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Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors

Abstract

Transparent electronic devices formed on flexible substrates are expected to meet emerging technological demands where silicon-based electronics cannot provide a solution. Examples of active flexible applications include paper displays and wearable computers1. So far, mainly flexible devices based on hydrogenated amorphous silicon (a-Si:H)2,3,4,5 and organic semiconductors2,6,7,8,9,10 have been investigated. However, the performance of these devices has been insufficient for use as transistors in practical computers and current-driven organic light-emitting diode displays. Fabricating high-performance devices is challenging, owing to a trade-off between processing temperature and device performance. Here, we propose to solve this problem by using a novel semiconducting material—namely, a transparent amorphous oxide semiconductor from the In-Ga-Zn-O system (a-IGZO)—for the active channel in transparent thin-film transistors (TTFTs). The a-IGZO is deposited on polyethylene terephthalate at room temperature and exhibits Hall effect mobilities exceeding 10 cm2 V-1 s-1, which is an order of magnitude larger than for hydrogenated amorphous silicon. TTFTs fabricated on polyethylene terephthalate sheets exhibit saturation mobilities of 6–9 cm2 V-1 s-1, and device characteristics are stable during repetitive bending of the TTFT sheet.

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Figure 1: Schematic orbital drawings for the carrier transport paths (that is, conduction band bottoms) in crystalline and amorphous semiconductors.
Figure 2: Amorphous IGZO films.
Figure 3: Flexible TTFTs.
Figure 4: Typical TTFT characteristics before and after bending.

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Correspondence to Hideo Hosono.

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Nomura, K., Ohta, H., Takagi, A. et al. Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors. Nature 432, 488–492 (2004). https://doi.org/10.1038/nature03090

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