• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.310-313
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• 2005

CW laser dopant activation (CLDA) is suggested as an alternative to conventional thermal annealing. The sheet resistance of the ion doped poly-Si after CLDA is sufficiently low compared to the value measured after thermal annealing. The surface damage due to ion doping on the poly-Si can be recovered while CW laser scan for dopant activation. Therefore, the CLDA can be applied to LTPS processing.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.218-221
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• 2004

The electronic state of ZnO doped with Al, Ga and In, which belong to III family elements in periodic table, was calculated using the density functional theory. In this study, the program used for the calculation on theoretical structures of ZnO and doped ZnO was Vienna Ab-initio Simulation Package (VASP), which is a sort of pseudo potential method. The detail of electronic structure was obtained by the describe variational $X{\alpha}(DV-X{\alpha})$(DV-Xa) method, which is a sort of molecular orbital full potential method. The optimized crystal structures obtained by calculations were compared to the measured structure. The density of state and energy levels of dopant elements was shown and discussed in association with properties.

• 한국전기전자재료학회논문지
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• 제18권7호
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• pp.589-593
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• 2005

The electronic states of ZnO doped with Al, Ga and In, which belong to III family elements in periodic table, were calculated using the density functional theory. In this study, the calculation was performed by two Programs; the discrete variational Xa (DV-Xa) method, which is a sort of molecular orbital full potential method; Vienna Ab-initio Simulation Package (VASP), which is a sort of pseudo potential method. The fundamental mixed orbital structure in each energy level near the Fermi level was investigated with simple model using DV-Xa. The optimized crystal structures calculated by VASP were compared to the measured structures. The density of state and the energy levels of dopant elements were shown and discussed in association with properties.

• Journal of Electrochemical Science and Technology
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• 제11권4호
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• pp.352-360
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• 2020

Lithium cobalt oxide (LiCoO₂, LCO) has been widely used as a cathode material for Li-ion batteries (LIBs) owing to its excellent electrochemical performance and highly reproducible synthesis even with mass production. To improve the energy density of the LIBs for their deployment in electro-mobility, the full capacity and voltage of the cathode materials need to exploited, especially by operating them at a higher voltage. Herein, we doped LCO with divalent calcium-ion (Ca²⁺) to stabilize its layered structure during the batteries' operation. The Ca-doped LCO was synthesized by two different routes, namely solid-state and co-precipitation methods, which led to different average particle sizes and levels of dopant's homogeneity. Of these two, the solid-state synthesis resulted in smaller particles with a better homogeneity of the dopant, which led to better electrochemical performance, specifically when operated at a high voltage of 4.5 V. Electrochemical simulations based on a single particle model provided theoretical corroboration for the positive effects of the reduced particle size on the higher rate capability.

• 청정기술
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• 제21권1호
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• pp.12-21
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• 2015

전도성 고분자를 이용한 새로운 기능성 재료의 개발은 에너지, 환경, 나노 기술 분야 발전에 크게 기여할 것으로 기대를 모으고 있다. 최근에는 전도성 고분자에 기능성 도펀트(functional dopant)를 삽입하여 고성능화에 초점을 맞춘 연구들이 많이 수행되고 있다. 본 총설은 새로운 전도성 고분자 합성의 관점으로 쓰여진 다른 문헌들과 달리, 삽입되는 기능성 도펀트의 역할과 응용 분야를 중심으로 서술하였다. 대표적인 기능성 도펀트의 종류로는 산화환원 활성(redox-active) 분자, 카본나노물질, 바이오물질, 킬레이팅(Chelating) 분자 등이 있으며, 각각의 도펀트의 고유한 특징에 따라 베터리, 수처리용 분리막, 센서 등 다양한 분야에 활용될 수 있다. 본 총설에서는 각각의 기능성 도펀트가 첨가 되었을 때 장점과 응용 방향에 대해 살펴 보고, 전도성 고분자의 안정성 향상을 위한 방법과 고려해야 할 점들에 대하여 제안하고자 한다.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.392-397
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• 2017

