• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.160-162
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• 2009

We have prepared and characterized particle based CIGS thin films using a thermal evaporator. As the copper rate, selenium rate changed, CIGS particles were obtained at $240^{\circ}C$ for 6 hours from the reaction of $CuCl_2$, $InCl_3$, $GaCl_3$ and Se powder in solvent. The CIGS thin films were deposited on a sodalime glass. The CIGS thin film were identified to have a typical chalcopyrite tetragonal structure by using UV/Vis-spectroscopy, X-ray diffraction(XRD), Auger Electron Spectroscopy(AES), Scanning Electron Microscopy(SEM).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.102-107
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• 2003

This study puts focus on the optimization of growth temperature of CIGS absorber layer which affects severely the performance of solar cells. The CIGS absorber layers were prepared by three-stage co-evaporation of metal elements in the order of In-Ga-Se. The effect of the growth temperature of 1st stage was found not to be so important, and 350$^{\circ}C$ to be the lowest optimum temperature. In the case of growth temperature at 2nd/3rd stage, the optimum temperature was revealed to be 550$^{\circ}C$. The XRD results of CIGS films showed a strong (112) preferred orientation and the Raman spectra of CIGS films showed only the Al mode peak at 173cm$\^$-1/. Scanning electron microscopy results revealed very small grains at 2nd/3rd stage growth temperature of 480$^{\circ}C$. At higher temperatures, the grain size increased together with a reduction in the number of the voids. The optimization of experimental parameters above mentioned, through the repeated fabrication and characterization of unit layers and devices, led to the highest conversion efficiency of 15.4% from CIGS-based thin film solar cell with a structure of Al/ZnO/CdS/CIGS/Mo/glass.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.153-155
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• 2009

In this study, we fabricated the $Cu(In,Ga)Se_2$ (CIGS) thin-film solar cells by using a polyimide substrate. The CIGS thin-film was deposited on Mo coated polyimide substrate by a 3-stage co-evaporation technique. Because the polyimide shows thermal transformation at about $400^{\circ}C$, the substrate temperature of co-evaporation process was set to below $400^{\circ}C$. Corresponding solar cell showed a conversion efficiency of 7.08 % with $V_{OC}$ of 0.58 V, $J_{SC}$ of 24.99 $mA/cm^2$ and FF of 0.49.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.3
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• pp.1-5
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• 2000

Inductively coupled plasma (ICP) excited by a spiral planar antenna is used to etch elctrodes for PZT capacitors. Pt/RuO$_{2}$ bilayers are tested as bottom electrodes for PZT capacitors in order to utilize better leakage characteristics of Pt and easy etch characteristics of RuO$_{2}$ at the same time. The etch rates and selectivities to SiO$_{2}$ hard mask have been measured for each of Pt and RuO$_{2}$ in terms of various plasma conditions. As Cl$_{2}$ ratio increases in $O_{2}$/Cl$_{2}$ mixture, the etch rate of Pt increases while that of RuO$_{2}$ reaches the highest near 10 ％ of Cl$_{2}$. Optimum gas mixture ratio has been determined for etching Pt and RuO$_{2}$ bilayers sequentially, and sub-half micron patterning is demonstrated.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1331-1332
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• 2007

In the present works, we investigate the thermal characteristics on Ag/$As_{2}S_{3}$ and Ag/$As_{40}Ge_{10}Se_{15}S_{35}$ amorphous chalcogenide thin film structure for PMC (Programmable Metallization Cell).As the results of resistance change with the temperature on Ag/$As_{40}Ge_{10}Se_{15}S_{35}$ amorphous chalcogenide thin film, the resistance was abruptly dropped from the initial resistance of 1.32 M ${\Omega}$ to the saturated value of 800 ${\Omega}$ at $203^{\circ}C$. On the other hand, the resistance increased to 1.3 $M{\Omega}$ at $219^{\circ}C$.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.81-86
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• 1993

Polycrystalline CdSe thin films were grown on ceramic substrate using a chemical bath deposition (CBD) method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdSe polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdSe samples annealed in $N_{2}$ gas at $450^{\circ}C$ it was found hexagonal structure whose lattice parameters $a_{o}$ and $c_{o}$ were $4.302{\AA}$ and $7.014{\AA}$, respectively. Its grain size was about $0.3{\mu}m$. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33 K and 200 K, and by polar optical scattering at temperature range of 200 K and 293 K. We measured also spectral response, sensitivity (${\gamma}$), maximum allowable power dissipation and response time on these samples.

