Article
Chemistry, Multidisciplinary
Yue Zhou, Dao Wang, Yushan Li, Lixin Jing, Shuangjie Li, Xiaodan Chen, Beijing Zhang, Wentao Shuai, Ruiqiang Tao, Xubing Lu, Junming Liu
Summary: The pulsed laser deposition (PLD) technique shows potential in developing a-IGZO TFTs for flexible applications due to its low processing temperature and easy operation in an oxygen atmosphere. This study systematically investigates the effects of oxygen pressure and post-annealing processes on the performance of a-IGZO TFTs prepared by PLD. The results demonstrate that high-quality devices can be obtained at specific oxygen pressure, and the presence of oxygen vacancies significantly affects the device performance.
Article
Materials Science, Multidisciplinary
Ruozheng Wang, Qiang Wei, Jie Li, Jiao Fu, Yiwei Liu, Tianfei Zhu, Cui Yu, Gang Niu, Shengli Wu, Hongxing Wang
Summary: In this study, bottom gate a-IGZO TFTs based on HfO2 stacked dielectrics with decent electrical characteristics and bias stability were fabricated. Through surface modification of the SiNx film, a more uniform layer was achieved, leading to improved quality of SHS stacked dielectrics. Zr-doped HfO2 was found to improve electrical characteristics and decrease bulk defect states, resulting in enhanced stability of the device.
Article
Engineering, Electrical & Electronic
Junhong Park, Chan Young Kim, Myeong Ji Kim, Seungyeop Choi, Yong Ha Hwang, Kyung Cheol Choi
Summary: To implement wearable textile displays, it is important to maintain the unique properties of textiles while achieving high resolution and high frame-rate displays. This study optimized and applied transparent and flexible electrodes, as well as used vacuum deposition and oxide-based materials for thin film transistors (TFTs). Textile-based TFTs showed good electrical performance, transparency, and flexibility, even in low temperature processes. Furthermore, they demonstrated stable driving capabilities for organic light-emitting diodes on textile.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Junhong Park, Chan Young Kim, Myeong Ji Kim, Seungyeop Choi, Yong Ha Hwang, Kyung Cheol Choi
Summary: To implement wearable textile displays, it is important to maintain the unique properties of textiles, such as physical and chemical properties, aesthetics, and flexibility, while achieving high resolution and high frame-rate displays. Thin film transistors (TFTs) with excellent electrical properties were used for this purpose, with all layers formed by vacuum deposition and oxide-based transparent materials. A transparent and flexible electrode with an optimized structure was applied to the source/drain and gate. The textile-based TFTs showed good electrical performance, transparency, and flexibility, even after bending tests and low temperature processing.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Physics, Multidisciplinary
Wen Xiong, Jing-Yong Huo, Xiao-Han Wu, Wen-Jun Liu, David Wei Zhang, Shi-Jin Ding
Summary: This study investigates amorphous In-Ga-Zn-O (a-IGZO) thin-film transistor (TFT) memories with novel p-SnO/n-SnO2 heterojunction charge trapping stacks (CTSs) under a maximum fabrication temperature of 280 degrees C. Compared to a single p-SnO or n-SnO2 charge trapping layer (CTL), the heterojunction CTSs demonstrate programmable and erasable characteristics as well as good data retention. Among the two CTSs, the tunneling layer/p-SnO/n-SnO2/blocking layer architecture shows higher program efficiency, more robust data retention, and comparable erase characteristics. The resulting memory window reaches 6.66 V after programming at 13 V/1 ms and erasing at -8 V/1 ms, with the extrapolated ten-year memory window of 4.41 V. This is achieved due to the presence of shallow traps in p-SnO and deep traps in n-SnO2, along with the formation of a built-in electric field in the heterojunction.
Article
Materials Science, Multidisciplinary
Qin Li, Jie Ma, Kun Hu, Haowei Hu
Summary: The properties of In-Ga-Zn-O thin films prepared at different deposition temperatures and annealed in pure hydrogen and nitrogen were investigated. It was found that annealing in pure nitrogen significantly increased the carrier concentration and Hall mobility, while annealing in pure hydrogen resulted in an increase in carrier concentration but a decrease in Hall mobility. Spectroscopic ellipsometry results showed that the increase in carrier concentration is related to the increment of shallow band edge state, while the increasing of deep band edge state leads to a rise in trap density and a reduction in Hall mobility.
