Color Thin-Film Transistors Employing Periodic Nanohole Structures

A thin-film transistor (TFT) with a color filter function achieved by designing periodic nanohole arrays in the metal electrodes was studied. Since this metal electrode is not opaque but transparent to a specific color of light, the TFT structure has unique optical characteristics that can be used in broader applications. An aluminum metal electrode with nanohole arrays permitted specific color transmission by the surface plasmon phenomenon, depending on the spacing between holes, from blue to red. Although the gate electrode of the TFT had a nanohole structure, its electrical characteristics and the electrical field distribution in the gate oxide were almost similar to that of a common metal electrode structure. The TFTs with the nanohole arrays showed similar electrical performances to general TFTs without the nanohole structure. The values of 0.7 V/decade subthreshold swing and >107 ION/IOFF ratio were measured. The TFTs with the nanohole arrays on the metal layer were transparent in a specific color range and still kept its original electrical functionality. Therefore, the color TFT structure can be a good solution for various applications such as a solution for the low aperture issue in organic light-emitting diode (OLED) displays or low reliability in a flexible transparent display while offering a simpler fabrication process.