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This report examines the variation on structural properties of SnO2 thin films .TEM studies shows some of the interfaces to be atomically faceted. Secondary X-ray photoelectron Spectroscopy Analysis(XPS) depth profiles show that films have a uniform composition along the depth.

The triboelectric property of a material is important to improve an efficiency of triboelectric generator (TEG) in energy harvesting from an ambient energy. In this study, we have studied the TEG property of a semiconducting SnO2 which has yet to be explored so far. As a counter triboelectric material, PET and glass are used. Vertical contact mode is utilized to evaluate the TEG efficiency. SnO2 thin film is deposited by atomic layer deposition on bare Si wafer for various thicknesses from 5.2 nm to 34.6 nm, where the TEG output is increased from 13.9V to 73.5V. Triboelectric series are determined by comparing the polarity of output voltage of 2 samples among SnO2, PET, and glass. In conclusion, SnO2, as an intrinsic n-type material, has the most strong tendency to be positive side to lose the electron and PET has the most strong tendency to be negative side to get the electron, and glass to be between them. Therefore, the SnO2-PET combination shows the highest TEG efficiency.

SnO2-CoO/carbon-coated CoO core/shell nanowire composites were synthesized by using electrospinning andhydrothermal methods. In order to obtain SnO2-CoO/carbon-coated CoO core/shell nanowire composites, SnO2-Co3O4nanowire composites and SnO2-Co3O4/polygonal Co3O4 core/shell nanowire composites are also synthesized. To demonstratetheir structural, chemical bonding, and morphological properties, field-emission scanning electron microscopy,transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carried out. Theseresults indicated that the morphologies and structures of the samples were changed from SnO2-Co3O4 nanowires havingcylindrical structures to SnO2-Co3O4/Co3O4 core/shell nanowires having polygonal structures after a hydrothermal process. At last, SnO2-CoO/carbon-coated CoO core/shell nanowire composites having irregular and high surface area areformed after carbon coating using a polypyrrole (PPy). Also, there occur phases transformation of cobalt phases fromCo3O4 to CoO during carbon coating using a PPy under a argon atmosphere.

The present study demonstrates the effect of freezing conditions on the pore structure of porous Cu-10 wt.% Sn prepared by freeze drying of CuO-SnO2/camphene slurry. Mixtures of CuO and SnO2 powders are prepared by ball milling for 10 h. Camphene slurries with 10 vol.% of CuO-SnO2 are unidirectionally frozen in a mold maintained at a temperature of -30oC for 1 and 24 h, respectively. Pores are generated by the sublimation of camphene at room temperature. After hydrogen reduction and sintering at 650oC for 2 h, the green body of the CuO-SnO2 is completely converted into porous Cu-Sn alloy. Microstructural observation reveals that the sintered samples have large pores which are aligned parallel to the camphene growth direction. The size of the large pores increases from 150 to 300 μm with an increase in the holding time. Also, the internal walls of the large pores contain relatively small pores whose size increases with the holding time. The change in pore structure is explained by the growth behavior of the camphene crystals and rearrangement of the solid particles during the freezing process.

This work describes the coloration, chemical stability of SiO2 and SnO2-coated blue CoAl2O4 pigment. TheCoAl2O4, raw materials, were synthesized by a co-precipitation method and coated with silica (SiO2) and tin oxide(SnO2) using sol-gel method, respectively. To study phase and coloration of CoAl2O4, we prepared nano sized CoAl2O4pigments which were coated SiO2 and SnO2 using tetraethylorthosilicate, Na2SiO3 and Na2SnO3 as a coating material. Todetermine the stability of the coated samples and their colloidal solutions under acidic and basic conditions, colloidalnanoparticle solutions with various pH values were prepared and monitored over time. Blue CoAl2O4 solutions weretuned yellow color under all acidic/basic conditions. On the other hand, the chemical stability of SiO2 and SnO2-coatedCoAl2O4 solution were improved when all samples pH values, respectively. Phase stability under acidic/basic conditionof the core-shell type CoAl2O4 powders were characterized by transmission electron microscope, X-ray diffraction, CIEL*a*b* color parameter measurements.

