• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.43-47
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• 2012

Electromigration in molten $Ge_2Sb_2Te_5$ (GST) was characterized using pulsed DC stress to an isolated line structure. When an electrical pulse was applied to the GST, GST lines were melted by Joule heating, and Ge and Sb atoms migrate to the cathode, whereas Te atoms migrate to the anode. This elemental separation in the molten GST was caused by an electrostatic force-induced electromigration. The effects of O-, N-, and Bi-doping on the electromigration were also investigated, and atomic mobility changes by the doping were investigated by quantifying $DZ^*$ values. The Bi -doping did not affect the $DZ^*$ values of the constituent atoms in the molten GST, but the D$DZ^*$ values decreased by O-doping and N-doping.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.483-486
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• 2010

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.194-194
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• 2009

3C-SiC thin films are widely used in extreme environments, radio frequency (RF) environments, and bio-materials for micro/nano electronic mechanical systems (M/NEMS). The mechanical properties of 3C-SiC thin films need to be considered when designing M/NEMS, so Young's Modulus and the hardness need to be accurately measured. Young's Modulus and the hardness are influenced by N-doping. In this paper, we show that the mechanical properties of poly (polycrystalline) 3C-SiC thin films are influenced by the N-doping concentration. Furthermore, we measure the mechanical properties of 3C-SiC thin films for N-doping concentrations of 1%, 3%, and 5%, by using nanoindentation. For films deposited using a 1% N-doping concentration, Young's Modulus and the hardness were measured as 270 GPa and 30 GPa, respectively. When the surface roughness of the thin films was investigated by using atomic force microscopy (AFM), the roughness of the 5% N-doped 3C-SiC thin film was the lowest of all the films, at 15 nm.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.3-5
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• 2002

Breakdown characteristics of a punch-through diode with n+p+p-n+ structure are analyzed with two-dimensional device simulation. Effects of base doping concentration and profile on the breakdown are presented. An analytical expression of a maximum base doping level for the punch-through breakdown is derived. The diode with a linearly graded base doping shows superior leakage current and capacitance is satisfactory for applications for low-voltage circuits.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.10
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• pp.642-647
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• 2014

For feasible study of opto-electrical application regarding to oxide semiconductor, we implemented the N doped ZnO growth using a atomic layer deposition technique. The p-type ZnO deposition, necessary for ZnO-based optoelectronics, has considered to be very difficulty due to sufficiently deep acceptor location and self-compensating process on doping. Various sources of N such as $N_2$, $NH_3$, NO, and $NO_2$ and deposition techniques have been used to fabricate p-type ZnO. Hall measurement showed that p-type ZnO was prepared in condition with low deposition temperature and dopant concentration. From the evaluation of photoluminescence spectroscopy, we could observe defect formation formed by N dopant. In this paper, we exhibited the electrical and optical properties of N-doped ZnO thin films grown by atomic layer deposition with $NH_3OH$ doping source.

• Macromolecular Research
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• v.15 no.1
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• pp.5-9
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• 2007

The attenuated total reflection infrared (ATR-IR) spectra of trans-polyacetylene (trans-PA) film doped with sodium (n-doping) were observed in the range of 1900 to $700cm^{-1}$. The observed IR bands were attributed to negatively charged domains created by n-doping electrons. The doping-induced IR bands showed considerable difference from its pristine film. After doping, the out-of-plane CH deformation band of the strong $1010cm^{-1}$ region in the pristine film disappeared while several new bands were observed at 1600 (due to C=C stretching), 1400 (due to in-plane CH bending), 1290 and 1174 (due to CH stretching), and $880cm^{-1}$ (due to CC stretching) regions for Na-doped PA. In particular, a weak band of C=C stretching at $1600cm^{-1}$ was newly obtained for the first time in the present study. The electro conductivity of the doped trans-PA film was $10^2S/cm$ and the origins of doping-induced IR bands are discussed in terms of solitons and polarons.