Article
Physics, Multidisciplinary
Jin-Seong Park, Hyung-Tak Seo, Jea-Gun Park
Summary: An amorphous IGZO TFT was developed as a precise UV-light sensor, with sensitivity dependent on UV-light intensity and irradiation time. The conductivity shift was found to be related to the oxygen vacancy-induced defect density, while the saturation time of threshold voltage decreased with increasing UV-light intensity.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2021)
Article
Instruments & Instrumentation
Shih-Hung Lin, Chi-Hang Siu, Yuan-Ting Wang, Yao-Chin Wang
Summary: In this study, the flaw detection properties of amorphous In-Ga-Zn-O (IGZO) based active-matrix thin-film transistors (TFTs) on foldable device applications are reported. A noninvasive optoelectronic transforming principle is proposed for flaw pixel inspection, with advantages of ultrahigh resolution, small pixel array, and no contact damage. This method can be applied to foldable substrates with an ultrahigh-definition (UHD) TFT array panel and digital X-ray detectors, showing a good flaw detection rate (>90.1%) and fail detection rate (<4.9%).
SENSORS AND MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Seo-Hyun Moon, Soo-Hyun Bae, Young Ha Kwon, Nak-Jin Seong, Jong-Heon Yang, Yong-Hae Kim, Kyu-Jeong Choi, Chi-Sun Hwang, Sung-Min Yoon
Summary: By controlling the type of oxidants and the indium contents in the ALD process, the performance of IGZO thin-film transistors can be significantly improved, particularly in terms of carrier mobility. Different oxidants and In/Ga ratios can adjust the physical properties of Al2O3 PL and GI, leading to enhanced device performance.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Gyubong Kim
Summary: A multiscale approach is presented to calculate hydrogen diffusion in amorphous In-Ga-Zn-O (a-IGZO), where simulated H diffusion depth is used to evaluate VO concentration and kinetic Monte Carlo simulation is carried out to obtain depth profiles of H diffusion. DFT calculations showed that H diffusion is suppressed when occupying VO defects, and a diffusion function depending on nVo and temperature is obtained fitting the complementary error function to the simulated H diffusion profile.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Chemistry, Analytical
Wen Zhang, Zenghui Fan, Ao Shen, Chengyuan Dong
Summary: The study showed that heat treatments in O-2 or air resulted in higher threshold voltage and off current, lower field-effect mobility, and slightly improved PBS stability for a-IGZO TFTs. On the other hand, annealing processes in vacuum or N-2 had almost no impact on the electrical performance of a-IGZO TFTs, but significantly improved their PBS stability.
Article
Engineering, Electrical & Electronic
Hyun-Jun Jeong, Yoon-Seo Kim, Seok-Goo Jeong, Jin-Seong Park
Summary: Oxide semiconductor thin film transistors (TFTs) have the potential to be used in display and memory devices due to their uniformity and low off-current characteristics. In this study, highly oriented crystalline indium-gallium-zinc oxide (IGZO) thin films and TFTs incorporating such films were fabricated using plasma-enhanced atomic layer deposition (PEALD). The annealing process was conducted at different temperatures, and it was observed that as the annealing temperature increased, device performances and reliability decreased. This study suggests that highly ordered IGZO thin films can be deposited by ALD, and it is possible to manufacture oxide TFTs with excellent electrical performances if the process can retain moderate hydrogen content.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Hyun-Min Ahn, Seo-Hyun Moon, Young-Ha Kwon, Nak-Jin Seong, Kyu-Jeong Choi, Chi-Sun Hwang, Jong-Heon Yang, Yong-Hae Kim, Sung-Min Yoon
Summary: Trench-structured In-Ga-Zn-O vertical thin-film transistors (T-VTFTs) were fabricated with channel length of 400 nm. By optimizing the channel width, T-VTFTs showed field-effect mobility dependent on channel width and exhibited improved immunity against drain-induced barrier lowering compared to conventional mesa-shaped VTFTs.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Nanoscience & Nanotechnology
TaeHyun Hong, Yoon-Seo Kim, Su-Hwan Choi, Jun Hyung Lim, Jin-Seong Park
Summary: In this study, IGZO films with different compositions were synthesized using plasma-enhanced atomic layer deposition (PEALD) technique. The influence of metal composition on the electrical properties was investigated, and the optimal In-Ga-Zn composition range for high-mobility TFTs was determined. In this range, the devices exhibited high mobility, low subthreshold swing, negative initial threshold voltage, and a slight threshold voltage shift under positive bias temperature stability.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Anastasia Glushkova, Harold F. W. Dekkers, Manoj Nag, Jose Ignacio del Agua Borniquel, Jothilingam Ramalingam, Jan Genoe, Paul Heremans, Cedric Rolin
