| 초록 |
We demonstrated visible-light phototransistors based on a ZnO/QDs/TiO2 heterostructure to improve the photodetection characteristics. The QDs enabled the absorption of visible light, generated photoexcited charge carriers at the conduction band of QDs, and then these carriers could be efficiently injected into the conduction bands of ZnO and TiO2 with the low injection barrier, which could generate a large photocurrent. The phototransistors with a ZnO/QDs/TiO2 exhibited the photosensitivity of 4.2×106, photoresponsivity of 6.84×10−2 A W-1, and a high transition rate of 0.728 ns-1, which means high value enough to reduce PPC effect. ALD-TiO2 layer could enhance electrical characteristics and device stability of bilayer ZnO/QDs phototransistors with protecting the surface of the bilayer. These results offer a useful way to apply the enhanced visible light phototransistors with a ZnO/QDs/TiO2 heterostructure. |