In a view point of environment, the advanced electric contact material without environmental load element such as cadmium has to be developed. Extensive studies have been carried out on Ag-SnO2 electric contact material as a substitute of Ag-CdO contact materials. In the present study, powder metallurgy including compaction and sintering is introduced to solve the incomplete oxidation problems in manufacturing process of Ag-SnO2 electrical contact material. The Ag-SnO2 contact material, fabricated in this study, was actually set in an electric switchgear of which working voltage is 462V and current is between 25 and 40A, for the purpose of testing its performance. As a result, it exceeded the existing Ag-CdO contact materials in terminal-temperature ascent and main contact resistance.

Oxidation behavior and microstructural characteristics of nano-sized Sn powder were studied. DTA-TG analysis showed that the Sn powder exhibited an endothermic peak at 227℃ and exothermic peak at 560℃ with an increase in weight. Based on the phase diagram consideration of Sn-O system and XRD analysis, it was interpreted that the first peak was for the melting of Sn powder and the second peak resulted from the formation of SnO2 phase. Microstructural observation revealed that the SnO2 powder, heated to 1000℃ under air atmosphere, consisted of agglomerates with large particle size due to the melting of Sn powder during heat treatment. Finally, fine SnO2 powders with an average size of 50 nm can be fabricated by controlled heat treatment and ultrasonic milling process.

The result of examining the growth surface of the thin film through x-ray diffraction analysis of the SnO2 thin film with a changed deposition time, it was confirmed that the growth direction of the SnO2 thin film was grown in the direction of (110), (101), (200), (111), and (211) plane to form the SnO2 thin film in a rutile structure, and the growth intensity of the SnO2 thin film changed according to the deposition time. As a result of atomic analysis of the SnO2 thin film through a transmission electron microscope, it was confirmed that the oxygen atom first bonded with the silicon substrate to form a silicon oxide layer and then a tin oxide layer was formed, so the initial growth process of the SnO2 thin film could be interpreted as plasma ion bonding of oxygen gas molecules and tin between the substrate and the interface. As a result of analysis through transmission electron microscope elemental analysis, the atomic weight ratio of tin and oxygen in the SnO2 thin film was changed to 38.95%: 61.05%, 44.55%: 55.45%, 59.60%: 40.40%, 56.91%: 43.09%, and the atomic weight ratio was affected by the deposition time. The electrical resistance values of the SnO2 thin films varied as well, measuring 37.5 Kohm, 294.4 Kohm, 172.5 Kohm, and 18.43 Kohm, while the capacitance values changed to 659.8 nF, 2.634 nF, 1.077 nF, and 1.686 nF. These results indicate that the variation in deposition time has impact on the electrical properties of the SnO2 thin films.

Carbon nanofibers (CNF) are widely used as active agents for electrodes in Li-ion secondary battery cells, supercapacitors, and fuel cells. Nanoscale coatings on CNF electrodes can increase the output and lifespan of battery devices. Atomic layer deposition (ALD) can control the coating thickness at the nanoscale regardless of the shape, suitable for coating CNFs. However, because the CNF surface comprises stable C?C bonds, initiating homogeneous nuclear formation is difficult because of the lack of initial nucleation sites. This study introduces uniform nucleation site formation on CNF surfaces to promote a uniform SnO2 layer. We pretreat the CNF surface by introducing H2O or Al2O3 (trimethylaluminum + H2O) before the SnO2 ALD process to form active sites on the CNF surface. Transmission electron microscopy and energy-dispersive spectroscopy both identify the SnO2 layer morphology on the CNF. The Al2O3-pretreated sample shows a uniform SnO2 layer, while island-type SnOx layers grow sparsely on the H2Opretreated or untreated CNF.