Summary: By optimizing sputtering conditions, we successfully fabricated IGZO thin-film transistors based on different phases, and found that protocrystalline IGZO exhibited the highest TFT performance and best bias stress stability when sputtered at T-sub = 200 degrees C and R-O2 = 20%.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Chihiro Yamamoto, Xinyi He, Takayoshi Katase, Keisuke Ide, Yosuke Goto, Yoshikazu Mizuguchi, Akane Samizo, Makoto Minohara, Shigenori Ueda, Hidenori Hiramatsu, Hideo Hosono, Toshio Kamiya
Summary: This study successfully achieved double switching of charge polarity in tin mono-selenide materials by varying the composition of (Sn1-xSbx)Se, providing a new approach for realizing p-n homojunction devices.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Ceramics
Akira Saitoh, Katsuki Hayashi, Kota Hanzawa, Shigenori Ueda, Shiro Kawachi, Jun-ichi Yamaura, Keisuke Ide, Junghwan Kim, Gregory Tricot, Satoru Matsuishi, Kazuki Mitsui, Tatsuki Shimizu, Masami Mori, Hideo Hosono, Hidenori Hiramatsu
Summary: The origins of coloration in Bi2O3-SiO2, Bi2O3-B2O3, and Bi2O3-P2O5 glasses were investigated, correlating the electronic structure with Bi valence states. The glasses exhibited optical bandgaps and visible absorption bands related to charge transfer between Bi3+ and Bi5+, or plasmonic Bi-0 clusters. These Bi oxide glasses with high transparency and refractive index show potential as replacements for toxic Pb-containing optical glasses.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Multidisciplinary Sciences
Takayoshi Katase, Yudai Takahashi, Xinyi He, Terumasa Tadano, Keisuke Ide, Hideto Yoshida, Shiro Kawachi, Jun-ichi Yamaura, Masato Sasase, Hidenori Hiramatsu, Hideo Hosono, Toshio Kamiya
Summary: This study proposed a design route for a direct three-dimensional to two-dimensional structural phase transition and successfully induced this transition in (Pb1-xSnx)Se alloy epitaxial films. The reversible giant electronic property change occurred during this transition process.
Article
Nanoscience & Nanotechnology
Xinyi He, Jinshuai Chen, Takayoshi Katase, Makoto Minohara, Keisuke Ide, Hidenori Hiramatsu, Hiroshi Kumigashira, Hideo Hosono, Toshio Kamiya
Summary: This study reports the direct growth of metastable cubic (Sn1-xCax)Se films alloyed with CaSe, which have a wider bandgap and higher carrier mobility compared to Sn1-xPbxSe films. The results reveal the potential of high mobility (Sn1-xCax)Se films for semiconductor device applications.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Inorganic & Nuclear
Akihiro Shiraishi, Shigeru Kimura, Xinyi He, Naoto Watanabe, Takayoshi Katase, Keisuke Ide, Makoto Minohara, Kosuke Matsuzaki, Hidenori Hiramatsu, Hiroshi Kumigashira, Hideo Hosono, Toshio Kamiya
Summary: The study focuses on the synthesis and optoelectronic properties of high phase-purity bulk polycrystals of KCoO2-type layered nitrides AETMN2 (AE= Sr, Ba; and TM= Ti, Zr, Hf). The materials exhibit n-type semiconductor behavior with different optical band gaps, and BaHfN2 shows nondegenerated electron conduction along with weak ferromagnetic behavior. Density functional theory calculations are used to explain the mechanism of carrier generation and impurity incorporation in the materials.
INORGANIC CHEMISTRY
(2022)
Article
Nanoscience & Nanotechnology
Yusaku Nishimura, Xinyi He, Takayoshi Katase, Terumasa Tadano, Keisuke Ide, Suguru Kitani, Kota Hanzawa, Shigenori Ueda, Hidenori Hiramatsu, Hitoshi Kawaji, Hideo Hosono, Toshio Kamiya
Summary: This research reports a method of controlling thermal conductivity through a reversible 3D to 2D crystal structure transition, and achieves a large modulation of thermal conductivity in (Pb1-xSnx)Se material. By strong phonon scattering and electronic phase transition, the lattice thermal conductivity and electronic thermal conductivity can be decreased.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Xinyi He, Haoyun Zhang, Takumi Nose, Takayoshi Katase, Terumasa Tadano, Keisuke Ide, Shigenori Ueda, Hidenori Hiramatsu, Hideo Hosono, Toshio Kamiya
Summary: A strategy to achieve high electrical conductivity and low thermal conductivity is reported for polycrystalline SnSe by substituting Te ions. The Te ion substitution leads to high electrical conductivity and reduced thermal conductivity, improving the performance of polycrystalline SnSe.
