Publications by authors named "Rihui Yao"

As the competition intensifies in enhancing the integration and performance of integrated circuits, in accordance with the famous Moore's Law, higher performance and smaller size requirements are imposed on the dielectric layers in electronic devices. Compared to vacuum methods, the production cost of preparing dielectric layers via solution methods is lower, and the preparation cycle is shorter. This paper utilizes a low-temperature self-exothermic reaction based on the solution method to prepare high-performance AlO dielectric thin films that are compatible with flexible substrates.

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  • The article investigates the ideal pulsed laser energy density for creating MoS films using pulsed laser deposition (PLD) and finds that 100 mJ·cm is the most effective setting.
  • It reports that films produced at this energy density exhibit superior surface morphology and crystallization, specifically showing a high-crystallized 2H-MoS phase with strong (002) alignment.
  • Additionally, the study highlights that the resulting Si/MoS heterojunction demonstrates a voltage of 0.61 V and a rectification ratio of 457.0 under the optimal conditions.
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In this study, a KrF excimer laser with a high-absorption coefficient in metal oxide films and a wavelength of 248 nm was selected for the post-processing of a film and metal oxide thin film transistor (MOTFT). Due to the poor negative bias illumination stress (NBIS) stability of indium gallium zinc oxide thin film transistor (IGZO-TFT) devices, terbium-doped Tb:InO material was selected as the target of this study. The XPS test revealed the presence of both Tb and Tb ions in the Tb:InO film.

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In this report, an ammonium metatungstate (AMT) and ferrous chloride [Fe(II)Cl] electrochromic liquid (ECL) was synthesized using a hydrothermal method, with DO used as the solvent instead of HO. The results show that the use of DO can improve the stability and performance of ECLs. The hydrogen evolution process in electrochromic devices (ECDs) filled with ECL becomes more difficult, while the material exchange process becomes easier.

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In recent years, more and more attention has been paid to flexible thin-film transistors (TFTs). Therefore, we combined HfMgTiYZrO high-entropy metal oxide and poly(vinyl alcohol) (PVA) organic material to prepare a flexible dielectric layer. We fabricated metal-insulator-metal (MIM) and TFT devices and carried out flexible tests.

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A printable, flexible display panel is an important trend in the field of information display, which requires better mechanical and electrical properties of device materials. Polymer-metal oxide composite materials are promising in the functional layer of a thin-film transistor (TFT) and can be sufficiently fabricated by polymer-metal salt solution systems through the sol-gel process. For the development of polymer-metal oxide composite ink, it is necessary to study the film-forming mechanism of the composite film during solidification, which is an important reference in ink component design.

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Background: Electrochromic materials can dynamically change their optical properties (such as transmittance, absorbance, and reflectance under the action of an applied voltage, and their research and application in the visible band have been widely concerned. In recent years, with the continuous development of electrochromic technology, the related research has been gradually extended to the infrared region.

Objective: This invited review aims to provide an overview of the current status of several inorganic infrared electrochromic materials, to provide some references for future research, and to promote the research and application of electrochromic technology in the infrared region.

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Article Synopsis
  • Microelectronic devices are advancing quickly in terms of portability and usability, highlighting the need for precise material deposition methods.
  • Electrohydrodynamic printing is gaining attention as a cutting-edge technique for creating high-density microelectronic components, allowing for noncontact, direct printing of materials.
  • This study demonstrates improved performance of printed graphene by reducing line width and resistivity through hydrophobic surface treatment, resulting in a supercapacitor with significantly enhanced capacitance and durability.
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Electrochromic materials have been considered as a new way to achieve energy savings in the building sector due to their potential applications in smart windows, cars, aircrafts, etc. However, the high cost of manufacturing ECDs using the conventional manufacturing methods has limited its commercialization. It is the advantages of low cost as well as resource saving, green environment protection, flexibility and large area production that make printing electronic technology fit for manufacturing electrochromic devices.

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  • Flexible electronic technology is a major research area, especially with the rise of wearable devices that utilize flexible sensors to detect environmental and biological stimuli.
  • The development of high-performance flexible pressure sensors involves not only new materials but also innovative microstructure designs that enhance sensor performance, making it a focus of scientific study.
  • This paper reviews recent advancements in flexible pressure sensors, covering their processing methods, characteristics, and application scenarios, while also addressing future challenges and development opportunities in the field.
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Even though electrochromism has been around for more than 50 years, it still has several issues. Multi-layered films, high manufacturing costs, and a short lifetime are present in existing electrochromic devices. We demonstrate a unique high-performance device with a basic structure and no solid electrochromic sheets in this work.

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The unbalanced evaporation of solvents in low-temperature sintered inks for printed electronics leads to a series of problems in the actual printing process, including printed pattern distortion, surface cracking, and the coffee ring effect, which has become a serious obstacle to this technique. Here, we present a comprehensive investigation of the influence of the solvent composition, environmental, and sintering conditions on the complicated pattern formation process of reactive silver inks. The results first showed that only inks with a certain wettability of solvents could form well-defined patterns.

