High-Performance Visible-Blind Ultraviolet Photodetector Based on IGZO TFT Coupled with p–n Heterojunction

A visible-blind ultraviolet (UV) photodetector was designed based on a three-terminal electronic device of thin-film transistor (TFT) coupled with two-terminal p–n junction optoelectronic device, in hope of combining the beauties of both of the devices together. Upon the uncovered back-channel surface of amorphous indium–gallium–zinc-oxide (IGZO) TFT, we fabricated PEDOT:PSS/SnO x /IGZO heterojunction structure, through which the formation of a p–n junction and directional carrier transfer of photogenerated carriers were experimentally validated. As expected, the photoresponse characteristics of the newly designed photodetector, with a photoresponsivity of 984 A/W at a wavelength of 320 nm, a UV–visible rejection ratio up to 3.5 × 107, and a specific detectivity up to 3.3 × 1014 Jones, are not only competitive compared to the previous reports but also better than those of the pristine IGZO phototransistor. The hybrid photodetector could be operated in the off-current region with low supply voltages (