• Current Photovoltaic Research
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• v.4 no.1
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• pp.21-24
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• 2016

Chalcopyrite based (CIGS) thin films have considered to be a promising candidates for industrial applications. The growth of quality CIGS thin films without secondary phases is very important for further efficiency improvements. But, the identification of complex secondary phases present in the entire film is crucial issue due to the lack of powerful characterization tools. Even though X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and normal Raman spectroscopy provide the information about the secondary phases, they provide insufficient information because of their resolution problem and complexity in analyzation. Among the above tools, a normal Raman spectroscopy is better for analysis of secondary phases. However, Raman signal provide the information in 300 nm depth of film even the thickness of film is > $1{\mu}m$. For this reason, the information from Raman spectroscopy can't represent the properties of whole film. In this regard, the authors introduce a new way for identification of secondary phases in CIGS film using depth Raman analysis. The CIGS thin films were prepared using DC-sputtering followed by selenization process in 10 min time under $1{\times}10^{-3}torr$ pressure. As-prepared films were polished using a dimple grinder which expanded the $2{\mu}m$ thick films into about 1mm that is more than enough to resolve the depth distribution. Raman analysis indicated that the CIGS film showed different secondary phases such as, $CuIn_3Se_5$, $CuInSe_2$, InSe and CuSe, presented in different depths of the film whereas XPS gave complex information about the phases. Therefore, the present work emphasized that the Raman depth profile tool is more efficient for identification of secondary phases in CIGS thin film.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.671-671
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• 2013

실리콘 태양전지와 박막형 태양전지의 뒤를 이어, 제3세대로 분류되는 양자점 감응형 태양전지(QDSC)에 대한 연구가 활발히 진행되고 있다. 이 태양전지의 TCO로는 주로 ZnO, TiO2가 대부분 사용되고 있으며, 양자점 물질로는 CdS, CdSe, CdTe, PbS, PbSe 등의 카드뮴 및 납을 주 성분으로 하는 물질들에 대한 연구만 중점적으로 이루어지고 있는 실정이다. 이런 물질들은 현재까지 알려진 한도 내에서는 QDSC 효율 중 가장 좋은 효율을 나타내고는 있으나 이런 타입의 QDSC가 상용화된다면 환경에 노출되었을 때에 미치는 악영향이 매우 큰 중금속 물질들로 이루어져 있어, 이를 극복할 수 있는 친환경 성분의 물질에 대한 연구 또한 필요한 시점이다. 따라서 본 연구에서는 CdS를 대체할 수 있는 물질로 Ag2S를 선정, 이에 대한 연구를 진행하였다. Ag2S는 밴드갭이 1.1eV의 물질로, CdS의 2.3 eV와 비교해 상당히 작은 밴드갭을 가져 월등히 넓은 영역에서 빛을 흡수할 수 있다는 장점을 가지고 있으며, 동시에 이로 인한 전자-정공 재결합이 빨라 태양전지로 제작시에 Voc가 낮게 형성된다는 단점도 가지고 있다. 태양전지에 사용된 TCO물질은 ZnO 나노선을 사용했으며, 본 연구실에서 기존에 개발한 수열합성법을 통해 제작하였다. 이를 활용하여 최종적으로 제작한 태양전지의 효율은 CdS/ZnO QDSC가 1.2%, Ag2S/ZnO QDSC가 1.2%로 동일한 성능을 나타냈으며, CdS를 대체할 물질로 Ag2S의 가능성을 보여준 결과라 할 수 있다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.9
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• pp.755-759
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• 2011

$Cu(In_{1-x},Ga_x)Se_2$ thin films have been considered as an effective absorber material for high efficient solar cells. In this paper, the CIGS thin films with varied Ga content were prepared using a co-evaporation process of three stage. We carry out structure and electrical optical property on the thin film in varied Ga content. CIGS thin films have been characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), energy-dispersive spectroscopy(EDS), four-point probe measurement, and the Hall measurement. To optimize Ga contents, Ga/(In+Ga) ratio were changed from 0.13 to 0.72. At this time the carrier concentrations were varied from $1.22{\times}10^{11}\;cm^{-3}$ to $5.07{\times}10^{16}\;cm^{-3}$, and electrical resistivity were varied from $1.11{\times}10^0\;{\Omega}-cm$ to $1.08{\times}10^2\;{\Omega}-cm$. A strong <220/204> orientation and a lager grain size were obtained at a Ga/(In+Ga) of 0.3. We were able to achieve conversion efficiency as high as 15.95% with a Ga/(In+Ga) of 0.3.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.307-310
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• 1999

Using Se as a photoconductive element and ZnS as a luminescent element, a Se/ZnS thin film device for light amplifier applications was fabricated and its characteristics were investigated. The Se/ZnS thin film light amplifier was fabricated by evaporating the ZnS thin film on an ITO(Indium Tin Oxide) glass and the Se thin film on the ZnS thin film in sequence. The results of the characteristics investigation are summarized as follows: (1) When the frequency of an excitation voltage was increased, both the brightness response and the brightness saturation of the Se/ZnS thin film light amplifier began to start at a higher light input. (2) The gain of the Se/ZnS thin film light amplifier was dependent upon the amplitude and the frequency of the excitation voltage as well as an external light input. (3) When the Se/ZnS thin film light amplifier was excited by a direct current of a constant voltage, the frequency of the output brightness was\\`equal to the frequency of the input light applied. When the light amplifier was excited by a sinusoidal voltage of 60 Hz, the frequency of the output brightness was 120 Hz.