In this study, we report the microstructure and characteristics of Ag-SnO2-Bi2O3 contact materials using a controlled milling process with a subsequent compaction process. Using magnetic pulsed compaction (MPC), the milled Ag-SnO2-Bi2O3 powders have been consolidated into bulk samples. The effects of the compaction conditions on the microstructure and characteristics have been investigated in detail. The nanoscale SnO2 phase and microscale Bi2O3 phase are well-distributed homogeneously in the Ag matrix after the consolidation process. The successful consolidation of Ag-SnO2-Bi2O3 contact materials was achieved by an MPC process with subsequent atmospheric sintering, after which the hardness and electrical conductivity of the Ag-SnO2-Bi2O3 contact materials were found to be 62?75 HV and 52?63% IACS, respectively, which is related to the interfacial stability between the Ag matrix, the SnO2 phase, and the Bi2O3 phase.

This study systematically investigates the dependence of the optical and electrical properties as a function of top SnO2 thicknessof SnO2/Ag/Nb2O5/SiO2/SnO2 multi-layer films deposited on a glass substrate at room temperature. The results of an EMPsimulation suggested that a multilayered thin film consisting of SnO2 (45 nm)/Ag (10 nm)/Nb2O5 (10 nm)/SiO2 (10 nm)/SnO2(30 nm) exhibited a high transmittance of 88.8% at 550 nm while the experimentally-measured transmittance showed 85.3%,which was somewhat lower than what is shown with the simulation data. The lowest Rs and ρ value were of about 5.81 Ω/sqand 5.81 × 10?5 Ω ? cm, and these were obtained with a multi-layered structure consisting of SnO2 (40 nm)/Ag (10 nm)/Nb2O5(10 nm)/SiO2 (10 nm)/SnO2 (30 nm). However, the sheet resistance and resistivity of the SnO2/Ag/ Nb2O5/SiO2/SnO2 multi layerfilm increased systematically with an increase in the thickness of the SnO2 layer from 40 to 55 nm. The ΦTC values of the SnO2/Ag/Nb2O5/SiO2/SnO2 multi layer films were shown to be in the range from 10.3 to 33.5 × 10?3 Ω?1.

A hybrid structure of SnO2/Ag/SnO2/SiO2/Nb2O5 was deposited on soda lime glass substrate by sequential RF/DC magnetronsputtering at room temperature and its optical and electrical properties were systematically investigated as a function of topSnO2 thickness. EMP simulation results suggested that a multilayered film of SnO2 (40 nm)/Ag (10 nm)/SnO2 (30 nm)/SiO2(10 nm)/Nb2O5 (10 nm) exhibited the highest visible transmittance of 90.1% at 550 nm, whereas experimentally measuredtransmittance showed 85.1%, somewhat lower than simulation data. The lowest Rs and ρ value were about 3.21 Ω/sq and 3.21× 10?5 Ω cm, acquired at the multi-layers with the structure of SnO2 (40 nm)/Ag (10 nm)/SnO2 (30 nm)/SiO2 (10 nm)/Nb2O5(10 nm). In addition, the sheet resistance and resistivity of SnO2/Ag/SnO2/SiO2/Nb2O5 multi layer films increased systematicallywith increasing the thickness of SnO2 layer from 40 to 55 nm. It was shown that the OTC values of SnO2/Ag/SnO2/SiO2/Nb2O5multi layer film were in the range of 46.4-62.1 × 10?3 Ω?1.

The reflectivity and colour variation in SnO2/Ag/SnO2/SiO2/Nb2O5 multi layer films on glass substrate were investigated withrespect to the top layer SnO2 thickness and IM (Index matching layer) layer. Initially SnO2/Ag/SnO2/SiO2/Nb2O5 multi layerfilms on glass substrate were deposited at room temperature by RF/DC magnetron sputtering method. EMP simulation resultssuggested that the multilayered thin film of SnO2 (40 nm)/Ag (10 nm)/SnO2 (30 nm)/SiO2 (10 nm)/Nb2O5 (10 nm) exhibited thehighest visible transmittance of 90.1% at 550 nm, whereas experimentally measured transmittance showed 85.1%, somewhatlower than simulation data. Reflectivities of SnO2 (40 nm)/Ag (10 nm)/SnO2 (30 nm)/SiO2 (10 nm)/Nb2O5 (10 nm) multi layerfilm at 450 nm and 550 nm of visible range, were 10.4% and 10.6% measured on the top of multi-layer film stackup,respectively. However, reflectivities with IM layer only were 10.8% and 12.4%, suggesting that reflectivity variation wasapproximately within 2%. From the L*a*b* colour space represented by reflectivity spectra, it was found that the lightness(+ L*) decreased from 91.2 to 89.4, whereas the yellowness (+ b*) increased from 0.77 to 1.47, with increasing SnO2 top layerthickness in multi-layer film.

