Effects of Defects on Single-crystal Growth in Metal Thin Film and on …
관련링크
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" Several methods are used to grow crystals, including solution growth, the Czochralski method, and the image furnace method. In our lab, in particular, with the help of the crystal bank, we have developed more than 100 single crystals. Among them, several crystals have demonstrated ferroelastic domains, spintronics properties, and grain-boundary effects (metal crystals).
In the study of spintronics, we investigated the electrical transport characteristics and anomalous Hall effect (AHE) based on hydrogenated Co-doped ZnO. We observed that the existence of Co-H-Co complexes coincided with the appearance of the AHE, which persisted up to room temperature. Recently, we observed an interesting phenomenon from slightly hydrogenated ZnCoO films without ferromagnetic percolation and examining the relationship between the observed phenomenon and the quantum tunneling effect.
It is well known that the resistivity of a metal is governed by electronphonon scattering at room temperature, and by electron-impurity scattering at low temperatures. However, questions remain regarding the quantitative grain-boundary (GB) effect on the resistivity at room temperature. Upon examination of metal single crystals, we determined the degree to which the resistivity of the metal could be reduced by the elimination of the GB effect. Moreover, the resistivity continued to decrease, finally reaching its minimum value with successive iterations of GB reduction. Our results indicated that this approach works not only in bulk single crystals but also in thin films.
Radio-frequency (RF) sputtering usually produces polycrystalline films with numerous GBs. However, we developed a new method to grow a thin metal film without GBs; the resulting film quality was comparable to that produced using molecular beam epitaxy (MBE). This proposed technique also enables the fabrication of micro/nano-mesh structures of Cu electrodes on polyimide substrates for flexible, transparent conducting electrode (TCE) fabrication via ultraviolet (UV)-lithography and wet over-etching techniques. Copper may potentially provide an advantage over silver; however, many questions remain with regard to revealing its full potential.
Single crystal study may resolve these questions and those related to new materials yet to be discovered. Thus, a great adventure opens up, as we continue to explore the world of single crystals."
In the study of spintronics, we investigated the electrical transport characteristics and anomalous Hall effect (AHE) based on hydrogenated Co-doped ZnO. We observed that the existence of Co-H-Co complexes coincided with the appearance of the AHE, which persisted up to room temperature. Recently, we observed an interesting phenomenon from slightly hydrogenated ZnCoO films without ferromagnetic percolation and examining the relationship between the observed phenomenon and the quantum tunneling effect.
It is well known that the resistivity of a metal is governed by electronphonon scattering at room temperature, and by electron-impurity scattering at low temperatures. However, questions remain regarding the quantitative grain-boundary (GB) effect on the resistivity at room temperature. Upon examination of metal single crystals, we determined the degree to which the resistivity of the metal could be reduced by the elimination of the GB effect. Moreover, the resistivity continued to decrease, finally reaching its minimum value with successive iterations of GB reduction. Our results indicated that this approach works not only in bulk single crystals but also in thin films.
Radio-frequency (RF) sputtering usually produces polycrystalline films with numerous GBs. However, we developed a new method to grow a thin metal film without GBs; the resulting film quality was comparable to that produced using molecular beam epitaxy (MBE). This proposed technique also enables the fabrication of micro/nano-mesh structures of Cu electrodes on polyimide substrates for flexible, transparent conducting electrode (TCE) fabrication via ultraviolet (UV)-lithography and wet over-etching techniques. Copper may potentially provide an advantage over silver; however, many questions remain with regard to revealing its full potential.
Single crystal study may resolve these questions and those related to new materials yet to be discovered. Thus, a great adventure opens up, as we continue to explore the world of single crystals."
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