• 열처리공학회지
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• 제25권5호
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• pp.239-243
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• 2012

$SnO_2$ thin films were prepared on the Si substrate by radio frequency (RF) magnetron sputtering and then post deposition vacuum annealed to investigate the effect of annealing temperature on the structural properties and hydrogen gas sensitivity of the films. The films that annealed at $300^{\circ}C$ show the higher sensitivity than the other films annealed at $150^{\circ}C$. From atomic force microscope observation, it is supposed that post deposition annealing promotes the rough surface and also, increase gas sensitivity of $SnO_2$ films for hydrogen gas. These results suggest that the vacuum annealed $SnO_2$ thin films at optimized temperatures are promising for practical high-performance hydrogen gas sensors.

• 한국전기전자재료학회논문지
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• 제19권7호
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• pp.680-686
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• 2006

Tin oxide$(SnO_2)$ thin films were prepared on glass substrate by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. $SnO_2$ thin films were prepared using gas mixture of dibutyltin diacetate as a precursor and oxygen as an oxidant at 275, 325, 375, $425^{\circ}C$, respectively as a function of deposition temperature. The XRD peaks corresponded to those of polycrystalline $SnO_2$, which is in the tetragonal system with a rutil-type structure. As the deposition temperature increased, the texture plane of $SnO_2$ changed from (200) plane to denser (211) and (110) planes. Lower deposition temperature and shorter deposition time led to decreasing surface roughness and electrical resistivity of the formed thin films at $325\sim425^{\circ}C$. The properties of $SnO_2$ films were critically affected by deposition temperature and time.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.272-272
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• 2014

SnO thin films, 100 nm in thickness, were deposited on glass substrates by RF magnetron sputtering. A stack structure of $SnO_2/SnO$, where few nanometers of $SnO_2$ were determined on the SnO thin film by X-ray photoelectron spectroscopy. In addition, XPS depth profile analysis of the pristine and heat treated thin films were introduced. The electrical behavior of the as-sputtered films during the annealing was recorded to investigate the working conditions for the SnO sensor. Subsequently, The NH3 sensing properties of the SnO sensor at operating temperature of $50-200^{\circ}C$ were examined, in which the p-type semiconducting sensing properties of the thin film were noted. The sensor shows good sensitivity and repeatability to $NH_3$ vapor. The sensor properties toward several gases like $H_2S$, $CH_4$ and $C_3H_8$ were also introduced. Finally, a sensing mechanism was proposed and discussed.

• 한국세라믹학회지
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• 제46권4호
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• pp.429-435
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• 2009

In this study, we investigated microstructure and the CO gas sensing properties of Ag-CuO-$SnO_2$ thin films prepared by co-evaporation and subsequently thermal oxidation at air atmosphere. The sensitivity of a Cu-Sn films, thermally oxidized at $600^{\circ}C$, is strongly affected by the amount of Cu. At Cu:7 wt%-Sn:93 wt%, the film exhibited a maximum sensitivity of ${\sim}2.3$ to CO gas of 1000 ppm at $300^{\circ}C$. In contrast, the sensitivity of a Sn-Ag film did not change significantly with the amount of Ag. An enhanced sensitivity of ${\sim}3.7$ was observed in the film with a composition of Ag:3 wt%-Cu:4 wt%-Sn:93 wt%, when thermally oxidized at $600^{\circ}C$. In addition, this thin film shows a response time of ${\sim}80$ sec and a recovery time of ${\sim}450$ sec to 1000 ppm CO gas. The results demonstrate that the CO sensitivity of the Ag-CuO-$SnO_2$ thin films may be closely associated with coexistence of $SnO_2$ and SnO phase, decrease in average particle size, and a porous microstructure. We also suggest that co-evaporation and followed by thermal oxidation is a very simple and effective method to prepare oxide gas sensor thin films.

• 한국진공학회지
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• 제10권3호
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• pp.289-297
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• 2001

가연성 가스의 검지 및 인식을 위하여, SnO$_2$계열의 4가지 종류의 박막을 형성하였다. 감지막 형성을 위하여, Sn, Pt/Sn, Au/Sn 그리고 Pt, Au/Sn 막을 Sn의 열증착과 귀금속의 스퍼터링으로 증착하였다. 증착된 박막들을 $700^{\circ}C$ 정도에서 2 시간 열산화시켜 $SnO_2$계열의 감지막을 형성하였다. 제작된 박막은 tetragonal구조의 $SnO_2$이었고, 가스 흡착을 위한 가스 흡착점과 기공도를 많이 갖고 있었다. 스퍼터로 형성된 박막보다 열산화법으로 형성된 박막이 고감도를 보였다. 제작 박막들은 작업환경기준치정도의 저농도에서 측정 가연성 가스(부탄, 프로판, LPG, 일산화탄소)에 대해 고감도와 재현성을 나타내었다. 특히, 백금(30 $\AA$)을 첨가한 박막이 LPG와 부탄 가스에 대해, 순수 열산화된 $SnO_2$ 박막이 프로판과 일산화탄소에 대하여 가장 고감도를 나타내었다. 이들 센서들의 각 가스별로 차별화된 감도패턴을 이용하여 주성분 분석 기법을 통해 환경기준치(LEL, TLV) 범위에서 부탄, 프로판, LPG, 일산화탄소와 같은 가연성 가스의 종류 인식 및 정량을 인식할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.262-263
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• 2007

Effect of co-doping on optical and electrical properties of $SnO_2$ based thin films were studied. $SnO_2$ ceramic targets with up to 50mol% $CuSb_2O_6$ were prepared by sintering mixed-oxide compact in the temperature range of $1100^{\circ}C{\sim}1300^{\circ}C$ in air. Thin films were then deposited onto glass substrates by pulsed laser deposition where substrate temperature was maintained in the range of $500{\sim}650^{\circ}C$ with oxygen pressure of 3m~7.5mTorr and energy density of $1Jcm^{-2}$. It was found that with the increase amount of dopant, the electrical properties of thin films tended to improve with the smallest resistivity value obtained at about 8mol% doping, further increase, however, usually impaired the optical transmission in the visible range.

