• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 추계학술대회
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• pp.713-716
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• 2013

전체 채널 길이는 같지만 드레인과 게이트사이의 진성영역 길이(Lin), 드레인 및 소스의 불순물 농도, 유전율, 유전체 두께가 다른 N-채널 Tunneling FET의 특성을 비교 분석하였다. 사용된 소자는 SOI 구조의 N-채널 Tunneling FET이다. 진성영역 길이는 30~70nm, 드레인 dose 농도는 $2{\times}10^{12}cm^{-2}{\sim}2{\times}10^{15}cm^{-2}$, 소스 dose 농도는 $1{\times}10^{14}cm^{-2}{\sim}3{\times}10^{15}cm^{-2}$, 유전율은 3.9~29이고, 유전체 두께는 3~9nm이다. 소자 성능 지수는 Subthreshold slope(S-slope), On/off 전류비, 누설전류이다. 시뮬레이션 결과 진성영역 길이가 길며 드레인 농도가 낮을수록 누설전류가 감소한 것을 알 수 있었다. S-slope은 소스의 불순물 농도와 유전율이 높으며 유전체 두께는 얇을수록 작은 것을 알 수 있었다. 누설전류와 S-slope을 고려하면 N-채널 TFET 소자 설계 시 진성영역 폭이 넓으며 드레인의 불순물 농도는 낮고, 소스 농도와 유전율이 높으며 유전체 두께는 얇게 하는 것이 바람직하다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 학술대회 및 기술세미나 논문집 디스플레이 광소자
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• pp.81-82
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• 2006

Doping is a well-known method for improving electroluminescent (EL) efficiency of organic light emitting diodes. In our study, doping with 2 materials simultaneously, we could achieve improved EL efficiency. The emission layer was tris-(8-hydroxyquinoline)aluminum, and the 2 dopants were N,N'-dimethyl-quinacridone (DMQA) and 10-(2-Benzothiazolyl)-2, 3, 6, 7-tetrahydro-1,1,7,7,-tetramethyl 1-1H, 5H, 11H-[1] benzopyrano [6,7,8-ij]quinolizin-11-one (C-545T). The EL intensity of co-doped device was nearly flat, it shows that co-doping technique could be a effective way to improve the EL efficiency. EL efficiency of Single-doped device based on DMQA and C-S45T were ~6.47Cd/A and ~7.45Cd/A, respectively. Co-doped device showed higher EL efficiency of ~8.30Cd/A.

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.403-406
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• 2000

The piezoelectric properties and the doping effect of N $b_2$ $O_{5}$ and Mn $O_2$for 0.95PbZ $r_{x}$ $Ti_{x}$ $O_3$+0.05Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$ compositions have been investigated. In the composition of 0.95PbZ $r_{0.54}$ $Ti_{0.46}$ $O_3$+0.05Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$the Values Of $k_{p}$ find and $\varepsilon$$_{33}$ $^{T}$ are maximized, but $Q_{m}$ Was minimized ( $k_{p}$ =0.51, $Q_{m}$ =1750). The grain size was suppressed and the uniformity of grain was improved with doping concentration of N $b_2$ $O_{5}$ for 0.95PbZ $r_{0.54}$ $Ti_{0.46}$ $O_3$+0.005Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$sample. The values of $k_{p}$ increased and the values of $Q_{m}$ slightly decreased when 0.5 wt% of N $b_2$ $O_{5}$ is doped. And the values of $k_{p}$ was the same formation of the N $b_2$ $O_{5}$ dopant when 0.5 wt% of M $n_2$ $O_{5}$ is doped. But the values of $Q_{m}$ was deeply decreased when 0.5 wt% of Mn $O_2$is doped. As a experiment results under high electric field driving, this piezoelectric ceramics are very stable. Conclusively, piezoelectric ceramic compsiton investigated at this paper is suitable for application to high power piezoelectric devices.. devices..ices.. devices..

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.148-149
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• 2012

This paper reports doping of carbon atoms in GaN layer, which based on dimethylhydrazine (DMHy) and growth temperature. It is well known that dislocations can act as non-radiative recombination center in light emitting diode (LED). Recently, many researchers have tried to reduce the dislocation density by using various techniques such as lateral epitaxial overgrowth (LEO) [1] and patterned sapphire substrate (PSS) [2], and etc. However, LEO and PSS techniques require additional complicated steps to make masks or patterns on the substrate. Some reports also showed insertion of carbon doped layer may have good effect on crystal quality of GaN layer [3]. Here we report the growth of GaN epitaxial layer by inserting carbon doped GaN layer into GaN epitaxial layer. GaN:C layer growth was performed in metal-organic chemical vapor deposition (MOCVD) reactor, and DMHy was used as a carbon doping source. We elucidated the role of DMHy in various GaN:C growth temperature. When growth temperature of GaN decreases, the concentration of carbon increases. Hence, we also checked the carbon concentration with DMHy depending on growth temperature. Carbon concentration of conventional GaN is $1.15{\times}1016$. Carbon concentration can be achieved up to $4.68{\times}1,018$. GaN epilayer quality measured by XRD rocking curve get better with GaN:C layer insertion. FWHM of (002) was decreased from 245 arcsec to 234 arcsec and FWHM of (102) decreased from 338 arcsec to 302 arcsec. By comparing the quality of GaN:C layer inserted GaN with conventional GaN, we confirmed that GaN:C interlayer can block dislocations.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.382.1-382.1
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• 2014

