• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.2
• /
• pp.315-322
• /
• 2002

A thin film oxide semiconductor micro gas sensor array which shows only 60㎽ of power consumption at an operating temperature of 30$0^{\circ}C$ has been fabricated using microfabrication and rnicrornachining techniques. Excellent thermal insulation of the membrane is achieved by the use of a double la! or structure of 0.1${\mu}{\textrm}{m}$ thick Si$_3$N$_4$ and 1${\mu}{\textrm}{m}$ thick phosphosilicate glass(PSG) prepared by low pressure chemical vapor deposition(LPCVD) and atmospheric－pressure chemical-vapor deposition(APCVD), respectively. The sensor way consists of such thin film oxide semiconductor sensing materials as 1wt.％ Pd-doped SnO$_2$, 6wt.% AI$_2$O$_3$-doped ZnO, WO$_3$ and ZnO. The thin film oxide semiconductor micro gas sensor array exhibited resistance changes usable for subsequent data processing upon exposure to various gases and the sensitivity strongly depended on the sensing layer materials. Heater Part of the sensor structure has been modified in order to improve the process yield of the sensor, and as a result of modified heater structure improved process yield has been achieved.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.159-159
• /
• 2009

RF 스퍼터링법을 이용하여 유리기판위에 ZnO:Al 박막을 증착하고 다양한 조건 하에서 후 열처리를 실시하여 이에 따른 박막의 구조적, 전기적 및 광학적 특성과 HCl 습식 식각 후의 표면형상 변화를 조사하였다. ZnO:Al 투명전도막은 우수한 전기적, 광학적 특성, 수소 플라즈마 안정성 및 저 비용 등으로 실리콘 박막 태양전지 전면 전극용으로 많은 관심을 받고 있다. 기존의 비정질 실리콘 박막 태양전지용으로 많이 사용되고 있는 상용 Asahi-U형 ($SnO_2:F$) 투명전도막의 경우는 수소 플라즈마에 대한 안정성이 낮고 입사광의 장파장 대역에서의 낮은 산란특성으로 인하여 실리콘 박막 태양전지의 고효율화를 위한 적용에 한계를 나타내고 있다. 이를 개선하기 위하여 스퍼터링법으로 우수한 전기적 특성을 갖는 ZnO:Al 박막을 제조한 후 습식 식각을 통한 표면형상 변화를 통하여 입사광의 산란특성을 향상시키는 방법이 개발되어 많은 연구가 이루어지고 있다. 본 연구에서는 2.5 wt%의 $Al_2O_3$가 함유된 ZnO 타겟을 이용하여 ZnO:Al 박막을 RF 스퍼터링으로 증착한 후 $N_2$ 분위기와 진공 분위기 하에서 다양한 시간과 온도에 따라 후열처리를 하여 열처리 전 박막과의 물질 특성을 상호 비교하고 1%로 희석된 HCl로 습식 식각하여 열처리 전 박막의 구조적 특성이 습식 식각 후의 박막 표면형상 변화에 미치는 영향을 조사하였다. 이로부터 후열처리를 통한 ZnO:Al 투명전도막의 특성을 최적화하고 Asahi-U형 투명전도막과의 특성 비교를 통하여 실리콘 박막 태양전지용 전면전극으로의 적용 가능성을 조사하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.795-798
• /
• 2002

Replacing Pb-free glass composition for the dielectric materials is expected in PDP industry. In this study, phosphate glasses, $P_2O_5$- ZnO- SnO (PZS), $P_2O_5$-ZnO-BaO (PZB) were selected for a new transparent dielectric. Thermal properties (Tg, CTE) were measured with differential thermal analyzer and thermal mechanical analyzer. The glass transition of the glasses was ranged at $365{\sim}405^{\circ}C$ for the PZS system and $5.9{\sim}9.5{\times}\;10^{-6}$ of thermal expansion were found. The PZB system showed $445{\sim}470^{\circ}C$ of glass transition. Thus, the glass compositions would be a potential candidate for a transparent dielectric layer in plasma display panel.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.330-332
• /
• 2009

Highly stable bottom gate thin film transistors(TFTs) with a zinc indium tin oxide(Zn-In-Sn-O:ZITO) channel layer have been fabricated by rf-magnetron co-sputtering using a indium tin oxide(ITO:90/10), a tin oxide and a zinc oxide targets. The ZITO TFT (W/L=$40{\mu}m/20{\mu}m$) has a mobility of 24.6 $cm^2$/V.s, a subthreshold swing of 0.12V/dec., a turn-on voltage of -0.4V and an on/off ratio of >$10^9$. When gate field of $1.8{\times}10^5$ V/cm was applied with source-drain current of $3{\mu}A$ at $60^{\circ}C$, the threshold voltage shift was ~0.18 V after 135 hours. We fabricated AM-OLED driven by highly stable bottom gate Zn-In-Sn-O TFT array.

