• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.505-510
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• 2012

Cobalt oxide nanostructure materials have been prepared by adding several concentrations of spectator Ni ions in solution, and analyzed by electron microscopy, X-day diffraction, calorimetry/thermogravimetric analysis, UV-vis absorption, Raman, and X-ray photoelectron spectroscopy. The electron microscopy results show that the morphology of the nanostructures is dramatically altered by changing the concentration of spectator ions. The bulk XRD patterns of $350^{\circ}C$-annealed samples indicate that the structure of the cobalt oxide is all of cubic Fd-3m $Co_3O_4$, and show that the major XRD peaks shift slightly with the concentration of Ni ions. In Raman spectroscopy, we can confirm the XRD data through a more obvious change in peak position, broadness, and intensity. For the un-sputtered samples in the XPS measurement process, the XPS peaks of Co 2p and O 1s for the samples prepared without Ni ions exhibit higher binding energies than those for the sample prepared with Ni ions. Upon $Ar^+$ ion sputtering, we found $Co_3O_4$ reduces to CoO, on the basis of XPS data. Our study could be further applied to controlling morphology and surface oxidation state.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.226-226
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• 2012

The electronic and electrical properties of nickel oxide (NiO) thin films were investigated by reflection electron energy loss spectroscopy (REELS), x-ray photoelectron spectroscopy (XPS), and Hall Effect measurements. REELS spectra revealed that the band gap of the NiO thin film was increased from 3.50 eV to 4.02 eV after annealing the sample at $800^{\circ}C$. Our XPS spectra showed that the amount of Ni2O3 decreased after annealing. The Hall Effect results showed that the doping type of the sample changed from n type to p type after annealing. The resistivity decreased drastically from $4.6{\times}10^3$ to $3.5{\times}10^{-2}$ ${\Omega}{\cdot}cm$. The mobility of NiO thin films was changed form $3.29{\times}10^3$ to $3.09{\times}10^5cm^2/V{\cdot}s$. Our results showed that the annealing temperature plays a crucial role in increasing the carrier concentration and the mobility which leads to lowering resistivity of NiO thin films.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.360.2-360.2
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• 2016

CuSn thin films were fabricated by rf magnetron co-sputtering method on the Si(100) substrate for evaluation of the antibacterial effect. The co-sputtering process was performed with different rf powers and sputtering times to regulate the thickness of the films and relative atomic ratio of Cu to Sn. The physicochemical properties of the CuSn thin films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), Optical microscope (OM), 4-point probe, and antibacterial test. An antibacterial test was conducted with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as changing contact times between CuSn fillms and bacteria suspension. We compared to the crystalline structures of films before sterilization and after sterilization by XRD measurement. The changes of oxidation states of Cu and Sn and the chemical environment of films before and after antibacterial test were investigated with high resolution XPS spectra in the regions of Cu 2p, Cu LMM, and Sn 3d. After antibacterial test, the morphology of the films was checked with an OM images. The electrical properties of the CuSn films such as surface resistance and conductivity were measured by using 4-point probe.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.374.1-374.1
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• 2016

Copper and zinc are well known elements with antibacterial effect. So in this research, Cu and Zn (CZ) nanofibers (NFs) were fabricated by electrospinning method using polyvinylpyrrolidone (PVP) for adjusting viscosity. The CZ/PVP precursor solutions were prepared with copper sulfate pentahydrate, and zinc acetate dihydrate. Distilled water was used for solvent and PVP was used to regulate the viscosity of precursor solution. The CZ/PVP NF composites were obtained by electrospinning method using the precursor solution. The average diameter of obtained CZ/PVP NFs was determined by optical microscopy using Motic image plus 2.0 program and was found to be 490 nm. The chemical environment of the obtained CZ/PVP NF composites was investigated with X-ray photoelectron spectroscopy (XPS). After heating the obtained CZ/PVP NF composites at 353 K, the solvent was removed. The characteristic C 1s, Cu 2p, and Zn 2p core level XPS peaks were observed. After calcination the CZ/PVP NF composites at 873 K in Ar environment for 5 hrs, PVP was decomposed at this temperature and CZ NF was obtained. This was confirmed by decreasing the intensity of C 1s.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.236.2-236.2
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• 2015

The copper-zinc(Cu-Zn) nanofiber was prepared by electrospinning method. The Cu/PVP (polyvinylpyrrolidone) and Zn/PVP precursor solutions were prepared by dissolution of copper sulfate and zinc acetate in methanol, respectively. The PVP was used to control the viscosity of the precursor solutions. The optimized ratio for the Cu/PVP and Zn/PVP nanofibers was determined separately. Then the suitable ratio of the precursor solutions was applied for fabrication of Cu/Zn/PVP nanofiber. For the electrospinning method, the precursor solutions were filled in a syringe. The distance between metallic needle on the syringe and collector was fixed at 16 cm and the voltage was applied on the tip was 13.0 kV. And the as-spun nanofiber was heated at 353K for removal of residual solvent. Then the heated nanofibers were calcined at 973K to decompose PVP. The obtained Cu, Zn, and Cu-Zn nanofibers were investigated with X-ray photoelectron spectroscopy (XPS) for the chemical properties, scanning electron microscopy (SEM) for the morphologies, and X-ray diffraction (XRD) to characterize the crystallinity and phase of nanofibers.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.45-48
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• 2000

