, TFT-based wireless communication systems are new and developments have been somewhat slow since the performance of the TFT, in particular its cut-off frequency (fT), is much lower compared with that of the MOSFET. The primary use of the TFT is still limited to liquid-crystal displays (LCD). Progress in material science continues to push the cut-off frequencies to higher values, creating a great opportunity to extend the TFT applications to wireless communications using flexible electronics.
Interactive Display Systems
Besides its obvious application in active matrix displays, the oxide TFT technology can also be used as photosensors for visible light applications because of the presence of oxygen vacancies in the sub-gap states. For photosensor applications, we need to overcome the slow recovery due to persistent photoconductivity. But techniques for adjusting the virgin VT in a dual gate photo-TFT through independent control based on a positive gate voltage control scheme. In the example shown here, the TFT considered is a photosensor for imaging applications, in which a transparent conducting In-rich IZO layer is employed as the top gate to yield minimum degradation in device photosensitivity. The huge responsivity of the photo TFT observed was attributed to high photo–conductive gain because of efficient e-h separation by virtue of band structure. This retards the recombination rate, thus allowing for a longer carrier life-time.