Photo‐Insensitive Amorphous Oxide Thin‐Film Transistor Integrated with a Plasmonic Filter for Transparent Electronics

Abstract

3482www.MaterialsViews.com wileyonlinelibrary.com gate bias stress during most of the driving time and transparent devices are exposed to ambient light unavoidably. The stability resulting from electrical stress under light illumination is important since it can deteriorate the switching performances of a-IGZO-based TFTs. It was found that the positive bias illumination stress is insignifi cant compared to the negative bias illumination stress (NBIS). [ 7 ] NBIS has been explained by photo-induced carriers and the state transition, [7][8][9][10] but the exact mechanism is under debate. In addition, previous reports to improve the stability from NBIS are still insuffi cient from a device viewpoint.Herein we report a more practical use of a-IGZO-based TFTs by adopting plasmonic fi lters (PFs). Metal structures at the submicron scale demonstrate a unique optical response known as a surface plasmon (SP). A metallic fi lm with two dimensional nanohole arrays shows high transmission at the SP resonance frequency and the optical response related to this resonance phenomenon can be easily designed by the material and geometrical factors. This structural coloring technology using thin metal fi lms is superior in fi ltering performance compared to the conventional dye-based color fi lter that experiences degradation by heat and light due to the low chemical stability of the organic-dye material. In addition, thin and quasi-planar structures are advantageous in that they can be easily integrated with other devices. Therefore, PFs have recently been highlighted for use in industrial imaging applications such as CMOS image sensors and displays. [ 11,12 ] With this point of view, we suggest a novel AOS device that has possible applications in transparent electronics, by integrating a-IGZO-TFTs and PFs. A study on NBIS of the suggested a-IGZO-TFTs combined with PFs was performed. Unlike previous work with white or a monochromatic light source, the photosensitivity of a-IGZO-TFTs was investigated with the selectively controlled spectral range of the illumination by the PFs. The suggested TFTs showed extremely improved stability even under a NBIS environment. In addition, compared to the prior AOS TFTs which were equipped with equipped with metal shielding layer to block the light, [ 13 ] our suggestion provides not only the spectral selectivity from the light source but also reduces in the loss of transparency. We expect that the photosensitivity subdivided into spectral ranges will provide a practical guideline for designing structures or a fabrication process of transparent devices and enlarge the usage of AOS TFTs.Optical Characteristics of Plasmonic Filters : One of a prominent optical phenomena of nanohole arrays compared to that of micron scaled structures is extraordinary optical transmission [+] These authors contributed equally to this work. Photo-Insensitive Amorphous Oxide Thin-Film Transistor Integrated with a Plasmonic Filter for Transparent ElectronicsRecently, research interests in amorphous oxide semiconducto...

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