• 대한금속재료학회지
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• 제49권4호
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• pp.329-333
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• 2011

To develop wide-band noise absorbers with a special design for low-frequency performance, this study proposes a tin oxide (Sn-O) thin films as the noise absorbing materials in a microstrip line. Sn-O thin films were deposited on polyimide film substrates by reactive sputtering of the Sn target under flowing $O_{2}$ gas, exhibiting a wide variation of surface resistance (in the range of $10^{0}-10^{5}{\Omega}$) depending on the oxygen partial pressure during deposition. The microstrip line with characteristic impedance of $50\Omega$ was used for the measurement of noise absorption by the Sn-O films. The reflection parameter $(S_{11})$ increased with a decrease of surface resistance due to an impedance mismatch at the boundary between the film and the microstrip line. Meanwhile, the transmission parameter $(S_{21})$ diminished with a decrease of surface resistance resulting from an Ohmic loss of the Sn-O films. The maximum noise absorption predicted at an optimum surface resistance of the Sn-O films was about $150{\Omega}$. For this film, greater power absorption is predicted in the lower frequency region (about 70% at 1 GHz) than in conventional magnetic sheets of high magnetic loss, indicating that Ohmic loss is the predominant loss parameter for the conduction noise absorption in the low frequency band.

• 열처리공학회지
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• 제29권5호
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• pp.216-219
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• 2016

$SnO_2$ single layer films (100 nm thick) and 2 nm thick Ni intermediated $SnO_2$ films were deposited on glass substrate by RF and DC magnetron sputtering without intentional substrate heating and then the influence of the Ni interlayer on the electrical and optical properties of the films were investigated. As deposited $SnO_2$ single layer films show the optical transmittance of 82.6% in the visible wavelength region and a resistivity of $6.6{ \times}10^{-3}{\Omega}cm$, while $SnO_2/Ni/SnO_2$ trilayer films show a lower resistivity of $2.7{ \times}10^{-3}{\Omega}cm$ and an optical transmittance of 76.3% in this study. Based on the figure of merit, it can be concluded that the intermediate Ni thin film effectively enhances the opto-electrical performance of $SnO_2$ films for use as transparent conducting oxides in flexible display applications.

• 열처리공학회지
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• 제32권2호
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• pp.74-78
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• 2019

$Zn_2SnO_4$ thin films were deposited on quartzs substrates by using radio-frequency magnetron sputtering system. Thermal treatments at various temperatures were performed to evaluate the effect of annealing temperatures on the properties of $Zn_2SnO_4$ thin films. Surface morphologies were examined by using field emission-scanning electron microscopy and showed that sizes of grains were slightly increased and grain boundaries were clear with increasing annealing temperatures. The deposited $Zn_2SnO_4$ thin films on quartzs substrates were amorphous structures and no distinguishable crystallographic changes were observed with variations of annealing temperatures. The optical transmittance was improved with increasing annealing temperatures and was over 90% in the wavelength region between 350 and 1100 nm at the annealing temperature of $600^{\circ}C$. The optical energy bandgaps, which derived from the absorbance of $Zn_2SnO_4$ thin films, were increased from 3.34 eV to 3.43 eV at the annealing temperatures of $450^{\circ}C$ and $600^{\circ}C$, respectively. As the annealing temperature was increased, the electron concentrations were decreased. The electron mobility was decreased and resistivity was increased with increasing annealing temperatures with exception of $450^{\circ}C$. These results indicate that heat treatments at higher annealing temperatures improve the optical and electrical properties of rf-sputtered $Zn_2SnO_4$ thin films.

• 한국재료학회지
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• 제20권9호
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• pp.494-499
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• 2010

Tin oxide thin films were prepared on borosilicate glass by rf reactive sputtering at different deposition powers, process pressures and substrate temperatures. The ratio of oxygen/argon gas flow was fixed as 10 sccm / 60 sccm in this study. The structural, electrical and optical properties were examined by the design of experiment to evaluate the optimized processing conditions. The Taguchi method was used in this study. The films were characterized by X-ray diffraction, UV-Vis spectrometer, Hall effect measurements and atomic force microscope. Tin oxide thin films exhibited three types of crystal structures, namely, amorphous, SnO and $SnO_2$. In the case of amorphous thin films the optical band gap was widely spread from 2.30 to 3.36 eV and showed n-type conductivity. While the SnO thin films had an optical band gap of 2.24-2.49 eV and revealed p-type conductivity, the $SnO_2$ thin films showed an optical band gap of 3.33-3.63 eV and n-type conductivity. Among the three process parameters, the plasma power had the most impact on changing the structural, electrical and optical properties of the tin oxide thin films. It was also found that the grain size of the tin oxide thin films was dependent on the substrate temperature. However, the substrate temperature has very little effect on electrical and optical properties.