| 초록 |
Indium-gallium-zinc-oxide (IGZO) is one of good candidates as a channel material for thin-film transistors (TFTs) due to high electron mobility and device stability, enabling a variety of potential applications such as displays and sensors.[1,2] IGZO also has a wide-band gap of ~3.5 eV corresponding to the UV band and such optical properties indicate the possibility as UV photodetectors. In particular, phototransistors based on thin-film transistors are quite promising due to low dark current and high photocurrent gain. However, the persistent photoconductivity (PPC) in IGZO, which is an inherent drawback resulting in the inhibition of photocurrent decay, hampers repeatable UV sensing, limiting the real-time sensing ability of IGZO-based phototransistors.[3] In this presentation, we employ a biomaterial on the surface of a IGZO TFT to modify the surface properties of the device. The optoelectronic properties including rise and decay behaviors of photocurrent were characterized and qualitatively explained based on the surface potential results and the energy band diagram for the devices with and without biomaterials. We conclude that the employed biomaterial plays an important role in the enhanced photoresponse characteristics of IGZO photo-TFTs, inducing the surface potential variation, which enables to alleviate PPC in the device leading to the recombination of photo-generated electrons.
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