• Title/Summary/Keyword: Photoelectron spectroscopy

Search Result 1,462, Processing Time 0.035 seconds

Fabrication of CuZn Nanofibers by Electrospinning Method

  • ;Park, Ju-Yeon;Jeong, Eun-Gang;Gang, Yong-Cheol
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2016.02a
    • /
    • pp.374.1-374.1
    • /
    • 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.

  • PDF

Gradational Double Annealing Process for Improvement of Thermal Characteristics of NiCr Thin Films (NiCr 박막의 발열 특성 개선을 위한 순차적 이중 열처리 방법 연구)

  • Kwon, Yong;Noh, Whyo-Sup;Kim, Nam-Hoon;Cho, Dong-You;Park, Jinseong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.18 no.8
    • /
    • pp.714-719
    • /
    • 2005
  • NiCr thin film was deposited by DC magnetron sputtering on $A;_2O_3$/Si substrate with NiCr (80:20) alloy target. NiCr thin films were annealed at $300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C,\;600^{\circ}C,\;and\;700^{\circ}C$ for 6 hr in $H_2$ after annealing at $500^{\circ}C$ for 6hr in air atmosphere, respectively. To analyze NiCr thin film properties, the changes of its micro structure were Investigated through field emission scanning electron microscope (FESEM). X-ray photoelectron spectroscopy (XPS) was used to analyze a surface of NiCr thin film. Resistance of NiCr thin film was measured by 4-point probe technique. The generated heats were measured by infrared thermometer through the application of DC voltage (5 V/l2 V). NiCr thin film treated by gradational double annealing process had uniform and small grains. Maximum temperature generated heat by NiCr micro heater was $173^{\circ}C$. We expect that our results will be a useful reference in the realization of NiCr micro heater.

Effects of Citric Acid as a Complexing Agent on Material Removal in Cu CMP (Cu CMP에서 Citric Acid가 재료 제거에 미치는 영향)

  • Jung Won-Duck;Park Boum-Young;Lee Hyun-Seop;Jeong Hea-Do
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.19 no.10
    • /
    • pp.889-893
    • /
    • 2006
  • Chemical mechanical polishing (CMP) achieves surface planrity through combined mechanical and chemical means. The role of slurry is very important in metal CMP. Slurry used in metal CMP normally consists of oxidizers, complexing agents, corrosion inhibitors and abrasives. This paper investigates the effects of citric acid as a complexing agent for Cu CMP with $H_2O_2$. In order to study chemical effects of citric acid, X-ray photoelectron spectroscopy (XPS) was peformed on Cu sample after etching test. XPS results reveal that CuO, $Cu(OH)_2$ layer decrease but $CU/CU_2O$ layer increase on Cu sample surface. To investigate nanomechanical properties of Cu sample surface, nanoindentation was performed on Cu sample. Results of nanoindentation indicate wear resistance of Cu surface decrease. According to decrease of wear resistance on Cu surface removal rate increases from $285\;{\AA}/min\;to\;8645\;{\AA}/min$ in Cu CMP.

Dry Etching Characteristics of Indium Zinc Oxide Thin Films in Adaptive Coupled Plasma

  • Woo, Jong-Chang;Choi, Chang-Auck;Kim, Chang-Il
    • Transactions on Electrical and Electronic Materials
    • /
    • v.14 no.4
    • /
    • pp.216-220
    • /
    • 2013
  • The etching characteristics of indium zinc oxide (IZO) in $Cl_2/Ar$ plasma were investigated, including the etch rate and selectivity of IZO. The IZO etch rate showed non-monotonic behavior with increasing $Cl_2$ fraction in the $Cl_2/Ar$ plasma, and with increasing source power, bias power, and process pressure. In the $Cl_2/Ar$ (75:25%) gas mixture, a maximum IZO etch rate of 87.6 nm/min and etch selectivity of 1.09 for IZO to $SiO_2$ were obtained. Owing to the relatively low volatility of the by-products formation, ion bombardment was required, in addition to physical sputtering, to obtain high IZO etch rates. The chemical state of the etched surfaces was investigated with X-ray photoelectron spectroscopy. These data suggested that the IZO etch mechanism was ion-enhanced chemical etching.

Correlation Between Arrhenius Equation and Binding Energy by X-ray Photoelectron Spectroscopy

  • Oh, Teresa
    • Transactions on Electrical and Electronic Materials
    • /
    • v.14 no.6
    • /
    • pp.329-333
    • /
    • 2013
  • SiOC films were prepared by capacitively coupled plasma chemical vapor deposition, and the correlation between the binding energy by X-ray photoelectron spectroscopy and Arrhenius equation for ionization energy was studied. The ionization energy decreased with increase of the potential barrier, and then the dielectric constant also decreased. The binding energy decreased with increase of the potential barrier. The dielectric constant and electrical characteristic of SiOC film was obtained by Arrhenius equation. The dielectric constant of SiOC film was decreased by lowering the polarization, which was made from the recombination between opposite polar sites, and the dissociation energy during the deposition. The SiOC film with the lowest dielectric constant had a flat surface, which depended on how carbocations recombined with other broken bonds of precursor molecules, and it became a fine cross-linked structure with low ionization energy, which contributed to decreasing the binding energy by Si 2p, C 1s electron orbital spectra and O 1s electron orbital spectra. The dielectric constant after annealing decreased, owing to the extraction of the $H_2O$ group, and lowering of the polarity.

