• 전기학회논문지
• /
• 제65권10호
• /
• pp.1694-1696
• /
• 2016

Present thin film solar cells with hydrogenated amorphous silicon oxide (a-SiO:H) as an absorber suffer from low fill factor(FF) of 61~64 [%] in spite of its benefits related to high open circuit voltage ($V_{oc}$). Since degraded quality of a-SiO:H absorber by alloying with oxygen can affect the FF, we aimed to achieve high photosensitivity by minimizing $CO_2$ gas addition. Improving optical gap($E_{opt}$) has been attained by strong hydrogen dilution combined with lowering substrate temperature down to 100 [$^{\circ}C$]. Small amount of the $CO_2$ was added in order to disturb microcrystalline formation by high hydrogen dilution. The developed a-SiO:H has high photosensitivity (${\sim}2{\times}10^5$) and high $E_{opt}$ of 1.85 [eV], which contributed to attain remarkable FF of 74 [%] and high $V_{oc}$ (>1 [V]). As a result, high power conversion efficiency of 7.18 [%] was demonstrated by using very thin absorber layer of only 100 [nm], even though we processed all experiment at extremely low temperature of 100 [$^{\circ}C$].

• 대한수학회지
• /
• 제45권5호
• /
• pp.1203-1220
• /
• 2008

Let V be an arbitrary system of weights on an open connected subset G of ${\mathbb{C}}^N(N{\geq}1)$ and let B (E) be the Banach algebra of all bounded linear operators on a Banach space E. Let $HV_b$ (G, E) and $HV_0$ (G, E) be the weighted locally convex spaces of vector-valued analytic functions. In this paper, we characterize self-analytic mappings ${\phi}:G{\rightarrow}G$ and operator-valued analytic mappings ${\Psi}:G{\rightarrow}B(E)$ which generate weighted composition operators and invertible weighted composition operators on the spaces $HV_b$ (G, E) and $HV_0$ (G, E) for different systems of weights V on G. Also, we obtained compact weighted composition operators on these spaces for some nice classes of weights.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제3권3호
• /
• pp.145-152
• /
• 2003

Electrical gate and drain characteristics of double heterostructure InAlAs/InGaAs pseudomorphic HEMTs have been investigated under sub-bandgap photonic excitation ($hv). Drain $(V_{DS})-,{\;}gate($V_{DS})-$, and optical power($P_{opt}$)-dependent variation of the abnormal gate leakage current and associated physical mechanisms in the PHEMTs have been characterized. Peak gate voltage ($V_{GS,P}$) and the onset voltage for the impact ionization ($V_{GS.II}$) have been extracted and empirical model for their dependence on the $V_{DS}$ and $P_{opt} have been proposed. Anomalous gate and drain current, both under dark and under sub-bandgap photonic excitation, have been modeled as a parallel connection of high performance PHEMT with a poor satellite FET as a parasitic channel. Sub-bandgap photonic characterization, as a function of the optical power with $h\nu=0.799eV$, has been comparatively combined with those under dark condition for characterizing the bell-shaped negative humps in the gate current and subthreshold drain leakage under a large drain bias.

• 한국환경보건학회지
• /
• 제21권1호
• /
• pp.39-46
• /
• 1995

This study was carried out to investigate antibacterial activities of the green tea extract according to storage temperature as death velocity constant. The survey data were collected from seven green teas (2 Korean, 2 Japanese, 2 Chinease and 1 Vietnamese) and experimental strains were used E. coli No. 11234, Ent. aerogenes No. 11783, Ps. fiu. orescens No. 11210, S. marscens No. 11808, St. mutans No. 11823 and V. parahaernolyticus No. 11965. The experimental results obtained were as follows: 1. Antibacterial activities of the green tea extracts according to the strains were strikingly difference. That is, those of the samples appeared to be conspicuous on [St. mutans No. 11823 (Range of death velocity constant a day after, at 20$\circ$C 4.85~5.22) and V. parahaemolyticus No. 11965 (4.70~6.00) while E. coli No. 11234 (0.59~-0.30) and Ent. aerogenes No. 11783 (0.24~-0.11)] were not so. 2. To storage temperature at 5$\circ$C than that at 20$\circ$C, antibacterial activities of the green tea extract on Ps. fluorescens No. 11210, S. marscens No. 11808, E. coli No. 11234, and Ent. aerogenes No. 11783 were sensitived but St. mutans No. 11823 and V. parahaemolyticus No. 11965 were not related to those. 3. Antibacterial activities to the strains were increased within two days.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
• /
• pp.41-45
• /
• 2003

Impurities transmuted in GaN thin film and GaN nanowires after neutron irradiation are studied in this work. The structural properties of GaN nanowires were shown using by Transmission Electron Microscope(TEM). Transmuted impurities that are expected to be doped into GaN thin film and GaN nanowires are then confirmed by photoluminescence(PL). Transmuted atom in GaN materials is Ge atom, Ge-related peaks in GaN thin film lead to emit at 2.9eV, 2.25eV. But emission bands at 2.9eV, 2.25eV are not shown in PL spectra of GaN nanowires. Our experimental results are expected to give deep impact on nano-material doping technology for the achievement of the fabrication of nano-devices.

