• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.4
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• pp.326-332
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• 2008

In this work CdS films were prepared by using chemical bath deposition, which is simple and inexpensive technique suitable for large deposition area. Annealing in air at different temperatures (300, 350, 400, 450 and $500^{\circ}C$) at constant time of 30 min, also for different times (15, 30, 45, 60 and 90 min) at constant temperature ($300^{\circ}C$) is achieved. X-Ray analysis has confirmed the formation of cadmium oxide (CdO) with slight increase in grain size, shift towards lower scattering angle due to relaxation in the tensile strain for deposition films, and structure change from cubic and hexagonal to the hexagonal. From electrical properties, significant increase in electrical conductivity appeared in samples annealed at $300^{\circ}C$ for 60 min, and at $350^{\circ}C$ for 30 min.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.413-418
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• 2021

Nano-materials with high effective surface areas have been applied to functional materials, such as high sensitive gas sensors and biosensors and high-efficiency catalytic materials. In this study, titanate sheets with a 3D nano-wall-like structure, high effective surface area, were synthesized vertically to the substrate by a chemical bath deposition (CBD) process using a Ti sheet and urea. The synthesis temperature and synthesis duration time were controlled to the optimal conditions of a 3D nano-wall-like structure in the CBD process. The synthesized ammonium titanate sheets with a 3D nano-wall-like structure were annealed in air to transform to TiO2 with a 3D nano-wall-like structure for various applications. As a result, the optimal temperature in the CBD process for the synthesis of a uniform ammonium titanate sheet with a 3D nano-wall-like structure was 90 ℃. TiO2 with a 3D nano-wall-like structure was obtained from the ammonium titanate sheet with a 3D nano-wall-like structure by annealing above 550 ℃ for three hours. In particular, TiO2 with a 3D nano-wall-like structure with a dominant rutile phase was obtained by post-annealing at 700 ℃. On the other hand, damage to the 3D nano-wall edge was observed after 700 ℃ post-annealing.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.664-668
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• 2012

ZnO nanorods were successfully fabricated on Zn foil by chemical bath deposition (CBD) method. The ZnO precursor concentration and immersion time affected the surface morphologies, structure, and electrical properties of the ZnO nanorods. As the precursor concentration increased, the diameter of the ZnO nanorods increased from ca. 50 nm to ca. 150 nm. The thicknesses of the ZnO nanorods were from ca. $1.98{\mu}m$ to ca. $2.08{\mu}m$. ZnO crystalline phases of (100), (002), and (101) planes of hexagonal wurtzite structure were confirmed by XRD measurement. The fabricated ZnO nanorods showed a photoluminescene property at 380 nm. Especially, the ZnO nanorods deposited for 6 h in solution with a concentration of 0.005M showed a stronger (101) peak than they did (100) or (002) peaks. In addition, these ZnO nanorods showed a good electrical property, with the lowest resistance among the four samples, because the nanorods were densely in contact and relatively without pores. Therefore, a ZnO nanorod substrate is useful as a highly sensitive biochip substrate to detect biomolecules using an electrochemical method.

• Korean Journal of Materials Research
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• v.22 no.10
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• pp.504-507
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• 2012

Synthesis of RGO (reduced graphene oxide)-CdS composite material was performed through CBD (chemical bath deposition) method in which graphene oxide served as the support and Cadmium Sulfate Hydrate as the starting material. Graphene-based semiconductor photocatalysts have attracted extensive attention due to their usefulness for environmental and energy applications. The band gap (2.4 eV) of CdS corresponds well with the spectrum of sunlight because the crystalline phase, size, morphology, specic surface area and defects, etc., of CdS can affect its photocatalytic activity. The specific surface structure (morphology) of the photocatalyst can be effective for the suppression of recombination between photogenerated electrons and holes. Graphene (GN) has unique properties such as a high value of Young's modulus, large theoretical specific surface area, excellent thermal conductivity, high mobility of charge carriers, and good optical transmittance. These excellent properties make GN an ideal building block in nanocomposites. It can act as an excellent electron-acceptor/transport material. Therefore, the morphology, structural characterization and crystal structure were observed using various analytical tools, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. From this analysis, it is shown that CdS particles were well dispersed uniformly in the RGO sheet. Furthermore, the photocatalytic property of the resulting RGO-CdS composite is also discussed in relation to environmental applications such as the photocatalytic degradation of pollutants. It was found that the prepared RGO-CdS nanocomposites exhibited enhanced photocatalytic activity as compared with that of CdS nanoparticles. Therefore, better efficiency of photodegradation was found for water purification applications using RGO-CdS composite.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.1-4
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• 2004

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 $a_0$ and $c_0$ 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 movility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33K and 200K, and by polar optical scattering at temperature range of 200K and 293K. We measured also spectral response, sensitivity$(\gamma)$, maximum allowable power dissipation and response time on these samples.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.146-148
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• 2012

