• 한국결정성장학회지
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• 제15권6호
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• pp.252-259
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• 2005

[ $CuGaSe_2$ ] 단결정 박막은 수평 전기로에서 합성한 $CuGaSe_2$ 다결정을 증발원으로하여, hot wall epitaxy(HWE) 방법으로 증발원과 기판(반절연성 GaAs(100))의 온도를 각각 $610^{\circ}C,\;450^{\circ}C$로 고정하여 단결정 박막을 성장하였다. 이때 단결정 박막의 결정성은 광발광 스펙트럼(PL)과 이중결정 X-선 요동곡선 (DCRC)으로부터 구하였다. Hall 효과는 Van der Pauw 방법에 의해 측정되었으며, 293 K에서 운반자 농도와 이동도는 각각 $4.87{\times}10^{17}/cm^3,\;129cm^2/V{\cdot}s$였다. $n-Cds/p-CuGaSe_2$ 합 태양전지에 $80mW/cm^2$의 광을 조사시켜 최대 출력점에서 전압은 0.41 V, 전류밀도는 $21.8mA/cm^2$였고, fill factor는 0.75 그리고 태양전지 전력변환 효율은 11.17% 였다.

• 한국태양에너지학회 논문집
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• 제25권4호
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• pp.1-11
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• 2005

The stoichiometric mixture of evaporating materials for the $CuInSe_2$ single crystal thin film was prepared from horizontal furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal $CuInSe_2$, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were $5.783\;{\AA}$ and $11.621\;{\AA}$, respectively. To obtain the $CuInSe_2$ single crystal thin film, $CuInSe_2$ mixed crystal was deposited on throughly etched GaAs(100) by the HWE(Hot Wall Epitaxy) system. The source and substrate temperature were $620^{\circ}C$ and $410^{\circ}C$ respectively. The crystalline structure of $CuInSe_2$ single crystal thin film was investigated by the double crystal X-ray diffraction(DCXD). Hall effect on this sample was measured by the method of Van der Pauw and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by impurity scattering in the temperature range 30 K to 100 K and by lattice scattering in the temperature range 100 K to 293 K. The temperature dependence of the energy band gap of the $CuInSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=1.1851\;eV-(8.99{\times}10^{-4}\;eV/K)T^2/(T+153\;K)$. The open-circuit voltage, short current density, fill factor, and conversion efficiency of $n-CdS/p-CuGaSe_2$ heterojunction solar cells under $80\;mW/cm^2$ illumination were found to be 0.51V, $29.3\;mA/cm^2$, 0.76 and 14.3 %, respectively.

• 태양에너지
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• 제11권1호
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• pp.41-49
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• 1991

본 연구에서는 기판의 증착온도를 $200{\pm}5[5^{\circ}C]$로 유지하여 진공증착법으로 (P)SiC/(N)Si 태양전지를 제작하고 그의 특성을 조사하였다. SiC 박막의 최적 두께 $1.2[{\mu}m]$는 박막두께와 변환효율과의 관계로부터 정해졌고 태양전지의 특성은 열치리에 의하여 개선되었다. 최적조건의 열처리 온도와 시간은 $420[^{\circ}C]$에서 12분이고 분광응답의 피크값은 열처리 온도의 증가와 더블어 장파장 쪽으로 이동함을 알았다. X선 회절분석 및 SEM검사는 열처리 온도와 시간에 따라 SiC 박막내에서 결정성장을 보여주며 $2.5{\times}1[cm^2]$의 태양전지에서 최고 변환효율은 11.7[%]이다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.387.1-387.1
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• 2016

Transparent materials are necessary for most photoelectric devices, which allow the light generation from electric energy or vice versa. Metal oxides are usual materials for transparent conductors to have high optical transmittance with good electrical properties. Functional designs may apply in various applications, including solar cells, photodetectors, and transparent heaters. Nanoscale structures are effective to drive the incident light into light-absorbing semiconductor layer to improve solar cell performances. Recently, the new metal oxide materials have inaugurated functional device applications. Nickel oxide (NiO) is the strong p-type metal oxide and has been applied for all transparent metal oxide photodetector by combining with n-type ZnO. The abrupt p-NiO/n-ZnO heterojunction device has a high transmittance of 90% for visible light but absorbs almost entire UV wavelength light to show the record fastest photoresponse time of 24 ms. For other applications, NiO has been applied for solar cells and transparent heaters to induce the enhanced performances due to its optical and electrical benefits. We discuss the high possibility of metal oxides for current and future transparent electronic applications.

