• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.114-114
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• 2011

Graphene is the hottest topic in condensed-matter physics due to its unusual electronic structures such as Dirac cones and massless linear dispersions. Graphene can be epitaxially grown on various metal surfaces with chemical vapor deposition (CVD) processes. Such epitaxial graphene shows modified electronic structures caused by substrates. In the method for removal of the effect of substrate, there are bi, tri-layer graphene, gold intercalation, and oxygen intercalation. Here, We will present the changes of geometric and electronic structure of graphene grown on Ru(0001) by oxygen intercalation between graphene and Ru(0001). Using Scanning tunneling microscopy (STM) and spectroscopy (STS), we observed the aspect that the band gap features near the fermi level of graphene on Ru(0001) system is shifted and narrow. Based on the observed results, two effects by intercalated oxygen were considered.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.395-395
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• 2010

RIS(Reactive Ion Scattering)은 저 에너지 이온 빔을 쏘아 표면을 분석하는 방법이다. 분자 동력학 계산(MD simulation) 결과에 따르면 $Cs^+$이온은 두꺼운 얼음 표면에서 산란이 거의 일어나지 않는다. 본 연구에서는 이와 달리 Pt(111)과 Ru(0001) 표면에 생성시킨 두꺼운 얼음 표면에서 $Cs^+$이온 산란 실험이 가능함을 보였다. 한편, RIS signal은 얼음 층이 쌓인 구조나 두께에 따라 영향을 받는데, Ru(0001)과 Pt(111)의 표면에 생성시킨 crystalline water ice에서 시간과 water ice film의 두께가 RIS signal에 어떠한 영향을 미치는지도 조사하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.307-307
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• 2011

Graphene is the hottest topic in condensed-matter physics due to its unusual electronic structures such as Dirac cones and massless linear dispersions. Graphene can be epitaxially grown on various metal surfaces with chemical vapor deposition processes. Such epitaxial graphene shows modified electronic structures caused by substrates. Here, local geometric and electronic structures of graphene grown on Ru(0001) will be presented. Scanning tunneling microscopy (STM) and spectroscopy (STS) was used to reveal energy dependent atomic level topography and position-dependent differential conductance spectra. Both topography and spectra show variations from three different locations in rippled structures caused by lattice mismatch between graphene and substrate. Based on the observed results, structural models for graphene on Ru(0001) system were considered.

• 한국전기화학회:학술대회논문집
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• 2002.04a
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• pp.56-56
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• 2002

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.268-268
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• 2013

Water molecules on a Ru(0001) surface are anomalously acidic compared to bulk water. The observation was made by conducting reactive ion scattering, reflection absorption infrared spectroscopy, and temperature-programmed desorption measurements for the adsorption of ammonia onto a water layer formed on Ru(0001). The study shows that the water molecules in the first intact $H_2O$ bilayer spontaneously release a proton to NH3 adsorbates to produce $NH_4{^+}$. However, such proton transfer does not occur for $H_2O$, OH, and H in a mixed adsorption layer or for $H_2O$ in a thick ice film surface.

• Journal of the Korean Vacuum Society
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• v.22 no.6
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• pp.285-290
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• 2013

Epitaxial graphene on metal substrates provides excellent platforms to study its atomic and electronic structures, and can be grown either by surface segregation of carbon or by chemical vapor deposition. The growth behaviors of the two methods, however, have not been directly compared each other. Here, we studied domain structures of graphene grown by three different methods, surface segregation, post-annealing with adsorbed ethylene, and high-temperature dose of ethylene, using scanning tunneling microscopy. The first two methods resulted in graphene regions with areas of $100nm^2$, whereas the third method showed large area graphene (> $10^4nm^2$) with regular hexagonal Moire patterns, implying that high-temperature dose of ethylene is preferable for further studies on graphene such as additional growth of organic molecules.