In our study, we have focused on optimizing good quality of ZnS buffer layer by chemical bath deposition (CBD) from a bath containing $ZnSO_4$, Thiourea and Ammonia in aqueous solution onto CIGS solar cells. The influence of deposition parameter such as pH, deposition temperature, stirring speed played a very important role on transmission, homogeneity, crystalline of ZnS buffer layer. The transmission spectrum showed a good transmission characteristic above 80% invisible spectral region. CIGS thin flim solar cell with ZnS buffer layer has been realized with the efficiency of 14.2%.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.294-294
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• 2010

CdS는 $CuInSe_2$계, CdTe계 이종접합 태양전지의 junction partner로 많이 이용되어 왔다. CdS는 전극으로 쓰일 뿐만 아니라 빛을 투과시키는 창문층으로 사용되어 높은 변환 효율을 나타낸다. 이종접합 태양전지에서 창문층은 가시광 영역에서 광투과율이 높고, 전기적으로 비저항이 낮아야 에너지 손실 없이 태양광을 광흡수층까지 투과시킬 수 있다. CdS 박막은 CBD법(solution growth technique), 진공증착법(vacuum evaporation), 스퍼터법(sputtering), 스프레이 열분해법(spray pyrolysis), 전착법(electrodeposition)에 의해 제조되고, 그 중 용액성장법(solution growth technique)이라고도 불리는 CBD법(chemical bath deposition)을 이용하여 CdS 박막을 제조하였다. CBD법은 다른 방법에 비해 제조 과정이 비교적 간단할 뿐만 아니라 제조 단가가 저렴하고, 넓은 면적의 박막 제조가 가능하며 재현성도 우수하다는 장점이 있다. CdS 박막을 제조하기 위한 cadmuim 이온공급원으로는 $CdSO_4$를 사용하였고 sulfur 이온공급원으로는 $SC(NH_2)_2$를 사용하였다. CBD법에서 박막의 물성에 영향을 미칠 수 있는 요인인 sulfur 이온공급원과 cadmium 이온공급원의 비, 용액의 온도, pH를 변화시켜 CdS 박막을 제조하였다. 각각의 조건에 의해 제조된 CdS의 박막의 두께는 Tencor P-1을 이용하여 측정되었고, UV-Visible spectrometer를 이용하여 파장에 따른 광투과율을 측정하였다. CdS 박막의 결정 구조를 조사하기 위해 X선 회절분석(XRD ; X-ray diffraction)을 하였고, AFM(Atomic Force Microscope)으로 표면 특성을 관찰하였다.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.577-580
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• 2014

Indium hydroxy sulfide ($In(OH)_xS_y$) as a cadmium (Cd)-free buffer layer for $CuInGaSe_2$ (CIGS) solar cells was prepared by the chemical bath deposition (CBD) and the reaction time was optimized. The band gap energy and transmittance data alongside the thickness results from the direct observation with focused ion beam system (FIB) could be a powerful tool for optimizing the conditions. In addition, X-ray diffractometer (XRD), X-ray photoelectron microscopy (XPS), and scanning electron microscope (SEM) were also employed for the layer characterization. The results indicated that the optimum reaction time for $In(OH)_xS_y$ buffer layer deposition by CBD was 20 min at $70^{\circ}C$ under the conditions employed. At the optimum conditions, the buffer layer thickness was near 57 nm and the band gap energy was 2.7 eV. In addition, it was found that there was no XPS peak shift in between the buffer layers deposited on molybdenum (Mo)/glass and that on CIGS layer.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.2
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• pp.117-123
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• 2009

$Pb_{x}Cd_{1-x}S$ films are prepared in the composition range of 0.05${\leq}x{\leq}$0.25, using a chemical bath deposition growth technique under optimum conditions amide at realizing good photo response. The x-ray diffraction results show that the films are of PbS-CdS composite with individual CdS and PbS planes. The films exhibit two direct band gaps, 2.4 eV attributed to CdS, while the other varies continuously from 2.4 eV to 1.3 eV. The films surface morphology is smooth with crystallite, whose grain size increases with increasing mole fraction (x). The decrease in band gap with increase in lead concentration suggests inter-metallic compound of PbS (Eg=0.41 eV) with CdS (Eg=2.4 eV)

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.461.2-461.2
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• 2014

양자점은 밴드갭을 조절할 수 있거나 multiple exciton generation등 과 같은여러가지 장점을 갖고 있어 양자점 감응형 태양전지에 대한 많은 연구가 진행되어왔다. 하지만 아직까지 이론적인 에너지 전환 효율에 비하여 낮은 효율을 보여주고 있다. 이러한 낮은 효율은 양자점과 전해질 계면에서의 defect나 surface state로 인한 전자-정공의 재결합으로 설명할 수 있다. 본 연구에서는 CdSe 양자점 합성법 중의 하나인 Chemical Bath Deposition의 전구체 농도조절을 통하여 고품질의 CdSe양자점을 합성하였다. 특정 농도에서 CdSe 양자점 표면에 생성되는 SeO2층을 억제하여 CdSe양자점/전해질 계면에서의 전하 재결합 저항을 높였고 가장 높은 에너지 전환 효율을 보여주었다.