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| Abnormal Grain Growth |
| Our group has suggested the sub-boundary enhanced solid-state wetting mechanism for abnormal grain growth (AGG), which takes place in many metallic systems especially after recrystallization of deformed polycrystals, by the anisotropy of boundary energy instead of boundary mobility. According to this mechanism, sub-boundaries with extremely low energy play a key role in inducing AGG and wetting in solid state can occur under the condition of anisotropy boundary energy which satisfies wetting criteria. To confirm whether the … |
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| Charged Nanoparticles during the Synthesis of GaN Nanostructures |
| According to the theory of charged nanoparticles (TCN) suggested by Hwang et al. (2004, 2010), charged nanoparticles (CNPs) are generated in the gas phase and become building blocks for thin films, nanowires, and other nanostructure in the chemical vapor deposition (CVD) process, which is drastically different from the previous belief that the building blocks for them are believed to be atoms or molecules. Motivated by these studies, the purpose of our work is to confirm whether CNPs are generated in the gas phase during the… |
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| Fabrication of silicon thin-film solar cells by HWCVD |
| Thin films widely used solar cells and thin film transistors. In an effort to suppress the low temperature precipitation of silicon, we added HCl during HWCVD. The crystalline fraction of silicon films was shown to increase systemically with increasing HCl fraction. The crystalline silicon films almost free of amorphous incubation silicon could be deposited directly on a glass substrate by adding an appropriate amount of HCl. And we also improve electrical property of silicon delay time hot wire chemical vapor deposition. Th… |
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| Silicon Thin Film Deposition by Thermal CVD |
| Crystal growth based on an atomic process is well established and described by the terrace, ledge and kink (TLK) model, where the atom adsorbs on a terrace, diffuses to a ledge and finally becomes incorporated in the crystal lattice at the kink. However, our group suggested a theory of charged nanoparticles (TCN), which says that most thin films and nanostructures prepared by CVD, which have been believed to grow by individual atoms or molecules, actually grow by charged nanoparticles. Based on the prediction by the TCN, we … |
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| Silicon Thin Film Deposition by Hot Wire CVD |
| Growth of crystalline thin films has been a key issue in microelectronics, LCD, AMOLED, LED and solar cells. In order to deposit the crystalline Si film at low substrate temperature, our group have studied growth mechanism of Si films in HWCVD system. Our group suggested that the low temperature deposition of crystalline silicon during HWCVD is contributed by crystalline Si gas phase nuclei. To confirm the role of crystalline gas phase nuclei, We captured the hypothetical Si nanoparticles on a transmission electron microscop… |
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| CNPs during the Synthesis of ZnO Nanostructures |
| According to the theory of charged nanoparticles (TCN) suggested by Hwang et al. (2004, 2010), charged nanoparticles (CNPs) are generated in the gas phase and become building blocks for thin films, nanowires, and other nanostructure in the chemical vapor deposition (CVD) process, which is drastically different from the previous belief that the building blocks for them are believed to be atoms or molecules. Motivated by these studies, the purpose of our work is to confirm whether CNPs are generated in the gas phase during the… |
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| Diamond Thin Film Deposition by Hot-Wire CVD |
| Diamond is promising materials in hard coating and semiconductor industries. According to the ‘theory of charged nanoparticles’, nanoparticles are generated during hot wire chemical vapor deposition process in the gas phase nucleation and it can be charged by thermionic emission. The purpose of this study is, based on ‘theory of charged nanoparticles’, to develop the diamond thin film deposition process and understand the mechanisms of diamond thin film formation. To study the new process parameters related charged n… |
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| Charge-Enhanced Diffusion |
| In the chemical vapor deposition (CVD) process, the generation of charged nanoparticles is so general that it appears to be the rule rather than the exception. Therefore, direct evidence of charged cluster is the key in our assumption and has many problem that must be solved. In-situ observation is one of the advanced Transmission Electron Microscope(TEM) Technologies that provide opportunities for us to improve the charge effect for nanoparticles. In electron irradiation in TEM, that makes the charge environment about non-c… |
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| Observation of Diamond Nanoparticles Generated in the Gas Phasse |
| The generation of nanoparticles in the gas phase during the chemical vapor deposition (CVD) process has been frequently reported with their subsequent deposition into films and nanostructures in many systems such as carbon, silicon and zinc oxide. To confirm the generation of diamond nanoparticles in the gas phase under the synthesis condition of diamond films by hot wire CVD (HWCVD), the transmission electron microscope (TEM) grid membrane was exposed for 1 ~ 10 sec using a capturing system and the grid membrane was observe… |
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