유기물/무기물 나노 복합재료는 고온과 저전력에서 동작해야하는 차세대 전자 소자와 광소자 제작에 대단히 유용한 소재이다. 간단하고 저렴한 제조 방법과 휘어짐이 가능한 특성을 이용하여 유기물/무기물 나노 복합재료를 사용한 비휘발성 메모리 소자의 제작과 메모리 특성에 대한 연구가 수행되었으나, SnO2 나노 입자가 삽입된 고분자 박막을 기반으로 제작한 저항 구조의 비휘발성 메모리 소자인 유기 쌍안정성 소자에 대한 연구는 상대적으로 미흡하다. 본 연구에서는 poly(methyl methacrylate) (PMMA) 박막 안에 분산된 SnO2 나노 입자를 사용하여 제작한 유기 쌍안정성 소자의 메모리 특성을 관찰하였다. 소자를 제작하기 위해 나노 입자의 전구체인 Tin 2-ethylhexanoate을 dibutyl ether에 용해시킨 후, 화학적 방법을 사용하여 용매 안에서 SnO2 나노 입자를 합성하였다. 합성한 SnO2 나노 입자와 PMMA를 클로로벤젠에 용해하여 고분자 용액을 제작하였다. 전극인 indium-tin-oxide가 증착된 유리 기판 위에 제작한 고분자 용액을 스핀 코팅하고, 열을 가해 용매를 제거하여 SnO2 나노 입자가 분산되어 있는 PMMA 나노복합체를 형성하였다. 그 위에 Al 전극을 증착하여 유기 쌍안정성 소자를 완성하였다. 제작된 소자에 전압을 인가하여 전류를 측정한 결과 유기 쌍안정성 소자에서는 동일 전압에서 높은 전류 (ON 상태)와 낮은 전류 (OFF 상태)가 흐르는 쌍안정성 특성을 나타냈다. 그러나 SnO2 나노 입자가 없는 PMMA 박막으로 형성된 소자에서는 전류-전압 측정에서 쌍안정성 특성이 나타나지 않았다. 따라서 PMMA 박막 안에 삽입된 SnO2 나노 입자가 유기 쌍안정성 소자의 메모리 효과를 나타내는 원인임을 알 수 있었다. 전류-시간 측정 결과는 소자의 ON 상태 및 OFF 상태 전류가 시간에 따른 큰 변화 없이 1000 사이클 이상 지속적으로 유지 하고 있음을 보여 줌으로써 유기 쌍안정성 소자를 장시간 사용할 수 있음을 확인시켜 주었다.

투명전도성 산화물(TCO,Transparent Conductive Oxide) 물질로 널리 사용되는 ITO 박막은 산화물 반도체를 평판 디스플레이용 투명전극 재료로 개발하기 위한 많은 연구가 진행되고 있다. ITO (Indium tin oxide)는 약 3.5 eV 정도의 넓은 밴드갭을 가진 축퇴반도체로서 전기적 및 광학적 특성이 우수하기 때문에 대표적 투명전도성 박막으로 가장 많이 사용되고 있다.현재 양산화된 ITO의 조성비는 90:10WT%인 타겟을 사용하는대 투명전극은 비저항이 $1{\times}10-3{\Omega}/sq$이하로 면저항이 $103{\Omega}/sq$전기전도성이 우수하고 380에서 780 nm의 가시광선 영역에서의 투과율이 80% 이상이라는 두 가지 성질을 만족시키는 박막이다. 본 실험에서는 SnO2 1~5wt% 인 ITO타겟을 제작하고 RF-Magnetron Sputtering을 사용하여 영구자석을 이용한 고밀도 플라즈마로 높은 점착성과, 균일한 박막 및 대면적 공정이 가능한 RF-magnetron sputtering방법으로 기판인 Slide glass위에 ITO를 증착하여 광학적 특성 및 전기적 특성에 대하여 측정하였다. 전기적, 광학적 특성 등 XRD을 통해 분석하였다. 그리고 증착된 모든 ITO 박막에서 가시광 투과율을 측정하기 위해 UV-Vis spectrophptometer을 이용하여 분석한 결과 90%이상의 높은 투과율이 측정되었다. ITO박막은 Anti-Fogging, Self-Cleaning, Solar cell 및 디스플레이소자 등 다양한 산업에 이용 가능할 것으로 생각된다.

