RHEED회절점의 강도변화에 따른 In / Si(111)에 대한 연구

곽호원(Ho-Weon Kwak),이의완(Eui-wan Lee),박동수(Tong-Soo Park),이운환(Woon-Hwan Lee) 한국진공학회(ASCT) 1997 Applied Science and Convergence Technology Vol.6 No.2

Si(111) 7×7표면에 In을 증착시킬 때 기판용도와 증착량에 따른 표면구조의 변화를 RHEED(Reflection High Energy Electron Diffraction) 상 (pattern)과 RHEED상의 회절반점(spot)강도 변화를 관찰하여 조사하였다. Si(111) 기판온도를 400℃로 유지하면서 In을 증착시킬 때 증착량이 약 0.1, 0.3, 0.5 ML에서 각각 √3×√3, √31×√31, 4×1구조가 관찰되기 시작하였다. 기판온도 300°에서는 증착량이 약 0.2ML에서부터 4×1구조가 나타나고 0.8ML이상에서부터는 4×1+√3×√3 혼합구조가 관찰되기 시작하였다. Si(111)-√3×√3구조의 기판온도를 실온으로 유지하면서 In를 증착시킬 때 증착량이 0.25, 0.7ML에서 각각 2×2, √7×√3구조가 나타나기 시작하였다. RHEED 반점의 강도변화를 이용하여 Si(111)-√7×√3구조에서의 In원자의 이탈 과정을 조사한 결과 이탈 에너지는 2.84 eV로 조사되었다. The change of surface structures for the deposition of indium on clean Si(111) surface is investigated as a function of substrate temperature and surface coverage by RHEED. We find that at substrate temperature of 400℃, √3×√3, √31×√31 and 4×1 structures are formed at indium coverages of 0.2, 0.3 and 0.5 ML, respectively. We also find that for the substrate temperature of 300℃, 4×1 structure starts to be formed by 0.2 ML of indium, and the mixed structure of 4×1 and √3×√3is observed for more than 1.0ML. On the other hand, if the indium is deposited on the Si(111)-√3×√3 structure at room temperature, 2×2 and √7×√3 structures are found to form at 0.2 and 0.4 ML, respectively. From the desorption process, the desorption energy of indium in Si √7×√3 structure is observed to be 2.84 eV.

원자흡광분광분석법에 의한 혈청 Zn의 측정

채범석(Bum Suk Tchai),석영건(Young Gunn Suk),박동수(Tong Soo Park) 韓國營養學會 1971 Journal of Nutrition and Health Vol.4 No.3

窒素氣體의 LASER

朴東秀,李義完 慶北大學校 1977 論文集 Vol.24 No.-

An efficient pulsed cross-field molecular nitrogen laser has been constructed as a pump for a tunable dye laser. The laser consits of two plate plexiglas and two Al plate electrodes one of them incorporates a band-saw blade as a multiple electrode structure to ensure an even transverse discharge in flowing nitrogen and produces superradiant emission at 3371Å. Some detailed designs for both the laser channel and electrical trigger circuits with a thyratron are described. At an optimum condition the nitrogen laser produces a 150KW light pulse when operated 15KV, 20 torr and 30 HZ providing a reflection mirror.

고성능 8-14μ적외선검지기

박동수,이의완 慶北大學校 産業開發硏究所 1978 硏究報告 Vol.6 No.-

High performance photovoltaic Infrared detectors for the 8-14μ spectral region have been fabricated with Pb_(1-x)Sn_xTe single crystals by a surface inversion technique. The single crystals were grown in this laboratory, which posess almost perfect single crystal properties. The hole carrier concentrations of the diodes were around 10^18 to 10^19/㎤, the mobilities were the order of close to 10^3 ㎠/volt·sec, the quantum efficiencies were as much high as 45 percent, and the detectvities were nearly 10^11㎝·(㎐^1/2)/W, which are believed to be sufficient charatectristics for application to high performance commercial IR detectors.