• Journal of the Korean Ceramic Society
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• v.56 no.4
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• pp.374-386
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• 2019

A process for nitrogen doping of TiO₂ ceramics was developed, whereby polycrystalline titania particles were prepared at 450-1000℃ with variation of the firing schedule under N₂ atmosphere. The effect of nitrogen doping on the polycrystallites was investigated by X-ray diffraction (XRD) and Raman analysis. The microstructure of the TiO₂ ceramics changed with variation of the firing temperature and the firing atmosphere (N₂ or O₂). The microstructural changes in the nitrogen-doped TiO₂ ceramics were closely related to changes in the Raman spectra. Within the evaluated temperature range, the nitrogen-doped titania ceramics comprised anatase and/or rutile phases, similar to those of titania ceramics fired in air. Infiltration of nitrogen gas into the titania ceramics was analyzed by Raman spectroscopy and XRD analysis, showing a considerable change in the profiles of the N₂-doped TiO₂ ceramics compared with those of the TiO₂ ceramics fired under O₂ atmosphere. The nitrogen doping in the anatase phase may produce active sites for photocatalysis in the visible and ultraviolet regions.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.180.2-180.2
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• 2014

Opening a bandgap by forming graphene nanoribbons (GNRs) and tailoring their properties via doping is a promising direction to achieve graphene-based advanced electronic devices. Applying a first-principles computational approach combining density functional theory (DFT) and DFT-based non-equilibrium Green's function (NEGF) calculation, we herein study the structural, electronic, and charge transport properties of boron-nitrogen binary edge doped GNRs and show that it can achieve novel doping effects that are absent for the single B or N doping. For the armchair GNRs, we find that the B-N edge co-doping almost perfectly recovers the conductance of pristine GNRs. For the zigzag GNRs, it is found to support spatially and energetically spin-polarized currents in the absence of magnetic electrodes or external gate fields: The spin-up (spin-down) currents along the B-N undoped edge and in the valence (conduction) band edge region. This may lead to a novel scheme of graphene band engineering and benefit the design of graphene-based spintronic devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.368-369
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• 2008

This paper describes the mechanical properties of poly(polycrystalline) 3C-SiC thin film with various doping concentration, in which poly 3C-SiC thin film's mechanical properties according to the n-doping concentration 1%$(9.2\times10^{15}cm^{-3})$, 3%$(5.2\times10^{17}cm^{-3})$, and 5%$(6.8\times10^{17}cm^{-3})$ respectively was measured by nano indentation. In the case of $9.2\times10^{15}^{-3}$ n-doping concentration, Young's Modulus and hardness were obtained as 270 GPa and 30 GPa, respectively. When the surface roughness according to n-doping concentrations was investigated by AFM(atomic force microscope), the roughness of poly 3C-SiC thin film doped by 5% concentration was 15 nm, which is also the best of them.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.33-38
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• 2000

The ~1540 nm Er$^{3+}$ photoluminescence (PL) and photoluminescence excitation (PLE) spectra of Er-implanted Mg-codoped GaN (GaN:Er+Mg) exhibit that the excitation efficiency of a specific Er$^{3+}$ center among different Er$^{3+}$ centers existing in Er-implanted GaN is selectively enhanced, compared to Er-implanted undoped GaN (GaN:Er). In GaN:Er+Mg, the 1540 nm PL peaks characteristic of the so-called "violet-pumped" Er$^{3+}$ center and the ~2.8-3.4 eV (violet) PLE band are significantly strengthened by the Mg-doping. The intra-f absorption PLE bands associated with this "violet-pumped" center are also enhanced by this doping. The 1540 nm PL peaks originating from the violet-pumped center dominate the above-gap-excited Er$^{3+}$ PL spectrum of GaN:Er+Mg, whereas it was unobservable under above-gap excitation in GaN:Er. All of these results indicate that Mg doping increases the efficiency of trap-mediated excitation of Er$^{3+}$ emission in Er-implanted GaN.planted GaN.