Zn-Sn-O (ZTO) 다성분계 산화물 박막은 일반적인 rf 스퍼터법으로 성막할 경우 비정질상으로 성장하여 결정질 산화물 박막에 비해 우수한 표면평탄도와 식각 단면을 제공한다. 비정질임에도 불구하고 넓은 자유전하 농도 범위에서 높은 Hall 이동도를 제공할 수 있는 것으로 보고되어 있어 비정질 산화물의 투명도전성 박막에 대한 관심이 높아지고 있다. 투명 TFT에 적용되는 또 다른 비정질계 산화물 박막인 In-Zn-O (IZO) 박막에 비해 ZTO 박막은 상대적으로 제한된 연구가 이루어졌으나, In의 함유되지 않아 경제적으로 유리하고, 특히 SnO2의 우수한 기계적 및 화학적 특성과 ZnO의 내환원성 특성을 잠재하고 있는 유망한 투명도전성 박막재료이다. 본 연구에서는 Zn-Sn-O계 박막을 통상의 rf 스퍼터법으로 성막하여 조성, 증착 온도, 그리고 열처리 온도에 따른 ZTO 박막의 구조적인 특성 변화와 이에 따른 전기적 및 광학적 특성 변화에 대하여 고찰하였다. ZnO 타겟과 SnO2 타겟을 사용하여 co-sputtering하여 ZnO의 부피 분률을 13~59 mol%까지 변화되도록 조절하여 증착하였다. 증착 온도는 상온, 150 및 $300^{\circ}C$로, 그리고 성막가스 중의 산소분률은 0%, 0.5% 및 1% 로 변화시켰다. 40 mol% 이상의 ZnO를 함유한 ZTO 박막은 가시광 영역에서의 평균 광투과도는 좋으나 전기적인 특성이 열악하였으며, ZnO 분율이 낮은 ZTO 박막은 10-2~10-3 ohm-cm 정도의 비교적 낮은 비저항을 나타내었으나 광투과도 면에서 떨어지는 단점을 보였다. 평균 광투과도는 증착 온도가 증가할수록, 그리고 산소의 양이 증가할수록 향상 되었다. 자유전하농도가 1017~1020 cm-3 정도의 넓은 범위에서 10 cm2/Vs 을 넘는 홀 이동도를 가지는 ZTO 박막의 증착이 가능함을 확인하였으며, 이로부터 투명 TFT 소자로 적용이 가능성이 있음을 보였다. EPMA를 이용한 정량분석 및 XRD를 이용한 구조분석과 연계한 ZTO 박막의 물성 및 최적 조건에 대한 논의가 이루어질 것이다.

We have investigated the effects of the oxygen gas flow ratio in a synthesis process, ultimately producing thin (~40 nm in diameter) SnO2 nanowires. Scanning electron microscopy revealed that the oxygen partial pressure affected the diameter as well as the length of the nanowires. An X-ray diffraction investigation suggested that the grain size of the SnO2 phase was slightly increased with a decrease in the oxygen partial pressure. Lattice-resolved transmission electron microscopy (TEM)images, selected area electron diffraction, and micro-Raman spectroscopy coincidentally showed that the as-synthesized nanowires comprised a tetragonal SnO2 phase. Based on the analysis by fabricating field effect transistors, we found that the transport properties of SnO2 nanowires exhibited an n-type semiconductor characteristic.