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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Vacuum Society
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Journal DOI :
The Korean Vacuum Society
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Volume & Issues
Volume 15, Issue 6 - Nov 2006
Volume 15, Issue 5 - Sep 2006
Volume 15, Issue 4 - Jul 2006
Volume 15, Issue 3 - May 2006
Volume 15, Issue 2 - Mar 2006
Volume 15, Issue 1 - Jan 2006
Selecting the target year
Atmospheric Plasma and Its Applications
Uhm Han-Sup ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 117~138
Plasmas can be made by electrical discharge on earth. Most of the plasmas on earth have been generated in low pressure environments where the pressure is less than one millionth of the atmospheric pressure. However, there are many plasma applications which require high pressure plasmas. Therefore, scientists start research on plasma generation at high pressure to avoid use of expensive vacuum equipments. Large-volume inexpensive plasmas are needed in the areas of material processing, environmental protection and improvement, efficient energy source and applications, etc. We therefore developed new methods of plasma generations at high pressure and carried out research of applying these plasmas to high tech industries representing 21 century. These research fields will play pivotal roles in material, environmental and energy science and technology in future.
Adsorption of H Atoms on the Si(111)
Yu Sang-Yong ; Lee Geun-Seop ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 139~144
Using scanning tunneling microscopy (STM) measurements, we studied the adsorption of hydrogen on the Si(111)
-In surface at room temperature. The H atom features are found to be located between the two protrusions in one side of the
chain. The adsorbed H preferentially occupies one of the two zigzag In subchains, suggesting that the adsorption of H is influenced by the subsurface structure. The adsorbed H atom induces not only a localized distortion but also perturbs the distant region and results in a period-doubling modulations in the STM images. This H-induced perturbation differs from the Na-Induced perturbation on the same surface.
STM Study of Self Assembled Monolayer Formed from Binary Mixtures of Substituted Alkyl Chains
Son S.B. ; Lee H. ; Jeon I.C. ; Hahn J.R. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 145~151
The molecular assembly of p-iodo-phenyl octadecyl ether (I-POE), p-iodo-phenyl docosyl ether (I-PDE) and a binary mixture of these two molecules on graphite has been studied using a scanning tunneling microscope. Each molecular system self-assembles on the graphite surface to form a stable monolayer with a head-to-tail configuration. For the binary system, the I-POE and I-PDE molecules do not mix on the surface, preferring instead to form isolated monolayer domains. Here, the I-POE molecules are preferentially adsorbed on the graphite surface, due to the effects of alkyl chain length and the functional group on the monolayer structure.
Reconstruction Change of Si(5 5 12) Induced by Selective Bi Adsorption
Cho Sang-Hee ; Seo Jae-M. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 152~161
In order to test the capacity of Si(5 5 12) as a potential template for nanowire fabrication, Bi/Si(5 5 12) system has been studied by STM. With Bi deposition, Si(5 5 12) has been transformed to Si(3 3 7) terrace. Initially Bi atoms selectively replace Si-dimers and Si-adatoms with Bi-dimers and Bi-adatoms, respectively. With extended Bi adsorption, Bi-dimers adsorb on the pre-adsorbed Bi-dimers and Bi-atoms. These dimers in the second layer form Bi-dimer pairs having relatively stable
bonding, Finally, the Bi-dimer adsorbs on the Bi-dimers in the second layer and saturates. It can be deduced that both surface transformation to (3 3 7) and site-selective Bi adsorption are possible due to substrate-strain relaxation through inserting Bi atoms into subsurface of Si substrate.