High dielectric (Ba,Sr)TiO$_3$thin films were etched in an inductively coupled plasma (ICP) as a function of C1$_2$/Ar gas mixing ratio. Under Cl$_2$(20)/Ar(80), the maximum etch rate of the BST films was 400$\AA$/min and selectivities of BST to Pt and PR were obtained 0.4 and 0.2, respectively. We investigated the etched surface of BST by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and x-ray diffraction (XRD). From the result of XPS analysis, we found that residues of Ba-Cl and Ti-Cl bonds remained on the surface of the etched BST for high boiling point. The surface roughness decreased as Cl$_2$increases in C1$_2$/Ar plasma because of non-volatile etching products. This changed the nature of the crystallinity of BST. From the result of XRD analysis, the crystallinity of etched BST film maintained as similar to as-deposited BST under Ar only and Cl$_2$(20)/Ar(80). However, (100) orientation intensity of etched BST film abruptly decreased at Cl$_2$only plasma. It was caused that Cl compounds were redeposited on the etched BST surface and damaged to crystallinity of BST film during the etch process.

• 한국안광학회지
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• 제3권1호
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• pp.115-120
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• 1998

RF(radio-frequency) magnetron 스퍼터링 장치에 질소가스와 아르곤가스를 동시에 주입하면서 Ti 타켓을 스퍼터링하여 $TiN_x$ 박막을 유리기판위에 제작하였다. 박막제작시 RF power supply 출력을 240W로, 증착기 내부의 온도는 $200^{\circ}C$를 유지하였다. $TiN_x$ 박막은 알곤 가스를 20sccm으로 고정시킨 상태에서 질소를 3sccm부터 9sccm까지 변화시켜가며 증착시켰다. 이때 박막의 화학적 조성과 성분비를 분석하기 위하여 XPS를 사용하였다.

• 한국진공학회지
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• 제6권4호
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• pp.314-320
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• 1997

XPS를 이용하여 공기 중에 노출된 TiN박막과 상온 증착된 Cu사이의 계면에서의 화학적 반응과 전자 구조적인 변화를 조사하였다. Ti(2p), O(1s), N(1s), Cu(2p) core-level과 Cu LMM Auger line의 spectrum을 보면, Cu의 증착두께가 증가하여도 peak의 위치 뿐만 아니라 line shape이 전혀 변화하지 않는다. 그리고 XPS에 의한 valence bands를 보아도 전 혀 변화가 없다. 이것은 공기 중에 노출된 TiN박막과 Cu사이의 계면에서 Cu화합물의 어떠 한 형태도 존재하지 않을 뿐만 아니라 전자 구조적인 면에서도 전혀 변화가 없음을 의미한 다. 계면에서 Cu가 화학적 반응을 일으키지 않는 것은 계면접합력을 나쁘게 하는 요인이 된 다. 우리는 계면에서의 화학 반응 또는 전자구조의 변화에 대한 연구를 통하여 Cu와 TiN박 막의 계면접합력을 이해할 수 있었다.

• 한국진공학회지
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• 제6권4호
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• pp.321-325
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• 1997

LCD용 칼라 필터를 제작하는 방법으로 감광성 고분자(photosensitive polymer)에 광 리소그라피(photolithography)기술이 많이 이용되어지고 있다. 이로 인해 감광성 고분자 표 면의 물리적, 화학적 성질이 변하게 되는데, 이는 후속 공정인 플라즈마 식각이나 ITO 전극 의 증착 등에도 많은 영향을 주므로, 각 공정에 따른 이들 고분자의 표면 연구는 매우 중요 하다. 본 논문에서는 blue 칼라 필터의 고분자 표면에 대한 연구를 SIMS와 XPS를 이용하 여 수행하였으며, 표면의 거칠기 변화를 AFM을 통해 관찰하였다. SIMS와 XPS결과로부터 초기 공정인 blue 칼라 필터를 스핀 코팅하고 pre bake한 상태에서는 주로 칼라 필터의 주 성분인 단량체와 결합제의 고분자 물질이 표면에 드러나 있다가, 노광 과정을 거치고 post bake한 시료에서는 색깔을 내는 안료 성분이 표면에 드러남을 확인하였고, AFM을 통해서 는 post bake후에 표면에 더 거칠어 짐을 관찰하였다.

• 한국전기전자재료학회논문지
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• 제11권6호
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• pp.472-476
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• 1998

The surface reactions of silica film($SiO_2-P_2O_5-B_2O_3-GeO_2$) with fluorocarbon plasma has been studied by using angle -resolved x-ray photoelectron spectroscopy(XPS). It has been confirmed that residual carbon consists of C-C and C-CFx bonds and fluorine mainly binds silicon in the case of etched silica by using $CF_4$ gas plasma. The surface reaction of silica with various fluorocarbon gases, such as $CF_4,C_2F_6 and CHF_3$ were investigated. XPS results showed that though the etching gases were changed, the elements and binding states of the residual layers on the etched silica by using various fluorocarbon gas plasma were nearly the same . This seems to be due to the high volatility of byproducts, that is, $SiF_4 and CO_2$ etc..