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鈴木 誠也; 根本 善弘*; 椎木 菜摘*; 中山 佳子*; 竹口 雅樹*
Annalen der Physik, 535(9), p.2300122_1 - 2300122_12, 2023/09
被引用回数：0 パーセンタイル：0(Physics, Multidisciplinary)Germanene is a two-dimensional (2D) germanium (Ge) analogous of graphene, and its unique topological properties are expected to be a material for next-generation electronics. However, no germanene electronic devices have yet been reported. One of the reasons for this is that germanene is easily oxidized in air due to its lack of chemical stability. Therefore, growing germanene at solid interfaces where it is not oxidized is one of the key ideas for realizing electronic devices based on germanene. In this study, the behavior of Ge at the solid interface at high temperatures was observed by transmission electron microscopy (TEM). To achieve such in situ heating TEM observation, we fabricated a graphene/Ge/graphene encapsulated structure. In situ heating TEM experiments revealed that Ge like droplets moved and coalesced with other Ge droplets, indicating that Ge remained as a liquid phase between graphene layers at temperatures higher than the Ge melting point.
雨倉 宏*; 石川 法人; 大久保 成彰; 中山 佳子*; 三石 和貴*
Nuclear Instruments and Methods in Physics Research B, 269(23), p.2730 - 2733, 2011/12
被引用回数：13 パーセンタイル：69.55(Instruments & Instrumentation)高速重イオン照射による(シリカ中に埋め込まれた)金属ナノ粒子の形状伸長を説明する既存のモデルとして、熱スパイクモデル(ピコ秒の温度上昇を伴う融解とその後の凝固に至るプロセス)がある。このモデルの妥当性を検証するために、融点の大きく異なる金属であるバナジウム(バルク融点1890
C)と亜鉛(バルク融点420C)の金属ナノ粒子の200-MeV Xe照射効果をそれぞれ比較し検討した。その結果、それぞれの融点が異なるにもかかわらず、両者はほぼ同程度の形状伸長を示した。この結果は既存のモデルの修正の必要性を示唆する。シリカの融解と金属ナノ粒子の融解とが同時並行で進行しないことを考慮した修正モデルを提案した。
雨倉 宏*; 石川 法人; 大久保 成彰; Ridgway, M.*; Giulian, R.*; 三石 和貴*; 中山 佳子*; Buchal, C.*; Mantl, S.*; 岸本 直樹*
Physical Review B, 83(20), p.205401_1 - 205401_10, 2011/05
被引用回数：35 パーセンタイル：78.35(Materials Science, Multidisciplinary)シリカに埋め込まれた金属ナノ粒子が高速重イオンの照射方向に形状伸長する現象について研究した。この現象が、イオン照射に伴って形成される欠陥集合体(イオントラック)が重畳することによって間接的に引き起こされる現象なのか、あるいはイオントラックと金属ナノ粒子とが直接相互作用して起きる現象なのかを明らかにすることは、現象解明の重要な鍵となる。本研究では、Znナノ粒子に、イオントラックがほとんど重畳しない低照射量(5.0
10
Xe/cm
)の200-MeV Xeを照射したときにおいても形状伸長が起きることを、検出感度の高い光学的方法を用いて明らかにし、後者のシナリオの可能性の方が高いことを示した。
鈴木 誠也; 根本 善弘*; 椎木 菜摘*; 中山 佳子*; 竹口 雅樹*
no journal, ,
Germanene is a two-dimensional (2D) germanium (Ge) analogous of graphene, and its unique topological properties are expected to be a material for next-generation electronics. Germanene has already been grown on various metal surfaces by molecular beam epitaxy and segregation methods, but transferring it onto insulator surface to fabricate electronic devices is difficult in contrast to graphene. One potential solution is to grow germanene directly on the interface of the insulator. Based on this concept, we have grown germanene at the hexagonal boron nitride (hBN)/Ag(111) interface and demonstrated that germane at the interface is stable. Since hBN is an insulator, direct growth of germanene between hBN provides a promising channel for germanene devices. In this work, we studied the crystallization of Ge between graphene layers at high temperatures using in situ transmission electron microscopy (TEM). Graphene was used as an alternative material for hBN. The Ge sandwiched by 4 layer graphenes was prepared onto an in situ TEM holder using chemical vapor deposited graphene, vacuum deposition of Ge, and wet transfer of graphene. The Raman spectrum of the sample indicated less defective graphene is present after the sample preparation. In situ TEM observation at 1025 degree Celsius revealed that round-shaped Ge moves, deforms, and coalesces at the temperature above the melting point of Ge. The observed motion of Ge indicates that the Ge was in liquid phase and its evaporation was suppressed by graphene layers. Although more novel ideas are needed to achieve 2D crystal growth of Ge at the interface, the present results may provide clues for the future direct growth of germane between hBN layers.
