JSAP Review
Online ISSN : 2437-0061
Current issue
Displaying 1-12 of 12 articles from this issue
Comprehensive Review
  • Tetsuo Kodera
    Article type: Comprehensive Review
    2024 Volume 2024 Article ID: 240101
    Published: 2024
    Released on J-STAGE: March 05, 2024
    JOURNAL OPEN ACCESS

    The development of fault-tolerant quantum computers that can solve diverse, complex, and large-scale problems is highly anticipated. Achieving this requires both high-fidelity and highly-integrated qubits. Research and development is progressing on various physical systems, and semiconductor qubits are one of the leading candidates. This report provides an overview of the fundamental knowledge of semiconductor qubits. Then, it introduces the global research and development trends related to high fidelity, various efforts toward integration, and research and development of peripheral technologies.

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Tutorial Review
  • Haruyoshi Katayama
    Article type: Tutorial Review
    2024 Volume 2024 Article ID: 240201
    Published: 2024
    Released on J-STAGE: February 07, 2024
    JOURNAL OPEN ACCESS

    Infrared detectors onboard earth observation satellites are required to have excellent performance. JAXA is studying the Type II superlattice infrared detector as a next-generation infrared detector to replace the HgCdTe detector widely used in conventional earth observation satellites. This paper describes the principle and current development status of the Type II superlattice infrared detector in JAXA.

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  • Masahiko Kanaoka
    Article type: Tutorial Review
    2024 Volume 2024 Article ID: 240202
    Published: 2024
    Released on J-STAGE: February 28, 2024
    JOURNAL OPEN ACCESS

    Synchrotron radiation facilities, which are compared to giant microscopes, are used for cutting-edge research in various fields because the characteristics of the emitted X-rays enable observations with extremely-high resolution that cannot be achieved with laboratory-scale analytical equipment. High-precision optical elements are indispensable to obtain this high resolution, and the author’s company is the only one that provides a stable supply of X-ray total-reflection mirrors with surfaces smoothed to a remarkable accuracy of less than 2 nm. This paper describes the existence of a unique nanofabrication technology behind this global niche top business, its successful practical application and commercialization, and introduces an example of an application development of the new technology.

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  • Shun-ichiro Ohmi
    Article type: Tutorial Review
    2024 Volume 2024 Article ID: 240203
    Published: 2024
    Released on J-STAGE: February 29, 2024
    JOURNAL OPEN ACCESS
    Supplementary material

    In this article, nonvolatile memory transistors using Hf-based ferroelectric thin films are described. Ferroelectric-gate transistors, metal–oxide–Si field-effect transistors, are explained using ferroelectric HfO2 and HfN thin films, which can be formed directly on the Si substrate as a gate insulator. Furthermore, FeNOS-type nonvolatile memory transistors that is the metal–oxide–nitride–oxide–Si-type flash memory with ferroelectric HfO2 thin films, which achieves precise threshold voltage control using polarization and charge trap characteristics, are explained.

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  • Masaki Uchida, Yusuke Nakazawa, Masashi Kawasaki
    Article type: Tutorial Review
    2024 Volume 2024 Article ID: 240204
    Published: 2024
    Released on J-STAGE: March 06, 2024
    JOURNAL OPEN ACCESS

    Dirac semimetals have a so-called Dirac cone in their three-dimensional bulk electronic structures. They also have a unique bulk–surface coupled electronic state. Consequently, they have attracted growing attention as a material system for next-generation electronics. In this review, we will explain the fundamental features of Cd3As2, a typical Dirac semimetal, and introduce various results ranging from the fabrication of high-quality thin films to the determination of a unique quantum Hall state. We will also summarize future prospects for possible applications.

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  • Toshiro Kaneko
    Article type: Tutorial Review
    2024 Volume 2024 Article ID: 240205
    Published: 2024
    Released on J-STAGE: March 26, 2024
    JOURNAL OPEN ACCESS

    Non-equilibrium plasmas are characterized by high electron temperatures (tens of thousands of degrees) and low gas temperatures (about room temperature), and thereby, are termed as low-temperature plasmas. High-energy electrons collide with gas atoms and molecules to produce ions, excited species, and reactive species to accelerate chemical reactions, which are used in a wide range of environmental, medical, and agricultural applications, such as sterilization, cancer treatment, and plant disease control. Furthermore, they are used in the applications for materials science involving thin film growth and nanomaterial synthesis. Additionally, high reactivity and controllability can be realized by physically controlling the behavior of electrons and ions by means of electric and magnetic fields. In this review, the methods for physically and chemically controlling plasmas are described, and applied research, utilizing controlled non-equilibrium plasmas, is introduced.

