Hitoshi Miura

Experimental reproduction of a surface-encircling olivine rim in barred olivine chondrules

Tomoyo Morita, Tomoki Nakamura, Chihiro Koyama, Hitoshi Miura et autres

Barred olivine (BO) chondrules, submillimeter-sized silicate spherules characterized by parallel olivine bars (tabular in 3D) and rims that enclose the surface, record high-temperature processing in the solar nebula. However, their thermal history remains unconstrained due to the lack of experimental reproduction of …

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Direct Synthesis of Multi-Stacked Channels and Doped Source/Drains for TMD CFETs

Shinichi Tanabe, Naoya Okada, Toshifumi Irisawa, Hao Cheng et autres

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Reproduction of ultra-fine oscillatory zoning by direct numerical simulations of step dynamics considering impurity-induced crystal growth inhibition

Hiroki Torii, Hitoshi Miura

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Reduction of carbon impurities in GaN grown by MOCVD using an NH3-plasma source

Hisashi Yamada, Tokio Takahashi, Takahiro Gotow, Naoto Kumagai et autres

In this work, we demonstrate GaN epitaxial growth by plasma-enhanced metalorganic chemical vapor deposition (MOCVD) using trimethylgallium [TMGa, Ga(CH3)3] and ammonia (NH3). Impacts of TMGa, NH3 molar flow rates, and plasma power on surface morphologies and carbon residual impurity concentrations in GaN …

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Wafer-scale formation of MoS2 with controlled thickness and high uniformity via conversion of MoOx using H2S sulfurization and subsequent crystallization

Naoya Okada, Shinichi Tanabe, Hitoshi Miura, Hao Cheng et autres

Achieving uniform, high-quality, and thickness-controlled two-dimensional semiconductor films at the wafer scale remains a critical challenge for practical device integration. This work presents a scalable synthesis method for MoS 2 films on Si/SiO 2 wafers using a three-step conversion (3SC) process. The …

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Numerical Simulation of the Formation Process of Overhanging Structures in SiC Solution Growth to Suppress Solvent Inclusion

Huiqin Zhou, Hitoshi Miura, Yifan Dang, Kentaro Kutsukake et autres

This research presents a study utilizing the phase field model to investigate the formation process of overhanging structures during silicon carbide (SiC) solution crystal growth. The model integrates phase field and diffusion field equations to simulate the evolution of steps and solute …

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Thermal evolution model from cometary nuclei to asteroids considering contraction associated with ice sublimation

Hitoshi Miura

Abstract Comet–asteroid transition (CAT) objects are small solar system bodies that are in the process of evolving from cometary nuclei into asteroids, as they gradually lose volatile substances due to solar heating. The volatile material is mainly water ice, and the time …

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Decoding the formation of barred olivine chondrules: Realization of numerical replication

Hitoshi Miura, Tomoyo Morita, Tomoki Nakamura, Kazumasa WATANABE et autres

Millimeter-sized silicate spherules embedded in primitive meteorites, namely, “chondrules,” are the primary solid component of the early solar nebula. They exhibit distinctive solidification textures, formed through rapid cooling from a molten state. The formation conditions of these textures have primarily been inferred …

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Numerical model for the solidification of a chondrule melt

Hitoshi Miura

In this study, we propose a novel numerical method to simulate the growth dynamics of an olivine single crystal within an isolated, multicomponent silicate droplet. We aimed to theoretically replicate the solidification textures observed in chondrules. The method leverages the phase-field model, …

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Oscillatory zoning of minerals as a fingerprint of impurity-mediated growth

Hiroki Torii, Hitoshi Miura

We propose a kinetic mathematical model of the oscillatory compositional zoning profile recorded in minerals based on the crystal growth suppression induced by impurities. Notably, the presence of a small amount of impurities significantly inhibits crystal growth, and a growth inhibition mechanism …

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Effect of Solution Components on Solvent Inclusion in SiC Solution Growth

Huiqin Zhou, Hitoshi Miura, Yuma Fukami, Yifan Dang et autres

In the solution growth method of silicon carbide, cellular structures and solvent inclusions are fatal defects. This study investigates the mechanism of how cosolvent chromium and additive aluminum influence the formation of cellular structures and inclusions via numerical simulations based on a …

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Quantitative phase-field model for the isothermal solidification of a stoichiometric compound in a ternary liquid

Hitoshi Miura

The phase-field (PF) model is one of the most powerful mathematical models to simulate the solidification of multicomponent alloys. A major challenge faced by the PF model is the treatment of stoichiometric compounds (SCs). In the PF model, compositional derivatives of the …

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