Nb-1%Zr, Nb-5%Zr 합금에서 Zirconium과 탄소의 상호작용 및 표면분정

박동수,이원식,채건식 慶北大學校 物理化學硏究所 1984 硏究論文集 Vol.5 No.-

Nb-1% Zr, Nb-5% Zr 합금에서 지르코니움과 탄소의 상호작용 및 표면분정현상을 아르곤 이온종을 부착한 Auger 전자분광기로 연구했다. 고순도(99.996%)니오비움 다결정은 대부분의 탄소와 산소로 크게 부식되어 있었으며, 니오비움 다결정 내부에 함유된 탄소의 화학적 결합상태도 탄화물, 석묵 두가지 상태로 나타났다. 고순도 니오비움 다결정에 소량의 지르코니움(1%, 5%)을 첨가해서 만든 Nb-Zr 합금표면은 화학적으로 안정한 지르코니움 탄화물로 덮혀있고, 그 두께가 약 10Å정도임을 Auger분광자료로 밝혀냈고, 여기에 나타난 지르코니움, 탄소는 Nb-Zr 합금에서 표면 분정된 사실도 밝혀냈다. Nb-Zr 합금을 점진적으로 온도를 올려가면서, 지르코니움이 표면 분정된 양을 측정한 결과 지르코니움은 1300℃ 근방에서 산소는 1100℃ 근방에서 가장 많이 표면분정됨을 알았다. 이상의 실험결과로 탄소 산소로 크게 부식되어 있는 니오비움 다결정에 소량의 지르코니움(1%, 5%)를 첨가하므로서 탄소 산소의 부식을 크게 줄일 수 있음을 알았다. Auger electron spectrosopcy has been used in conjunction with argon ion sputtering in a study of the surface segregation and interaction of carbon with zirconium in Nb-Zr alloys. The result of depth profiling with argon ion sputtering showed that the carbon coverage on the Nb-Zr alloy surfaces was significantly more than that on the Nb polycrystalline surface. The dominant part of these carbon and oxygen was due to segregation from the Nb-Zr alloys. The segregation of zirconium to the Nb-Zr alloy surfaces occured at temperature as low as 900℃ with the maximum occurring around 1100℃. While the maximum depths of zirconium and oxygen segregated from the Nb-Zr alloy at temperature 1100℃ were respectively 5Å and 15Å.

RHEED에 依한 Si(111) 表面 및 Au, Ag, Ge 蒸着量에 따른 表面構造의 調査

朴東秀,鄭燦翊,鄭烝敏,崔鐘武 慶北大學校 自然科學大學 1987 自然科學論文集 Vol.5 No.-

The clean Si(111) and Si(111) surface structures induced by Au, Ag, Ge deposition were investigated by RHEED. cleaning of the sample was done by passing the dc current directly through the sample and the temperatures of the sample were measured by reading the currents. The background vacuum pressure of the RHEED chamber was about 2∼5×10^-10 torr during the experiments. The clean Si(111) 7×7 superlattice surface structure was obtained by heating the sample up to 1,250℃ repeatedly. The Si(111) 7×7 structure was remained from room temperature to 830℃. Above 830℃ the 7×7 structure turned to 1×1 structure. This structure transition was reversible. The 7×7 structure is energetically most stable in spite of its formation at rather high temperture. When Au, Ag and Ge atoms were deposited on the Si(111) 7×7 surface, the dependence of structures and phases on substrate temperatures and deposited coverages was drasical. Au/Si(111) surface has 7×7, 7×7+5×1, α-√3×√3, β-√3×√3 and 6×6 superstructures for the various thickness of Au film and substrate temperatures. Ag/Si(111) surface has √3×√3, √3×√3+3×1, √3×√3+3×1+6×1, 7×7+6×1+3×1 and 7×7+√3×√3 superstructures for the variot thickness of Ag film and substrate temperatures. When Ag was deposited on substrate at temperature ranged between 290℃ and 550℃, Ag rod patterns appeared on the √3×√3 structure induced by Ag deposition. It was considered due to the Stranski-Krastanov growth of Ag. Ge/Si(111) surface has 7×7, 7×7+5×5, 5×5 and 7×7(G3) superstructures for the various thickness of Ge film and substrate temperatures. It was found that the difference of the lattice constant for Si(111) 7×7 and Ge/Si(111) 7×7 and Ge/Si(111) 7×7 is about 3%.