Graphene field-effect transistors (GFET) is one of candidates for future high speed electronic devices since graphene has unique electronic properties such as high Fermi velocity (vf=10^6 m/s) and carrier mobility ($15,000cm^2/V{\cdot}s$) [1]. Although the contact property between graphene and metals is a crucial element to design high performance electronic devices, it has not been clearly identified. Therefore, we need to understand characteristics of graphene/metal contact in the GFET. Recently, it is theoretically known that graphene on metal can be doped by presence of interface dipole layer induced by charge transfer [2]. It notes that doping type of graphene under metal is determined by difference of work function between graphene and metal. In this study, we present the GFET fabricated by contact metals having high work function (Pt, Ni) for p-doping and low work function (Ta, Cr) for n-doping. The results show that asymmetric conductance depends on work function of metal because the interfacial dipole is locally formed between metal electrodes and graphene. It induces p-n-p or n-p-n junction in the channel of the GFET when gate bias is applied. In addition, we confirm that charge transfer regions are differently affected by gate electric field along gate length.

• 한국응용과학기술학회지
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• 제29권3호
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• pp.466-472
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• 2012

가시광선에 감응하는 광촉매를 제조하기 위하여 $TiO_2$에 질소(N)를 도핑하여 $N-TiO_2$를 제조하였다. 제조한 광촉매의 결정성, 입자 형상 및 도핑 상태는 XRD, FE-SEM 및 XPS를 이용하여 조사하였다. 제조한 광촉매의 활성 평가는 메틸렌블루의 광분해로 조사하였다. 제조한 광촉매는 anatase type이었으며, pH가 높을수록 결정화도가 향상되었다. 제조한 광촉매의 입자 크기는 pH 2.0에서 5.42 nm, pH 4.7에서 5.99 nm, pH 9.0에서 7.58 nm로, 입자 크기는 pH가 증가 할수록 약간씩 증가하였다. 광촉매의 활성은 결정화도에 비례하였다. $TiO_2$에 N를 도핑하여 제조한 $N-TiO_2$가 가시광선 하에서도 활성을 나타냈다. $TiO_2$에 도핑한 N는 격자 속에 존재하는 것이 아니라 표면에 존재하였다.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2005년도 춘계 학술대회
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• pp.173-179
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• 2005

본 연구에서는 Nickel-Metal Induced Lateral crystallization(Ni-MILC)에 depart에 따른 영향을 관찰함에 있어 Nickel에 Palladium Metal을 인접시켜(Pd assisted Ni-MILC) 그 결정화 속도를 향상시키는 방법을 제안하였다. a-Si에 Phosphorous가 doping 되어 있는 경우 Ni-MILC의 성장은 intrinsic에 비해 2.5배 감소되는 반면, Boron을 doping한 경우 Ni-MILC의 성장은 intrinsic의 경우보다 5배 이상의 성장을 보이게 되는데, well type의 Pd을 인접시킨 경우 Pd에 의해 유도된 tensile stress가 각 doping에 따른 성장 속도를 더욱 증대시키는 것을 확인할 수 있었으며, 이와 같은 현상을 MILC mechanism으로 설명하였다. 이는 Ni-MILC를 이용하여 다결정 실리콘 TFT 제작 시 결정화 속도로 인하여 문제가 되었던 N-type에서의 적용이 가능함과 동시에 contact MILC 등의 방법에도 이용가능성을 의미한다.

• 한국전기전자재료학회논문지
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• 제22권3호
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• pp.235-238
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• 2009

This paper describes the mechanical properties of poly (Polycrystalline) 3C-SiC thin films with $N_2$ in-situ doping. In this work, the poly 3C-SiC film was deposited by APCVD (Atmospheric Pressure Chemical Vapor Deposition) method using single-precursor HMDS (Hexamethyildisilane: $Si_2(CH_3)_6)$ at $1200^{\circ}C$. The mechanical properties of doped poly 3C-SiC thin films were measured by nono-indentation according to the various $N_2$ flow rate. In the case of 0 sccm $N_2$ flow rate, Young's Modulus and hardness were obtained as 285 GPa and 35 GPa, respectively. Young's Modulus and hardness were decreased according to increase of $N_2$ flow rate. The crystallinity and surface roughness was also measured by XRD (X-Ray Diffraction) and AFM (Atomic Force Microscopy), respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1401-1403
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• 2005

We present that the carrier balance can be improved by doping a hole transport layer of 4,4'- bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (${\alpha}$-NPD) with a hole blocking material of 2,9-dimethyl- 4,7-diphenyl-1,10-phenanthroline (BCP). The doping leads to disturb hole transport, which can enhance the balance of electron s and holes concentration in the emitting layer, aluminum tris(8 -hydroxyquinoline) (Alq3), resulting in enhanced electroluminescence (EL) quantum efficiency for the device with the doped ${\alpha}$-NPD.