Symmetry of GaAsN Conduction-band Minimum: Resonant Raman Scattering Study
Seong M.J. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 162~167
The symmetry of the conduction-band minimum of
is probed by performing resonant Raman scattering (RRS) on thin layers of
epitaxially grown on Ge substrates. Strong resonance enhancement of the LO(longitudinal optical)-phonon Raman intensity is observed with excitation energies near the
as well as
transitions, However, in contrast to the distinct LO-phonon line-width resonance enhancement and activation of various X and L zone-boundary phonons brought about slightly below and near the
transition, respectively, we have not observed any resonant LO-phonon line-width broadening or activation of sharp zone-boundary phonons near the
transition. The observed RRS results reveal that the conduction-band minimum of GaAsN predominantly consists of the delocalized GaAs bulk-like states of
Temperature-dependent Characteristics of Nucleation Layers for GaN Nanorods
Lee Sang-Hwa ; Choe Hyeok-Min ; Kim Chin-Kyo ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 168~172
GaN nucleation layers were grown by hydride vapor phase epitaxy (HVPE) and the effect of growth temperature on the structural properties of GaN nucleation layers for nanorods was investigated by synchrotron x-ray scattering and Atomic Force Microscopy (AFM). For the samples grown at different temperatures, two-component rocking profiles of (002) GaN Bragg peaks for the GaN nucleation layers were observed with one very sharp and the other broad. It was shown that the two-component rocking profile could be qualitatively explained by surface morphology, which was in good agreement with AFM result, from which we could conclude that relatively low temperature is favorable for GaN nanorods formation.
Properties of Ferroelectric Materials Applicable to Nano-storage Media
Choi J.S. ; Kim J.S. ; Hwang I.R. ; Byun I.S. ; Kim S.H. ; Jeon S.H. ; Lee J.H. ; Hong S.H. ; Park B.H. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 173~179
We have investigated structural and electrical properties of
(PZT) thin films deposited by pulsed laser deposition methods. PZT thin films have been deposited on
(LMO) bottom electrodes with
(LAO) substrates during different deposition times. High-resolution x-ray diffraction data have shown that all the PZT films and bottom electrodes are highly oriented. The thickness of each film is determined by field-emission scanning electron microscope. We have also observed root mean square roughness by using atomic force microscopy mode, and local polarization distribution and retention behavior of a ferroelectric domain by using piezoelectric force microscopy mode. A PZT/LMO structure has shown good ferroelectric and retention properties as the media for nano-storage devices.
Fabrication and Performance of
Thin Film Thermoelectric Generators
Kim Il-Ho ; Jang Kyung-Wook ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 180~185
Microwatt power level at relatively high voltage(order of volt) was produced by
thin film thermoelectric generators, and maximum output power varied with temperature difference in the square-law relation. Output voltage and current were possible to control by changing the way of electrical connection as well as the number of stacking plate-modules. Variation of open circuit voltage and short circuit current with temperature difference showed a linear relationship. There were, however, some differences in variations; open circuit voltage were dependent on the number of plate-module when connected in series, but it was not for parallel connection. On the other hand, short circuit current showed the opposite behavior to the case of open circuit current.
Study on InGaAs/InGaAsP/InP Quantum-dot Molecules for Quantum Interference devices
Kim Jin-Soak ; Kim Eun-Kyu ; Jeong Weon-G. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 186~193
In this study, we analyzed the electrical and optical properties of metalorganic chemical vapor deposition grown InGaAs/InGaAsP/InP quantum dot(QD) molecules by using photoluminescence and deep-level transient spectroscopy. From these resulte, the energy levels of the large QDs are located at deeper region from the conduction band edge of the barrier than that of the small QDs, The large QDs seem to have the energy states more than two, and these energy levels of the QD molecules are located at 0.35, 0.42, and 0.45 eV from conduction band edge under -4 V reverse bias conditions. The energy levels are closely coupled under low reverse bias, and then decoupled as the bias voltage is increased.
Structural and Optical Properties of Self-assembled InAs/InAl(Ga)Ae Quantum Dots on InP
Kim Jin-Soo ; Lee Jin-Hong ; Hong Sung-Ui ; Kwack Ho-Sang ; Choi Byung-Seok ; Oh Dae-Kon ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 194~200
Self-assembled InAs/InAl(Ga)As quantum dots (QDs) were grown on InP substrates by a molecular-beam epiaxy, and their structural and optical properties were investigated by atomic force microscopy (AFM), transmission electron microscopy (TEM), and room-temperature photoluminescence (PL). AFM images indicated that the InAs quantum structures showed various shapes such as quantum dashes, asymmetric and symmetric QDs mainly caused by the initial surface conditions of InAl(Ga)As with the intrinsic phase separation. For the buried InAs QDs in an InAlGaAs matrix, the average lateral size and height of QDs were 23 and 2 nm, respectively. By changing the growth conditions for the QD samples, the emission wavelength of
was obtained, which is one of the wavelength windows for fiber optic communications.
