High-Performance Solution-Processed Amorphous Zinc−Indium−Tin Oxide Thin-Film Transistors

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• 作者：Myung-Gil Kim ; Hyun Sung Kim ; Young-Geun Ha ; Jiaqing He ; Mercouri G. Kanatzidis ; Antonio Facchetti ; Tobin J. Marks
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：August 4, 2010
• 年：2010
• 卷：132
• 期：30
• 页码：10352-10364
• 全文大小：760K
• 年卷期：v.132,no.30(August 4, 2010)
• ISSN：1520-5126

文摘

Films of the high-performance solution-processed amorphous oxide semiconductor a-ZnIn₄Sn₄O₁₅, grown from 2-methoxyethanol/ethanolamine solutions, were used to fabricate thin-film transistors (TFTs) in combination with an organic self-assembled nanodielectric as the gate insulator. This structurally dense-packed semiconductor composition with minimal Zn²⁺ incorporation strongly suppresses transistor off-currents without significant mobility degradation, and affords field-effect electron mobilities of 90 cm² V⁻¹ s⁻¹ (104 cm² V⁻¹ s⁻¹ maximum obtained for patterned ZITO films), with I_on/I_off ratio 10⁵, a subthreshhold swing of 0.2 V/dec, and operating voltage <2 V for patterned devices with W/L = 50. The microstructural and electronic properties of ZITO semiconductor film compositions in the range Zn_9−2xIn_xSn_xO_9+1.5x (x = 1−4) and ZnIn_8−xSn_xO_13+0.5x (x = 1−7) were systematically investigated to elucidate those factors which yield optimum mobility, I_on/I_off, and threshold voltage parameters. It is shown that structural relaxation and densification by In³⁺ and Sn⁴⁺ mixing is effective in reducing carrier trap sites and in creating carrier-generating oxygen vacancies. In contrast to the above results for TFTs fabricated with the organic self-assembled nanodielectric, ZnIn₄Sn₄O₁₅ TFTs fabricated with SiO₂ gate insulators exhibit electron mobilities of only 11 cm² V⁻¹ s⁻¹ with I_on/I_off ratios 10⁵, and a subthreshhold swing of 9.5 V/dec.