Auger 電子分光에 의한 Ni-Cu, Cu-Ag 表面의 附着硏究

朴東秀,金裕榮,李元植 慶北大學校 産業開發硏究所 1980 硏究報告 Vol.8 No.-

Adhesion for various metals Ni-Cu-Ag after friction was measured in high vacuum chamber. Surfaces were examined with Auger-Electron-Spectroscopy in∼10_-10 torr before and after contact to determine nature of surface changes resulting from adhesive contact. Surfaces were cleaned by standard process and electrical heating for friction and AES studies. Thus, from the experimental results, it should be possible to predict which of two surfaces in contact will undergo attrition. We can see that adhesion depends on elastic moduli, surface energy, heat of sublimation, melting point and cohesive strength.

느린 多價 Ar 이온 생산을 위한 새로운 장치 고안

박동수,이의완,이원식 慶北大學校 1985 論文集 Vol.39 No.-

New apparatus of producing highly charged slow Ar ions by bombarding Ar^4+ ions with a 42MeV and 10nA on the 10^-4 Torr. Ar target is designed. We have a complete discussion of the design considerations and the detailed testing of the apparatus. Single collision conditions are attained at a sufficiently low pressure where P_i becomes constant. Secondary Ar ion current of producing by collision between Ar^4+ ions with a 20MeV and 10nA and 10^-4 Torr Ar target is about 1.77×10 exp (-11) amperes.

PbSnTe 單結晶 成長

朴東秀,李義完 慶北大學校 文理科大學 1978 文理學叢 Vol.5 No.-

The method of refining Pb and Sn, and the growth of PbSnTe single crystal were described. Approximately better than 6N of pure Pb and Sn were obtained by zone refining of 20 passes as 10cm/hr. Fairly large single crystals of Pb_1-xSn_xTe of stoichiometric were grown by a Bridgman method. Zone refining pure Pb and Sn, and commercial pure Te were used in this experiment. The growing rate in 12mm i.d. quartz ampoule was about 10mm/day. The crustal formation was investigated by X-ray Spectrometer and Metal Microscope. The growing facets were(100) plane.

Molybdenum, Niobium 表面特性에 關한 硏究 (Ⅰ) : Ni, Nb, Zr 表面과 酸素와의 相互作用 및 Nb-1% Zr, Nb-5% Zr 合金의 表面分晶 Interaction of oxygen with Ni, Nb and Zr Surfaces and Surface Segregation of Nb-1%Zr and Nb-5% Zr Binary Alloys

朴東秀,孫基洙,金裕榮,李元植 慶北大學校 物理化學硏究所 1981 硏究論文集 Vol.1-2 No.-

Interaction of oxygen with single crystal nickel, polycrystalline niobium and zirconium surfaces, and surface segregation of Nb-Zr(1%) and Nb-Zr(5%) were studied using Auger Electron Spectroscopy. The oxidation rate of Ni was parabolic while that of Zr was cubic. Beside O and C, S was also detected as the dominant impurity of nickel. Sergregation of sulfur to the nickel surface occured at temperature as low as 500℃, hence the segregation of S was limited to a few monolayers near the surface. Segregation of oxigen and zirconium to the Nb-Zr(1%) and Nb-Zr(5%) surfaces occured with the maximum at temperature around 1400℃ while segregation of carbon to these surfaces occured at temperature as low as 1000℃. It was revealed that when surfaces were cooled down to the room temperataytre O/Nb and Zr/Nb for Nb-Zr(5%) were many fold greaterthan for Nb-Zr(1%), in contrary, the situation became reverse when surfaces were spuctered in Ar(10^-2torr). The heat of segregation of zirconium to the surfaces of Nb-Zr(1%) and Nb-Zr(5%) was determined as -0.86KJ/mol. and -1.09KJ/mol. respectively.