Spatially-resolved Photoluminescence Studies on Intermixing Effect of InGaAs Quantum Dot Structures Formed by AlAs Wet Oxidation and Thermal Annealing
Hwang J.S. ; Kwon B.J. ; Kwack H.S. ; Choi J.W. ; Choi Y.H. ; Cho N.K. ; Cheon H.S. ; Cho W.C. ; Song J.D. ; Choi W.J. ; Lee J.I. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 201~208
Optical characteristics of InGaAs quantum dot (QD) laser structures with an Al native oxide (AlOx) layer as a current-blocking layer were studied by means of photoluminescence (PL), PL excitation, and spatially-resolved micro-PL techniques. The InGaAs QD samples were first grown by molecular-beam epitaxy (MBE), and then prepared by wet oxidation and thermal annealing techniques. For the InGaAs QD structures treated by the wet oxidation and thermal annealing processes, a broad PL emission due to the intermixing effect of the AlOx layer was observed at PL emission energy higher than that of the non-intermixed region. We observed a dominant InGaAs QD emission at about 1.1 eV in the non-oxide AlAs region, while InGaAs QD-related emissions at about 1.16 eV and
were observed for the AlOx and the SiNx regions, respectively. We conclude that the intermixing effect of the InGaAs QD region under an AlOx layer is stronger than that of the InGaAs QD region under a non-oxided AlAs layer.
Optical Characteristic of InAs Quantum Dots in an InGaAs/GaAs Well Structure
Nam H.D. ; Kwack H.S. ; Doynnette L. ; Song J.D. ; Choi W.J. ; Cho W.J. ; Lee J.I. ; Cho Y.H. ; Julien F.H. ; Choe J.W. ; Yang H.S. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 209~215
We investigated the optical property and the electronic subband structure of InAs quantum dots in an InAsGa/GaAs well structure utilizing photoluminescence (PL), PL excitation (PLE) and near infrared transmission spectroscopy. From transmission and PLE spectra, we found three bound states in the InAs quantum dot and two bound states in InGaAs/GaAs quantum well, and correlated to the results of intersubband transitions observed in photocurrent spectrum.
Electrical Property in InAn/GaAs Quantum Dot Infrared Photodetector with Hydrogen Plasma Treatment
Nam H.D. ; Song J.D. ; Choi W.J. ; Cho W.J. ; Lee J.I. ; Choe J.W. ; Yang H.S. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 216~222
In this paper, we investigated the effect of hydrogen-plasma (H-plasma) treatment on the electrical and optical properties of a quantum dot infrared photodetector (QDIP) with a 5-stacked InAs dots in an InGaAs/GaAs well structure and
SL (superlattice) current blocking layer. It has been observed that H-plasma treatment didn't affect the band structure of QDIP. It has been also observed that the H-plasma treatment on the QDIP not only enhance the electrical property of QDIP by curing the defect channels in
SL but also introduce defects in QDIP structure. The H-plasma treatment for 10 min with 20 W of RF power provided the lowest dark current, which made it possible to measure the photo-current (PC) of QDIP whose PC was not detectable without the H-plasma treatment due to the high dark current,
Anomalous Effect of Hydrogenation on the Optical Characterization
Quantum Dot Infrared Photodetectors
Lim J.Y. ; Song J.D. ; Choi W.J. ; Cho W.J. ; Lee J.I. ; Yang H.S. ;
Journal of the Korean Vacuum Society, volume 15, issue 2, 2006, Pages 223~230
We have investigated the characteristics of hydrogen (H) plasma treated quantum dot infrared photodetectors (QDIPs). The structure used in this study consists of 3 stacked, self assembled
QD layer separated by GaAs barrier layers that were grown by molecular beam epitaxy. Optical characteristics of QDIPs, such as photoluminescence (PL) spectra and photocurrent spectra, have been studied and compared with each other for the as grown and H plasma treated QDIPs. H plasma treatment, resulted in the splitting of PL peak, which can be attributed to the redistribution of the size of QDs. The activation energies estimated from the temperature dependence of integrated PL intensity for as grown and H plasma treated QDIPs are found to be in good agreement with those determined from corresponding peaks of photocurrent spectra. It is also noted that photocurrent is detected up to 130 K for the H plasma treated QDIP, suggesting the future possibility for the development of infrared photodetectors with high temperature operation.