• 한국전기전자재료학회논문지
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• 제29권7호
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• pp.445-448
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• 2016

Transparent UV photodetector was achieved by using wide bandgap metal oxide materials. In order to realize transparent heterojunction UV photodetector, n-type ZnO and p-type NiO metal oxide materials were employed. High light-absorbing SnS layer was inserted into the n-ZnO and p-NiO layers. High-performing UV photodetector was realized by ZnO/SnS/NiO/ITO structures to provide extremely fast response times (Fall time: $7{\mu}s$ and rise time: $13{\mu}s$) and high rectifying ratio. The use of functional SnS-embedded photodetector would provide a route for high functional photoelectric devices.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.214-217
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• 2006

p-type 비정질 실리콘 에미터와 n-type 실리콘 기판의 계면에 intrinsic 비정질 실리콘을 증착함으로써 계면의 재결합을 억제하여 20%가 넘는 효율을 보이는 이종접합 태양전지가 Sanyo에 의해 처음 제시된 후 intrinsic layer에 대한 연구가 많이 진행되어 왔다. 하지만 p-type wafer의 경우는 n-type에 비해 intrinsic buffer의 효과가 미미하거나 오히려 특성을 저하시킨다는 보고가 있으며 그 이유로는 minority carrier에 대한 barrier가 상대적으로 낮다는 것과 partial epitaxy가 발생하기 때문으로 알려져 있다. 본 연구에서는 partial epitaxy를 억제하기 위한 방법으로 증착 온도를 낮추고 QSSPC를 사용하여 minority carrier lifetime을 측정함으로써 각 온도에 따른 passivation 특성을 평가하였다. 또한 SiH4에 H2를 섞어서 증착하였을 경우 각 dilution ratio(H2 flow/SiH4 flow)에서의 passivation 특성 또한 평가하였다. 기판 온도 $100^{\circ}C$에서 증착된 샘플의 lifetime이 가장 길었으며 그 이하와 이상에서는 lifetime이 감소하는 경향을 보였다 낮은 온도에서는 박막 자체의 결함이 증가하였기 때문이며 높은 온도에서는 partial epitaxy의 영향으로 추정된다. H2 dilution을 하여 증착한 샘플의 경우 SiH4만 가지고 증착한 샘플보다 훨씬 높은 lifetime을 가졌다 이 또한 박막 FT-IR결과로부터 H2 dilution을 한 경우 compact한 박막이 형성되는 것을 확인할 수 있었는데 radical mobility 증가에 의한 박막 특성 향상이 원인으로 생각된다.

• 한국재료학회지
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• 제9권12호
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• pp.1155-1159
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• 1999

플라즈마 화학증착 (PECVD) 장비를 이용하여 $SnO_2$ 투명전도막이 피막된 유리기판 위에 p-SiC/i-Si/n-Si 이종접합 태양전지를 제작하였다. p-SiC 층의 증착중에 기체조성 x=$CH_4/\;(SiH_4+CH_4)$의 변화에 대한 태양전지의 광기전 특성을 관찰하였다. 기체조성(x)이 0~0.4의 범위에서 p-SiC 창층의 광학적 밴드갭의 증가로 인하여 태양전지의 효율은 증가하였으나, 그 이상의 기체조성에서는 p-SiC/i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 i-Si 계면에서의 조성불일치가 증가하여 태양전지의 효율이 감소하였다. 이러한 계면문제는 p-SiC 층과 I-Si 층 사이에 I-SiC 완충층을 삽입함으로써 크게 감소하였다. 그 결과 유효면적이 $1cm^2$인 glass/$SnO_2$/p-SiC/i-SiC/i-Si/n-Si/Ag 구조의 박막 태양전지는 100mW/$cm^2$ 조도 하에서 8.6%의 효율을 나타내었다. ($V_{oc}$=0.85V, $J_{sc}$=16.42mA/$cm^2$, FF=0.615)

• 한국재료학회지
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• 제25권4호
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• pp.171-176
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• 2015

We present the detection characteristics of nitrogen monoxide(NO) gas using p-type copper oxide(CuO) thin film gas sensors. The CuO thin films were fabricated on glass substrates by a sol-gel spin coating method using copper acetate hydrate and diethanolamine as precursors. Structural characterizations revealed that we prepared the pure CuO thin films having a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the NO gas sensing measurements that the p-type CuO thin film gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as $100^{\circ}C$. Additionally, these CuO thin film gas sensors were found to show reversible and reliable electrical response to NO gas in a range of operating temperatures from $60^{\circ}C$ to $200^{\circ}C$. It is supposed from these results that the p-type oxide semiconductor CuO thin film could have significant potential for use in future gas sensors and other oxide electronics applications using oxide p-n heterojunction structures.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.234-234
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• 2003

Indium tin oxide(ITO) is an advanced ceramic material with many electronic and optical applications due to its high electrical conductivity and transparency to light ITO thin films are used in transparent electrodes for display devices, transparent coatings for solar energy heat mirrors and windows films in n-p heterojunction solar cells, etc. Almost all display devices were fabricated on transparent ITO electrode substrates. There are several factors that cause decay in the efficiency and the failure of display devices. The degradation or damage of ITO is one of the main factors. Under normal operating conditions, the electric fold required for the operation of display devices is very high As a high electric field induces the joule heat, the degradation of the ITO thin film may be expected. Therefore, it is worthy to investigate the thermal and electrical effect on ITO thin films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.11-11
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• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.