• 한국결정성장학회지
• /
• 제9권3호
• /
• pp.315-319
• /
• 1999

고상반응법으로 Eu와 Dy을 공부활제로 한$SrAl_2O_4$ 형광체 분말을 합성한 후, PL(Photoluminescence) 측정 장치를 이용하여 장잔광 축광재료소서 가장 중요한 발광특성과 장잔광특성을 조사하였다. 10K의 발광스펙트럼은 청색파장의 450nm(2.755 eV)와 녹색 파장의 520nm(2.384 eV)의 위치에서 뚜렷한 발광피크를 나타내었는데 반하여 300K에서는 450nm의 발광피크는 관측되지 않고 주로 520nm의 발광피크가 관측되었다. 그리고$SrAl_2O_4$:$Eu^{+2},Dy^{+3}$ 형광체의 잔광세기는 시간에 따라 지수 함수적으로 감소되나 발광의 감쇠속도가 작은 뛰어난 장잔광 특성을 나타내었다.

• 한국세라믹학회지
• /
• 제40권3호
• /
• pp.213-218
• /
• 2003

Band gap energies of SrTiO$_3$(STO) thin film on glass substrates were studied in terms of annealing temperature. The STO thin film was fabricated by our newly developed method based on the combination of the Self-Assembled Monolayer(SAM) technique and the Liquid Phase Deposition(LPD) method. The as-deposited film demonstrated a direct band gap energy of about 3.65 eV, which further increased to 3.73 eV and 3.78 eV by annealing at 40$0^{\circ}C$ and 50$0^{\circ}C$, respectively. The band gap energy saturated at about 3.70 eV for the crystallized film which was obtained by annealing at 600-$700^{\circ}C$. The relatively large band gap energies of our crystallized films were due to the presence of minor amorphous phase, grain boundaries and oxygen vacancies generated by annealing in air.

• 한국세라믹학회지
• /
• 제41권11호
• /
• pp.858-863
• /
• 2004

본 연구는 입방정 L $a_{2}$ 3/Ti $O_{2.84}$ 세라믹스의 전기전도율, 열기전력 그리고 자기적 특성에 대하여 조사하였다. 350 K 이하의 은도영역에서의 입방정 L $a_{2}$ 3/Ti $O_{2.84}$ 세라믹스의 열기전력은 음으로 나타났다 열기전력은 온도의 증가와 더불어 선형적으로 증가하여 A+BT의 형태로 표현가능 하였으며, Emin과 Wood가 제안한 모델과 잘 일치하였다. 이와 같은 열기전력의 온도의존성은 L $a_{2}$ 3/Ti $O_{2.84}$ 세라믹스의 전도 carrier가 small polaron임을 의미한다. L $a_{2}$ 3/Ti $O_{2.84}$ 세라믹스는 실온 이하의 특정온도에서 variable range hopping에서 small polaron hopping으로 변화하였다. 저온영역에서는 직류전도 기구해석은 Mott의 접근방식을 이용하였다. Mott의 보조변수 해석결과 Fermi면에서의 상태밀도 [N( $E_{F}$)]는 3.18${\times}$$10^{20}$ $cm^{-3}$e $V^{-1}$이었으며, 무질서에너지 $W_{d}$는 0.93로 고온에서의 활성화 에너지 보다 매우 크다. 200K와 300K온도 범위에서 log($\sigma$T)와 1/T의 직선 관계가 존재 하였으며, small polaron의 hopping energy는 0.15 eV였다.

• 정보처리학회논문지B
• /
• 제15B권6호
• /
• pp.609-612
• /
• 2008

G = (V, E) 를 단순 무방향성 그래프라 하자. Minimum Vertex Cover (MVC) 문제는 C 를 V 의 부분 집합이라 할 때 모든 간선들이 C 내의 최소 한 개 정점과 인접하게 되는 최소 집합 C 를 계산하는 것이다. 다른 많은 그래프 이론 문제와 마찬가지로 본 문제도 NP-hard 문제임이 증명되었다. 본 논문에서는 MVC 문제를 위한 LeafGA 라는 새로운 유전 알고리즘을 제시하며 또한 제시된 알고리즘을 널리 알려 진 기준 그래프들에 적용함으로써 그 효용성을 보인다.

• E2M - 전기 전자와 첨단 소재
• /
• 제7권5호
• /
• pp.389-396
• /
• 1994

The bilayer film of Ag/a-S $e_{75.G}$ $e_{25}$ and the monolayer film of a-S $e_{75.G}$ $e_{25}$ act as a negative-type and a positive-type resist in focused ion beam lithography, respectively. Using a model which takes into account the ion stopping power, the ion projected range, the ion concentration implanted into resists and the ion transmission coefficient, etc., the ion resist parameters are calculated for a broad range of ion energies and implanted doses. Ion sources of A $r^{+}$, S $i^{++}$ and G $a^{+}$ are used to expose resists. As the calculated results, the energy loss per unit distance by Ga'$^{+}$ ion is about 10$^{3}$[keV/.mu.M] and nearly constant for all energy range. Especially, the projected range and struggling for 80[keV] G $a^{+}$ ion energy are 0.0425[.mu.m] and 0.020[.mu.m], , respectively and the resist thickness of a-S $e_{75}$ G $e_{25}$ to minimize the ion penetration rate into a substrate is 0.118[.mu.m].u.m]..u.m].