The Role of Surface Oxide of Metal Nanoparticles on Catalytic Activity of CO Oxidation Unraveled with Ambient Pressure X-ray Photoelectron Spectroscopy

  • Park, Jeong Young
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.02a
    • /
    • pp.132-132
    • /
    • 2013
  • Colloidal synthesis of nanoparticles with well-controlled size, shape, and composition, together with development of in situ surface science characterization tools, such as ambient pressure X-ray photoelectron spectroscopy (APXPS), has brought new opportunities to unravel the surface structure of working catalysts. Recent studies suggest that surface oxides on transition metal nanoparticles play an important role in determining the catalytic activity of CO oxidation. In this talk, I will outline the recent studies on the influence of surface oxides on Rh, Pt, Ru and Co nanoparticles on the catalytic activity of CO oxidation [1-3]. Transition metal nanoparticle model catalysts were synthesized in the presence of poly(vinyl pyrrolidone) polymer capping agent and deposited onto a flat Si support as two-dimensional arrays using the Langmuir-Blodgett deposition technique. APXPS studies exhibited the reversible formation of surface oxides during oxidizing, reducing, and CO oxidation reaction [4]. General trend is that the smaller nanoparticles exhibit the thicker surface oxides, while the bigger ones have the thin oxide layers. Combined with the nature of surface oxides, this trend leads to the different size dependences of catalytic activity. Such in situ observations of metal nanoparticles are useful in identifying the active state of the catalysts during use and, hence, may allow for rational catalyst designs for practical applications. I will also show that the surface oxide can be engineered by using the simple surface treatment such as UV-ozone techniques, which results in changing the catalytic activity [5]. The results suggest an intriguing way to tune catalytic activity via engineering of the nanoscale surface oxide.

  • PDF

Fabrication of WS2-W-WC Embedded Carbon Nanofiber Composites for Supercapacitors (슈퍼 커패시터를 위한 WS2-W-WC가 내장된 탄소나노섬유 복합체의 제조)

  • Lee, Yu-Jin;Ahn, Hyo-Jin
    • Journal of Powder Materials
    • /
    • v.22 no.2
    • /
    • pp.116-121
    • /
    • 2015
  • $WS_2$-W-WC embedded carbon nanofiber composites were fabricated by using electrospinning method for use in high-performance supercapacitors. In order to obtain optimum electrochemical properties for supercapacitors, $WS_2$ nanoparticles were used as precursors and the amounts of $WS_2$ precursors were controlled to 4 wt% (sample A) and 8 wt% (sample B). The morphological, structural, and chemical properties of all samples were investigated by means of field emission photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. These results demonstrated that the embedded phases of samples A and B were changed from $WS_2$ to $WS_2$-W-WC through carbothermal reaction during carbonization process. In particular, sample B presented high specific capacitance (~119.7 F/g at 5 mV/s), good high-rate capacitance (~60.5%), and superb cycleability. The enhanced electrochemical properties of sample B were explained by the synergistic effect of the using 1-D structure supports, increase of specific surface area, and improved conductivity from formation of W and WC phases.

The Study of Silica Surface Reaction with Fluorocarbon Plasma Using Inductively Coupled Plasma (Inductively Coupled Plasma에 의한 fluorocarbon 가스 플라즈마의 실리카 표면 반응 연구)

  • Park, Sang-Ho;Shin, Jang-Uk;Jung, Myung-Young;Choy, Tae-Goo;Kwon, Kwang-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.11 no.6
    • /
    • pp.472-476
    • /
    • 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..

  • PDF

Refractive Index Control of Silicon Oxynitride Thick Films on Core Layer of Silica Optical Waveguide (실리카 광도파로의 Core층인 Silicon Oxynitride후박의 굴절률 제어)

  • 김용탁;조성민;윤석규;서용곤;임영민;윤대호
    • Journal of the Korean Ceramic Society
    • /
    • v.39 no.6
    • /
    • pp.594-597
    • /
    • 2002
  • Silicon Oxynitride(SiON) thick films on p-type silicon(100) wafers have obtained by using plasma-enhanced chemical vapor deposition from SiH$_4$ , N$_2$O and N$_2$. Prism coupler measurements show that the refractive indices of SiON layers range from 1.4620 to 1.5312. A high deposition power of 180 W leads to deposition rates of up to 5.92${\mu}$m/h. The influence of the deposition condition on the chemical composition was investigated using X-ray photoelectron spectroscopy. After deposition of the SiON thick films, the films were annealed at 1050$^{\circ}C$ in a nitrogen atmosphere for 2 h to remove absorption band near 1.5${\mu}$m.

The Dry Etching Properties of ZnO Thin Film in Cl2/BCl3/Ar Plasma

  • Woo, Jong-Chang;Kim, Chang-Il
    • Transactions on Electrical and Electronic Materials
    • /
    • v.11 no.3
    • /
    • pp.116-119
    • /
    • 2010
  • The etching characteristics of zinc oxide (ZnO) were investigated, including the etch rate and the selectivity of ZnO in a $Cl_2/BCl_3$/Ar plasma. It was found that the ZnO etch rate, the RF power, and the gas pressure showed non-monotonic behaviors with an increasing Cl2 fraction in the $Cl_2/BCl_3$/Ar plasma, a gas mixture of $Cl_2$(3 sccm)/$BCl_3$(16 sccm)/Ar (4 sccm) resulted in a maximum ZnO etch rate of 53 nm/min and a maximum etch selectivity of 0.89 for ZnO/$SiO_2$. We used atomic force microscopy to determine the roughness of the surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the plasmas. Due to the relatively low volatility of the by-products formed during etching with $Cl_2/BCl_3$/Ar plasma, ion bombardment and physical sputtering were required to obtain the high ZnO etch rate. The chemical states of the etched surfaces were investigated using X-ray photoelectron spectroscopy (XPS). This data suggested that the ZnO etch mechanism was due to ion enhanced chemical etching.