Article
Physics, Applied
Keisuke Ide, Naoto Watanabe, Takayoshi Katase, Masato Sasase, Junghwan Kim, Shigenori Ueda, Koji Horiba, Hiroshi Kumigashira, Hidenori Hiramatsu, Hideo Hosono, Toshio Kamiya
Summary: In this study, LEDs were fabricated on glass substrates using amorphous oxide semiconductor materials as emission layers. Rare-earth-doped AOS films were employed, and the LEDs emitted clear red, green, and pink luminescence even in the ambient environment. Resonance photoelectron spectroscopy revealed different emission mechanisms for each rare-earth dopant. This study provides opportunities for the advancement of flexible display technologies in harsh environments.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Xinyi He, Seiya Nomoto, Takehito Komatsu, Takayoshi Katase, Terumasa Tadano, Suguru Kitani, Hideto Yoshida, Takafumi Yamamoto, Hiroshi Mizoguchi, Keisuke Ide, Hidenori Hiramatsu, Hitoshi Kawaji, Hideo Hosono, Toshio Kamiya
Summary: A new approach using hydride anion (H-) substitution for oxide ion is proposed to enhance the ZT value of thermoelectric oxide SrTiO3, achieving environmentally friendly and high-energy conversion efficiency.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Zhongxu Hu, Mari Hiramatsu, Xinyi He, Takayoshi Katase, Terumasa Tadano, Keisuke Ide, Hidenori Hiramatsu, Hideo Hosono, Toshio Kamiya
Summary: We demonstrated a reversible 2D-3D crystal structure transition and thermal conductivity switching in (Sn1-xPbx)S bulk polycrystals. The direct phase boundary between the 2D and 3D structures does not exist under thermal equilibrium conditions, but by using a non-equilibrium synthesis process, the phase boundary can be formed. This transition has potential applications in developing thermal management materials.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Zhongxu Hu, Mari Hiramatsu, Xinyi He, Takayoshi Katase, Terumasa Tadano, Keisuke Ide, Hidenori Hiramatsu, Hideo Hosono, Toshio Kamiya
Summary: We demonstrated a reversible 2D to 3D crystal structure transition and thermal conductivity switching in (Sn1-xPbx)S bulk polycrystals above room temperature. By applying a non-equilibrium synthesis process, we formed a direct phase boundary between the 2D and 3D structures in the Pb-rich (Sn0.2Pb0.8)S, which showed a reversible 2D-3D structural phase transition at around 573 K. This transition temperature is much higher than previously reported and has the potential to accelerate the development of thermal management materials.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
M. Hiraishi, H. Okabe, A. Koda, R. Kadono, T. Ohsawa, N. Ohashi, K. Ide, T. Kamiya, H. Hosono
Summary: The local electronic structure of muons in single-crystalline 0-Ga2O3 was investigated using muon spin rotation/relaxation (mu SR). Two distinct muon states, quasistatic muons (Mu1) and fast-moving muons (Mu2), were identified. Mu1 and Mu2 correspond to the relaxed-excited states associated with the donor and acceptor levels predicted by density functional theory (DFT) calculations for interstitial H. Mu1 is found to be in an OMu-bonded state with three-coordinated oxygen, similar to the thermal equilibrium state of H, and acts as an electron donor. Mu2 is considered to be in the hydride state (Mu-) and undergoes fast diffusion motion through the short-lived neutral state due to charge exchange reactions with conduction electrons (Mu- F Mu0 + e-).
Article
Engineering, Electrical & Electronic
Kaiwen Li, Atsushi Shimizu, Xinyi He, Keisuke Ide, Kota Hanzawa, Kosuke Matsuzaki, Takayoshi Katase, Hidenori Hiramatsu, Hideo Hosono, Qun Zhang, Toshio Kamiya
Summary: In this study, the intrinsic physical properties of polycrystalline Zn3N2 thin films were investigated by suppressing donor impurities. It was found that grain boundary scattering significantly affected the mobility in this nondegenerate Zn3N2 thin film. The mobility of this film, reaching 340 cm(2) V-1 s(-1), was comparable to epitaxial thin films, indicating its potential as a transistor active layer material.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
