http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kim, YoungSu,Kim, GwangSeok,Lee, SangYul American Scientific Publishers 2011 Journal of Nanoscience and Nanotechnology Vol.11 No.10
<P>In this study, CrZrN films were synthesized by unbalanced magnetron sputtering (UBM) under various N2 partial pressures and their characteristics such as crystalline structure, surface morphology, microstructure and mechanical properties as a function of the N2 partial pressures were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nanoindentation, wear tests, and corrosion tests. Results revealed that, with increasing the N2 partial pressure from 0.05 to 0.21 Pa, the nitrogen content of the films increased from approximately 40.9 to 53.7 at%, the deposition rate decreased from approximately 100 to 59 nm/min and the surface roughness (Rms value) was increased from approximately 0.57 to 1.79 nm. The Cr37.3-Zr9.0-N53.7 film has the highest hardness, elastic modulus, and plastic deformation resistance of 36 GPa, 380 GPa, and 0.41, respectively. The Cr37.3-Zr9.0-N53.7 film also has the lowest friction coefficient and wear rate of 0.19 and 3.01 (10(-6)m3/Nm) at room temperature. In addition, the potentiodynamic test results showed the corrosion resistance of the CrZrN films became increased significantly and their corrosion current density (i(corr)), corrosion potentials (Ecorr) and corrosion rate decreased with increasing N2 partial pressure.</P>
Transfer-Free Growth of Multilayer Graphene Using Self-Assembled Monolayers
Yang, Gwangseok,Kim, Hong-Yeol,Jang, Soohwan,Kim, Jihyun American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.40
<P>Large-area graphene needs to be directly synthesized on the desired substrates without using a transfer process so that it can easily be used in industrial applications. However, the development of a direct method for graphene growth on an arbitrary substrate remains challenging. Here, we demonstrate a bottom-up and transfer-free growth method for preparing multilayer graphene using a self-assembled monolayer (trimethoxy phenylsilane) as the carbon source. Graphene was directly grown on various substrates such as SiO2/Si, quartz, GaN, and textured Si by a simple thermal annealing process employing catalytic metal encapsulation. To determine the optimal growth conditions, experimental parameters such as the choice of catalytic metal, growth temperatures, and gas flow rate were investigated. The optical transmittance at 550 nm and the sheet resistance of the prepared transfer-free graphene are 84.3% and 3500 Omega/square, respectively. The synthesized graphene samples were fabricated into chemical sensors. High and fast responses to both NO2 and NH3 gas molecules were observed. The transfer-free graphene growth method proposed in this study is highly compatible with previously established fabrication systems;. thereby opening up new possibilities for using graphene in versatile applications.</P>
Single CdTe microwire photodetectors grown by close-spaced sublimation method.
Yang, Gwangseok,Kim, Byung-Jae,Kim, Donghwan,Kim, Jihyun Optical Society of America 2014 Optics express Vol.22 No.16
<P>We demonstrate single CdTe microwire field-effect transistors (FETs) that are highly sensitive to ultraviolet (UV) light. Dense CdTe microwires were catalytically grown using a close-spaced sublimation system. Structural, morphological and transport properties in conjunction with the optoelectronic properties were systemically investigated. CdTe microwire FETs exhibited p-type behaviors with field-effect mobilities up to 1.1 10(-3) cm2 V(-1) s(-1). Optoelectronic properties of our CdTe microwire FETs were studied under dark and UV-illumination conditions, where photoresponse was highly dependent on the back-gate bias conditions. Our CdTe microwire FET-based photodetectors are promising for high-performance micro-optoelectronic applications.</P>
Self-aligned growth of CdTe photodetectors using a graphene seed layer.
Yang, Gwangseok,Kim, Donghwan,Kim, Jihyun Optical Society of America 2015 Optics express Vol.23 No.19
<P>We demonstrate the self-aligned growth of CdTe photodetectors using graphene as a pre-defined seed layer. Defects were generated in the graphene prior to growth to act as CdTe nucleation sites. Self-aligned CdTe structures were grown selectively on the pre-defined graphene region. The electrical and optoelectrical properties of the photodetectors were systematically analyzed. Our CdTe devices displayed Ohmic behavior with a low sheet resistance of 1.24 ?? 10<sup>8</sup> 곽/sq. Excellent photodetecting performances were achieved, including a high on-off ratio (~2.8), fast response time (10.4 s), and highly reproducible photoresponses. The fabrication method proposed here for these self-aligned device structures proves valuable for the development of next-generation graphene-semiconductor hybrid devices.</P>
비대칭 스퍼터링에 의한 TiAIN/CrN 나노 다층 박막의 합성 및 특성 분석에 관한 연구
김광석(GwangSeok Kim),김범석(Bom Sok Kim),이상율(SangYul Lee) 한국표면공학회 2005 한국표면공학회지 Vol.38 No.6
In this work a multi-layered nanostructured TiAlN/CrN superlattice coatings was synthesized using closed-field unbalanced magnetron sputtering method and the relationships between their superlattice period (1), micro-structure, hardness and elastic modulus were investigated. In addition, wear test at 500℃ and oxidation resistance test at 900℃ were performed 10 investigate high temperature properties of these thin films. The coatings were characterized in terms of microstructure and mechanical properties by transmission electron microscopy (TEM) and nano-indentation test. Results from TEM analysis showed that superlattice periods was inversely proportional to the jig rotation speed. The maximum hardness and elastic modulus of 37 ㎬ and 375 ㎬ were observed at superalttice period of 6.1 ㎚ and 4.4 ㎚, respectively. An higher value of microhardness from TiAlN/CrN thin films than either TiAlN (30 ㎬) or CrN (26 ㎬) was noted while the elastic modulus was approximately an average of TiAlN and CrN films. These enhancement effects in superlattice films could be attributed to the resistance to dislocation glide across interface between the CrN and TiAlN layers. Much improved plastic deformation resistance (H³/E²) of 0.36 from TiAlN/CrN coatings was observed, compared with 0.15 and 0.16 from TiAlN and CrN, respectively. Also the wear resistance at 500℃ was largely increased than those of single TiAlN and CrN coatings and TiAlN/CrN coatings showed much reduced weight gain after exposure at 900℃ for 20 hours.