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Effects of Oxygen Content on Operational Characteristics and Stability of High-Mobility IGTO Thin-Film Transistors during Channel Layer Deposition. COATINGS 2021. [DOI: 10.3390/coatings11060698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, we investigated the effects of oxygen content on the transfer characteristics and stability of high-mobility indium-gallium-tin oxide (IGTO) thin-film transistors (TFTs) during channel layer deposition. The IGTO thin films were deposited through direct current sputtering at different ambient oxygen percentages of 10%, 20%, 30%, 40%, and 50%. The experimental results indicate that the drain currents were hardly modulated by the gate-to-source voltage in the IGTO TFT prepared at 10% ambient oxygen. However, as the oxygen content increased from 20% to 50%, the transfer curves shifted to the positive direction with a decrease in field-effect mobility (μFE). The IGTO TFTs exhibited deteriorated positive bias stress (PBS) stability as the oxygen content increased. However, the stabilities of the IGTO TFTs under negative bias illumination stress (NBIS) improved with an increase in the ambient oxygen percentage during the channel layer deposition. Furthermore, to understand the mechanism of the observed phenomena, we performed X-ray photoelectron spectroscopy (XPS) analysis of the IGTO thin films prepared at different oxygen percentages. The XPS results demonstrate that the deteriorated PBS stability and enhanced NBIS stability of the IGTO TFTs prepared at higher oxygen percentages were mainly ascribed to the larger amount of oxygen interstitials resulting from the excess oxygen and the smaller number of oxygen vacancies within the IGTO, respectively. The obtained results suggest that the oxygen percentages of 30% in the sputtering ambient is the most suitable oxygen percentage for optimizing the electrical properties (μFE = 24.2 cm2/V·s, subthreshold swing = 0.43 V/dec, and threshold voltage = −2.2 V) and adequate PBS and NBIS stabilities of IGTO TFTs.
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Kim BS, Won S, Seo J, Jeong SK, Kim C, Kim KS, Kim SH, Cho SM, Kim JH. Embedded Reverse-Offset Printing of Silver Nanowires and Its Application to Double-Stacked Transparent Electrodes with Microscale Patterns. ACS APPLIED MATERIALS & INTERFACES 2021; 13:26601-26609. [PMID: 34033467 DOI: 10.1021/acsami.1c04858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We propose an embedded reverse-offset printing (EROP) method, which generates silver nanowire (AgNW) transparent electrodes for display applications. The proposed EROP method can solve the two critical issues of microscale pattern formation and surface planarization. The AgNW electrode had a transmittance of 82% at 550 nm, a sheet resistance of 12.2 Ω/sq, and a 3.27 nm smooth surface. We realized the roll-based pattern formation of AgNW on a plastic substrate as small as 10 μm with negligible step differences to facilitate the proposed method. The proposed EROP method also produced a double-stacked AgNW electrode, enabling the simultaneous operation of separately micropatterned devices. To verify the usefulness of EROP, we fabricated an organic light-emitting diode (OLED) device to demonstrate leakage current reduction and efficiency improvement compared with a conventional indium tin oxide (ITO)-based OLED device. The EROP-based OLED showed 38 and 25% higher current efficiencies than an insulator-patterned AgNW OLED and a conventional ITO-based OLED, respectively.
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Affiliation(s)
- Bong Sung Kim
- Nano-Convergence Mechanical Systems Research Division, Korea Institute of Machinery & Materials, Daejeon 34103, Republic of Korea
| | - Sejeong Won
- Center for Advanced Meta-Materials (CAMM), Daejeon 34103, Republic of Korea
| | - Jungkook Seo
- Novel Material Research Laboratory, School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Sang Kyu Jeong
- Novel Material Research Laboratory, School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Chan Kim
- Nano-Convergence Mechanical Systems Research Division, Korea Institute of Machinery & Materials, Daejeon 34103, Republic of Korea
- Nanomechatronics, University of Science & Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea
| | - Kwang-Seop Kim
- Nano-Convergence Mechanical Systems Research Division, Korea Institute of Machinery & Materials, Daejeon 34103, Republic of Korea
- Nanomechatronics, University of Science & Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea
| | - Sun Ho Kim
- Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Sung Min Cho
- Novel Material Research Laboratory, School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Jae-Hyun Kim
- Nano-Convergence Mechanical Systems Research Division, Korea Institute of Machinery & Materials, Daejeon 34103, Republic of Korea
- Nanomechatronics, University of Science & Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea
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Lu K, Yao R, Xu W, Ning H, Zhang X, Zhang G, Li Y, Zhong J, Yang Y, Peng J. Alloy-Electrode-Assisted High-Performance Enhancement-Type Neodymium-Doped Indium-Zinc-Oxide Thin-Film Transistors on Polyimide Flexible Substrate. RESEARCH 2021; 2021:5758435. [PMID: 33842892 PMCID: PMC8010622 DOI: 10.34133/2021/5758435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/01/2021] [Indexed: 11/17/2022]
Abstract
Flexible thin-film transistors with high current-driven capability are of great significance for the next-generation new display technology. The effect of a Cu-Cr-Zr (CCZ) copper alloy source/drain (S/D) electrode on flexible amorphous neodymium-doped indium-zinc-oxide thin-film transistors (NdIZO-TFTs) was investigated. Compared with pure copper (Cu) and aluminum (Al) S/D electrodes, the CCZ S/D electrode changes the TFT working mode from depletion mode to enhancement mode, which is ascribed to the alloy-assisted interface layer besides work function matching. X-ray photoelectron spectroscopy (XPS) depth profile analysis was conducted to examine the chemical states of the contact interface, and the result suggested that chromium (Cr) oxide and zirconium (Zr) oxide aggregate at the interface between the S/D electrode and the active layer, acting as a potential barrier against residual free electron carriers. The optimal NdIZO-TFT exhibited a desired performance with a saturation mobility (μsat) of 40.3 cm2·V−1·s−1, an Ion/Ioff ratio of 1.24 × 108, a subthreshold swing (SS) value of 0.12 V·decade−1, and a threshold voltage (Vth) of 0.83 V. This work is anticipated to provide a novel approach to the realization of high-performance flexible NdIZO-TFTs working in enhancement mode.
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Affiliation(s)
- Kuankuan Lu
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Rihui Yao
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Wei Xu
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Honglong Ning
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Xu Zhang
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Guanguang Zhang
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Yilin Li
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Jinyao Zhong
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Yuexin Yang
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Junbiao Peng
- State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China
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