With the great interest in "plasmonics", metallic nano structures have been used for optical applications. The accompanying optical resonance, known as surface plasmon resonance (SPR), has highly motivated researchers because this unique optical phenomenon shows strong interaction with lights within a tiny volume of space. Surface plasmons (SPs) in optically thin metal fi lms contribute to extraordinary optical transmission (EOT) through subwavelength apertures. [ 1 ] Therefore, researchers have suggested plasmonic color fi lters (PCFs) with a selective fi ltering function in subwavelength metallic holes. [2][3][4][5][6] Color fi lters, widely used for the industrial devices such as organic light emitting diodes, liquid crystal displays, and CMOS image sensors, are composed of organic dyes. The fi ltering performance originating from the color sensitivity of the dyes is degraded by heat and ultraviolet radiation due to the low chemical stability of the organic materials. [ 7 ] In addition, the complex structure requires a highly-accurate aligned lithography to spatially separate colors by pixel unit.On the other hand, PCFs have an optically thin metal layer, and their transmittance can be tuned by the geometrical and material conditions: the periodicity, size and shape of holes, the thickness of metal, and the optical constants of the materials. This simple and thin structure is advantageous for assembly into other devices without worry about degradation by heat and light. More recently, PCFs integrated on top of the CMOS image sensor have been reported, [ 6 ] and experimental analysis of spatial cross talk and the effect of defect has been performed in detail. [ 5 ] These results have shown greater possibility for PCFs in industrial applications. However, the fabrication methods used up to now to make plasmonic structures, such as nanoimprinting, [ 8 ] electron beam lithography [2][3][4][5][6] or the focused ion beam method, [ 1,9 ] restrict mass-production of PCFs, leading to problems of low speed, small patterning area, and high cost of equipment.Here we suggest a fabrication fl ow including a laser interference lithography (LIL) step. Contrary to above-mentioned technologies, LIL, with simple maskless equipment, yields perfect ordering patterns, which are, as they must be, spatially coherent over a large area. Although LIL has a limitation in that it can only fabricate simple periodic patterns, it is an attractive additional solution to add to the conventional methods for applications in which periodic patterns are desirable. [ 10 ] In this regard, fabrication of plasmonic color fi lters with LIL enables us to suggest the easiest method to achieve large size PCFs without losing performance aspect. Additionally, a single pixel of the PCFs can be reduced to 1 µm-size; [ 5 ] the interference pattern, with a period of hundreds of nm, is small enough to separate the patterned area into pixel units. Thus, it is possible to effect spatial separation of colors by simple shadow masking and multi exposure. More compli...

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We report on the optical and electrical properties of a novel plasmonic chromatic electrode (PCE). The PCE was composed of a metallic nano-hole array and ITO layer as a dielectric for electrical property. The structure design was optimized to obtain the matched condition between surface plasmon modes at the top and bottom metal-dielectric interfaces for high transmittance. The fabricated PCEs have high transmittance of 25~40% and low resistivity (level of 10−5 Ωcm) compared to conventional electrodes. Due to the multi-functionality and simple structure of PCEs, we predict the PCEs can be applied for advanced industrial use such as, high resolution, flexible, and stretchable devices.

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...

A plasmonic color filter (PCF) containing a metallic nanohole array is described by B.‐K. Ju, K. C. Choi, and co‐workers. This new PCF can be fabricated on an extremely large scale compared to the currently available alternatives, and the process can be adapted to create a flexible product. This is possible by using laser interference lithography based on Lloyd's mirror, as shown in the bottom left of the front cover image. The metal layer is positioned between two dielectric layers (which are different from the substrate), allowing high transmission. The filtering of all primary colors (red, green, and blue) is demonstrated on page 133.