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  • Capacitors, particularly MIM capacitors with multiple metal oxides, are essential for high integration in modern electronic devices due to their high capacitance density and small thickness.
  • Using a combination of zirconia, yttria, magnesium oxide, alumina, and hafnium oxide, researchers optimized dielectric layers to improve performance in leakage current, capacitance density, and transmittance.
  • The resulting multi-component films demonstrated low roughness and good transmittance, with specific oxide combinations showing significant improvements in leakage current and capacitance density, indicating their potential for advanced applications in highly integrated electronics.
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Recently, tin oxide (SnO) has been the preferred thin film material for semiconductor devices such as thin-film transistors (TFTs) due to its low cost, non-toxicity, and superior electrical performance. However, the high oxygen vacancy (V) concentration leads to poor performance of SnO thin films and devices. In this paper, with tetraethyl orthosilicate (TEOS) as the Si source, which can decompose to release heat and supply energy when annealing, Si doped SnO (STO) films and inverted staggered STO TFTs were successfully fabricated by a solution method.

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  • EHD printing is an eco-friendly and efficient method for creating electronic devices with very fine wire widths under 50 μm, especially useful for silver electrodes.
  • A comparison between UV treatment and oxygen plasma treatment showed that oxygen plasma enhances wettability and uniformity of glass substrates.
  • Optimization of annealing temperature revealed that 200 °C yields the best conductivity, and after refining the EHD printing process, the silver electrode achieved a line width of 19.42 μm and high conductivity, showcasing its potential for advanced electronics.
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Flexible and fully transparent thin film transistors (TFT) were fabricated via room temperature processes. The fabricated TFT on the PEN exhibited excellent performance, including a saturation mobility (μ) of 7.9 cm/V·s, an I/I ratio of 4.

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The active layer of metal oxide semiconductor thin film transistor (MOS-TFT) prepared by solution method, with the advantages of being a low cost and simple preparation process, usually needs heat treatment to improve its performance. Laser treatment has the advantages of high energy, fast speed, less damage to the substrate and controllable treatment area, which is more suitable for flexible and large-scale roll-to-roll preparation than thermal treatment. This paper mainly introduces the basic principle of active layer thin films prepared by laser treatment solution, including laser photochemical cracking of metastable bonds, laser thermal effect, photoactivation effect and laser sintering of nanoparticles.

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Silver nanowire (AgNW) conductive film fabricated by solution processing was investigated as an alternative to indium tin oxide (ITO) in flexible transparent electrodes. In this paper, we studied a facile and effective method by electrodepositing AlO on the surface of AgNWs. As a result, flexible transparent electrodes with improved stability could be obtained by electrodepositing AlO.

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The praseodymium-doped indium-zinc-oxide (PrIZO) thin film transistor (TFT) shows broad application prospects in the new generation of display technologies due to its high performance and high stability. However, traditional device performance evaluation methods need to be carried out after the end of the entire preparation process, which leads to the high-performance device preparation process that takes a lot of time and costs. Therefore, there is a lack of effective methods to optimize the device preparation process.

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Amorphous metal oxide has been a popular choice for thin film material in recent years due to its high uniformity. The dielectric layer is one of the core materials of the thin film transistor (TFT), and it affects the ability of charges storage in TFT. There is a conflict between a high relative dielectric constant and a wide band gap, so we solved this problem by using multiple metals to increase the entropy of the system.

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Polymer/oxide hybrid thin films, which have excellent electrical and mechanical performance, can be effectively fabricated through the sol-gel process, showing great potential in the future printed electronics. However, gelation of polymer/oxide ink systems can easily occur during a thermal process in which case capillary stress can lead to the crack of printed films due to the long period of stress accumulation. To solve this problem, the effect of different solvent systems on formed PAM/ZrO hybrid films, which were printed by piezoelectric printing, was studied in this paper, including single solvent systems of glycol and binary solvent systems of glycol and water.

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High-performance amorphous oxide semiconductor thin film transistors (AOS-TFT) with copper (Cu) electrodes are of great significance for next-generation large-size, high-refresh rate and high-resolution panel display technology. In this work, using rare earth dopant, neodymium-doped indium-zinc-oxide (NdIZO) film was optimized as the active layer of TFT with Cu source and drain (S/D) electrodes. Under the guidance of the Taguchi orthogonal design method from Minitab software, the semiconductor characteristics were evaluated by microwave photoconductivity decay (μ-PCD) measurement.

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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.

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In this work, we performed a systematic study of the physical properties of amorphous Indium-Gallium-Zinc Oxide (a-IGZO) films prepared under various deposition pressures, O2/(Ar+O2) flow ratios, and annealing temperatures. X-ray reflectivity (XRR) and microwave photoconductivity decay (μ-PCD) measurements were conducted to evaluate the quality of a-IGZO films. The results showed that the process conditions have a substantial impact on the film densities and defect states, which in turn affect the performance of the final thin-film transistors (TFT) device.

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In this paper, the effects of annealing temperature and other process parameters on spin-coated indium oxide thin film transistors (InO-TFTs) were studied. The research shows that plasma pretreatment of glass substrate can improve the hydrophilicity of glass substrate and stability of the spin-coating process. With Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analysis, it is found that InO thin films prepared by the spin coating method are amorphous, and have little organic residue when the annealing temperature ranges from 200 to 300 °C.

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