All-Optical-Input Transistors With Light-Controlled Enhancement And Fast Stabilization Of Hot-Electron Photocurrent

An optical-controlled photocurrent transistor of Au/TiO2 was prepared by a sol-gel method, and the photoelectric properties were studied. Different from traditional phototransistors that apply electricity to control photocurrent, in this work, an ultraviolet light (gate light) is introduced to regulate the hot-electron photocurrent excited by infrared light (source light). It is found that the hot-electron photocurrent excited by source light in the Au electrode can be controlled by gate light. The gate light can result in the generation of the photogenerated electron-hole pairs in TiO2, leading to the photodesorption of oxygen absorbed on the surface of TiO2, and then the Schottky barrier between Au and TiO2 is reduced. The reduction of the Schottky barrier and the trap-filling effect give rise to the enhancement of hot-electron photocurrent by tens of time. With the power of the gate light increasing, the enhanced photocurrent reaches a stable state quickly. More importantly, this Au/TiO2 transistor is expected to be used for signal enhancement, modulation, and switching.