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  • Hideki Narita, Teruo Ono
    Article type: Tutorial Review
    2024 Volume 2024 Article ID: 240206
    Published: 2024
    Released on J-STAGE: April 06, 2024
    JOURNAL OPEN ACCESS

    The superconducting diode effect (SDE) is a phenomenon that results in a superconducting state with zero electrical resistance in the forward direction, but a normal conducting state with finite resistance in the reverse direction. The similarity of this effect to the operation of a semiconductor diode, which is one of the building blocks of modern electronic devices. Exploiting the SDE is promising for the development of diodes and rectifiers with ultra-low power consumption. Recently, a method for controlling the zero-field SDE using magnetization has been demonstrated. This opens up new possibilities for using magnetization to control superconductivity. Here, we provide an overview of the SDE and discuss its future prospects.

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Perspective
  • Kosuke Mitarai
    Article type: Perspective
    2024 Volume 2024 Article ID: 240301
    Published: 2024
    Released on J-STAGE: February 07, 2024
    JOURNAL OPEN ACCESS

    In recent years, the rapid advancements in machine learning have significantly influenced its broader application within society. Concurrently, the prospects of utilizing the computational strengths of quantum computers for machine learning have been a focal point since the 2010s. As quantum hardware continues to evolve, a notable shift is occurring toward developing algorithms specifically for current and near-future quantum systems. This article presents a concise overview of machine learning assisted by quantum computing.

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Research Report
  • Miho Tagawa
    Article type: Research Report
    2024 Volume 2024 Article ID: 240401
    Published: 2024
    Released on J-STAGE: January 23, 2024
    JOURNAL OPEN ACCESS

    Inorganic nanoparticles made of inorganic materials are difficult to arrange in an ordered manner and form higher-order structures by themselves. However, surface modification with DNA, which has selective binding properties, as a guiding molecule can control the interaction and binding between nanoparticles to assemble them into desired crystal structures. In this report, the author presents recent work on determining the structural conditions for DNA-functionalized nanoparticle superlattices that can maintain crystalline symmetry not only in the hydrated state but also after drying by precisely characterizing crystallinity using small-angle X-ray scattering.

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  • Jun Tatebayashi, Yasufumi Fujiwara
    Article type: Research Report
    2024 Volume 2024 Article ID: 240402
    Published: 2024
    Released on J-STAGE: February 08, 2024
    JOURNAL OPEN ACCESS

    This paper reviews our recent research about the formation and optical characteristics of GaN:Eu/GaN nanowires (NWs) by organometallic vapor phase epitaxy for application in GaN-based red LEDs. Two types of GaN:Eu/GaN NWs with different configurations are introduced, core–shell and axial geometries. The configuration of GaN:Eu layers on GaN core NWs can be controlled by changing the growth conditions, and affects the properties of Eu luminescence in the GaN NWs. Next, the fabrication process of the NW LEDs towards future possible realization of flexible devices is established, including an etch-back process of the PDMS membranes to expose the top p-GaN contact layers. Finally, a prototype of p-GaN/GaN:Eu/n-GaN NW LEDs on sapphire substrates is fabricated to determine the device characteristics. Sharp red luminescence at room temperature from Eu3+ ions is observed under current injection.

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  • Fumitaro Ishikawa
    Article type: Research Report
    2024 Volume 2024 Article ID: 240403
    Published: 2024
    Released on J-STAGE: February 16, 2024
    JOURNAL OPEN ACCESS

    Using molecular beam epitaxial crystal growth, we synthesized large-capacity, high-quality compound semiconductor GaAs-based nanowires on a 2-inch silicon substrate. In addition, we explored novel nanowire materials through the growth of GaInNAsBi compounds, crystal polymorphism including stable zincblende and metastable hexagonal structures, and material conversion by oxidation. These materials show various potential applications as a light source in the near-infrared band or white light, and exhibit nonlinear optical effects.

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  • Tetsuya Yamamoto, Rajasekaran Palani, Hisashi Kitami, Hisao Makino
    Article type: Research Report
    2024 Volume 2024 Article ID: 240404
    Published: 2024
    Released on J-STAGE: March 23, 2024
    JOURNAL OPEN ACCESS

    We present the size effects on the electrical and optical properties of high Hall mobility transparent conductive oxide (TCO) films, where the size effects were characterized by the disorder parameter. First, we deposited amorphous W-doped In2O3 (IWO) films with thicknesses ranging from 5 to 10 nm on glass substrates using reactive plasma deposition with dc-arc discharge. Then, we obtained polycrystalline IWO films by solid-phase crystallization, and elucidated the dominant factors determining the states of the carrier electrons and their carrier transport of the films. Decreasing the thickness from 10 to 5 nm, while retaining the carrier concentration, leading to a 2D-like films with induced a lattice disorder, resulting in reduced Hall mobility. A theoretically obtained electron–phonon coupling factor, which is found to be governed by the Debye temperature, carrier concentration, and disorder parameter, provided the cause of the above carrier transport behavior. In addition, based on the above electron–phonon coupling factor, we propose theoretical predictions of materials design to achieve high carrier transport ultra-thin TCO films.

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