yonghyeon kim

Mr. yonghyeon kim


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 October 2020 in Nanomaterials
Verified
Journal Article
Open access
PDF file
HCHyeokjoo Choi
Hyeokjoo Choi
SKSeokhun Kwon
Seokhun Kwon
SLSeokwon Lee
Seokwon Lee
YKyonghyeon kim
yonghyeon kim
HKHyunil Kang
Hyunil Kang
WCWonseok Choi
Wonseok Choi
The application of a carbon nanowall (CNW) via transfer is very demanding due to the unusual structure of vertically grown wall-shaped that easily collapses. In addition, direct growth on a device cannot obtain a precision-patterned shape because of the temperature limit of the photoresist (PR). Therefore, in this paper, we demonstrate a new CNW surface micromachining technology capable of direct growth. In order to reduce unexpected damage caused by chemical etching, a physical force was used to etch with the adhesive properties of CNWs that have low adhesion to silicon wafer. To prevent compositing with PR, the CNW was surface modified using oxygen plasma. Since there is a risk of surface-modified CNW (SMCNW) collapse in an ultrasonic treatment, which is a physical force, the CNW was coated with PR. After etching the SMCNW grown on PR uncoated area, PR was lifted off using an acetone solution. The effect on the SMCNW by the lift-off process was investigated. The surface, chemical, and structural properties of PR-removed SMCNW and pristine-SMCNW were compared and showed a minimal difference. Therefore, the CNW surface micromachining technique was considered successful.

31 May 2021 in Energies
Verified
Journal Article
Open access
PDF file
YKyonghyeon kim
yonghyeon kim
HCHyeokjoo Choi
Hyeokjoo Choi
SKSeokhun Kwon
Seokhun Kwon
SLSeokwon Lee
Seokwon Lee
HKHyunil Kang
Hyunil Kang
WCWonseok Choi
Wonseok Choi
This paper examines a microconstruction consisting of nickel (Ni)/chromium (Cr) alloy thin-film. The total length of the microconstruction was 28 mm, the width was 0.2 mm, and the height was designed to be 1 μm. A thin-film of Ni/Cr alloy was co-sputtered on a silicon dioxide wafer patterned with photoresist via a RF magnetron sputtering system. The RF power ratios applied to the 4 inch target of Ni and Cr were 300 W:100 W (3:1), 300 W:150 W (2:1), and 150 W:150 W (1:1). The electrical resistance of the manufactured microconstruction was calculated and measured through Hall measurements. The temperature generated by applying 1–10 V to the microconstruction electrode was observed by using an infrared camera, and was summarized using a linear equation according to the power applied to each sample.