알칼리 금속을 도핑한 $BaSi_2$의 p-type 특성에 대하여 이해하기 위하여 density functional theory(DFT) 방법을 바탕으로 하는 결함 계산을 진행하였다. 우선 $BaSi_2$의 Si, Ba vacancies에 대해 계산을 진행하여서 도핑을 하지 않았을 때의 특성에 대해 이해해 보았다. 다음으로 알칼리 금속을 도핑한 구조의 p-type 특성과 비교 분석을 진행하기 위해서 잘 알려진 p-type dopants인 Al, In, Ag을 치환형으로 도핑한 구조의 특성에 대해 분석해 보았다. 마지막으로 알칼리 금속을 도핑하였을 때의 p-type 특성에 대해 계산해 보았고, K을 도핑하였을 때 잘 알려진 p-type dopants보다 더 나은 p-type 특성을 가질 수 있음을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.578-580
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• 2003

PEDOT [poly(3,4-ethylenedioxythiophene)] powder soluble in common organic solvent were synthesized by oxidative polymerization of EDOT (3,4-ethylene dioxythiophene) monomer using functional dopant, DEHSNa [sodium di(2-ethylhexyl)sulfosuccinate]. Transparent electrodes were made by spin casting of PEDOT/organic solvents on substrates. The electrode showed the transmittance < 90% in visible region and the surface resistance of> ${\sim}10^3\;ohm/{\square}$, respectively.

• 폴리머
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• 제31권1호
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• pp.74-79
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• 2007

[ $PPy^+DBS^-$ ] 복합체는 유화중합에 의해 제조되었고 이때 iron(III) chloride($FeCl_3$)는 개시제로, dodecyl benzene sulfonic acid(DBSA)는 계면활성제 및 도판트로 사용되었다. Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)는 chlorosulfonic acid(CSA)를 사용하여 설폰화되었고 양극은 $PPy^+DBS^-$ 복합체, 도전제 그리고 바인더로 구성되며 이때 바인더로 PPO와 설폰화된 poly (2,6-dimethyl-1,4-phenylene oxide) (SPPO)를 사용하였다. $PPy^+DBS^-/SPPO$ 양극은 $PPy^+DBS^-/PPO$에 비해 약 50% 높은 충 방전 성능을 나타내었는데 이는 SPPO가 바인더뿐만 아니라 도판트로 작용했기 때문이다. 더욱이 바인더로 사용된 고분자의 설폰화는 전도성 고분자와의 coulombic attraction을 유발시켜 두 상간의 혼화성을 증가시켰을 뿐만 아니라 양극과 전해질 사이의 접촉면적을 증가시켜 전기화학적으로 우수한 성능을 나타나게 했다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.192.2-192.2
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• 2014

Among various dopant candidates, nitrogen (N) atoms are considered as the most effective dopants to improve the diverse properties of graphene. Unfortunately, recent experimental and theoretical studies have revealed that different N-doped graphene (NGR) conformations can result in both p- and n-type characters depending on the bonding nature of N atoms (substitutional, pyridinic, pyrrolic, and nitrilic). To overcome this obstacle in achieving reliable graphene doping, we have carried out density functional theory calculations and explored the feasibility of converting p-type NGRs into n-type by introducing additional dopant candidates atoms (B, C, O, F, Al, Si, P, S, and Cl). Evaluating the relative formation energies of various binary-doped NGRs and the change in their electronic structure, we conclude that B and P atoms are promising candidates to achieve robust n-type NGRs. The origin of such p- to n-type change is analyzed based on the crystal orbital Hamiltonian population analysis. Implications of our findings in the context of electronic and energy device applications will be also discussed.

• 한국재료학회지
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• 제17권12호
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• pp.637-641
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• 2007

The total energy and strength of Mg alloy doped with Al, Ca and Zn, were calculated using the density functional theory. The calculations was performed by two programs; the discrete variational $X{\alpha}\;(DV-X{\alpha})$ method, which is a sort of molecular orbital full potential method; Vienna Ab-initio Simulation Package (VASP), which is a sort of pseudo potential method. The fundamental mixed orbital structure in each energy level near the Fermi level was investigated with simple model using $DV-X{\alpha}$. The optimized crystal structures calculated by VASP were compared to the measured structure. The density of state and the energy levels of dopant elements was discussed in association with properties. When the lattice parameter obtained from this study was compared, it was slightly different from the theoretical value but it was similar to Mk, and we obtained the reliability of data. A parameter Mk obtained by the $DV-X{\alpha}$ method was proportional to electronegativity and inversely proportional to ionic radii. We can predict the mechanical properties because $\Delta{\overline{Mk}}$is proportional to hardness.