• Korean Journal of Materials Research
• /
• v.30 no.6
• /
• pp.285-291
• /
• 2020

Recent advances in technology using ultra-thin noble metal film in oxide/metal/oxide structures have attracted attention because this material is a promising alternative to meet the needs of transparent conduction electrodes (TCE). AZO/Ag/AZO multilayer films are prepared by magnetron sputtering for Cu₂ZnSn(S,Se)₄ (CZTSSe) of kesterite solar cells. It is shown that the electrical and optical properties of the AZO/Ag/AZO multilayer films can be improved by the very low resistivity and surface plasmon effects due to the deposition of different thicknesses of Ag layer between oxide layers fixed at AZO 30 nm. The AZO/Ag/AZO multilayer films of Ag 15 nm show high mobility of 26.4 ㎠/Vs and low resistivity and sheet resistance of 3.58^⁎10^-5 Ωcm and 5.0 Ω/sq. Also, the AZO/Ag (15 nm)/AZO multilayer film shows relatively high transmittance of more than 65 % in the visible region. Through this, we fabricated CZTSSe thin film solar cells with 7.51 % efficiency by improving the short-circuit current density and fill factor to 27.7 mV/㎠ and 62 %, respectively.

• Journal of the Korean institute of surface engineering
• /
• v.45 no.3
• /
• pp.117-122
• /
• 2012

ZTO/GZO double layered films were prepared on unheated non-alkali glass substrates. ZTO films were deposited by RF/DC hybrid magnetron co-sputtering using ZnO (RF) target and $SnO_2$ (DC) targets, and then GZO films were deposited by DC magnetron sputtering using an GZO ($Ga_2O_3$:5.57 wt%) target. These films were post-annealed at temperature of 200, $300^{\circ}C$ in air and vacuum ambient for 30 min. In the case of post-annealing in air, ZTO/GZO double layer showed relatively low resistivity change, compared to GZO single layer. Furthermore, ZTO/GZO double layer revealed low WVTR, compared to GZO single layer. Therefore, it can be confirmed that ZTO film doing a role with barrier for water or oxygen diffusion.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.79-79
• /
• 2013

Quantum-structures with nanoparticles have been attractive for various electronic and photonic devices [1,2]. In recent, nonvolatile memories such as nano-floating gate memory (NFGM) and resistance random access memory (ReRAM) have been studied using silicides, metals, and metal oxides nanoparticles [3,4]. In this study, we fabricated nonvolatile memories with silicides (WSi2, Ti2Si, V2Si) and metal-oxide (Cu2O, Fe2O3, ZnO, SnO2, In2O3 and etc.) nanoparticles embedded in polyimide matrix, and photovoltaic device also with SiC nanoparticles. The capacitance-voltageand current-voltage data showed a threshold voltage shift as a function of write/erase voltage, which implies the carrier charging and discharging into the metal-oxide nanoparticles. We have investigated also the electrical properties of ReRAM consisted with the nanoparticles embedded in ZnO, SiO2, polyimide layer on the monolayered graphene. We will discuss what the current bistability of the nanoparticle ReRAM with monolayered graphene, which occurred as a result of fully functional operation of the nonvolatile memory device. A photovoltaic device structure with nanoparticles was fabricated and its optical properties were also studied by photoluminescence and UV-Vis absorption measurements. We will discuss a feasibility of nanoparticles to application of nonvolatile memories and photovoltaic devices.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.3
• /
• pp.578-584
• /
• 2017

$SiO_2$ buffer layer (100 nm) has been deposited on PET substrate by electron beam evaporation. And then, IZTO (In-Zn-Sn-O) thin film has been deposited on $SiO_2$/PET substrate with different RF power of 30 to 60 W, working pressure, 1 to 7 mTorr, by RF magnetron sputtering. Structural, electrical and optical properties of IZTO thin film have been analyzed with various RF powers and working pressures. IZTO thin film deposited on the process condition of 50 W and 3 mTorr exhibited the best characteristics, where figure of merit was $4.53{\times}10^{-3}{\Omega}^{-1}$, resistivity, $4.42{\times}10^{-4}{\Omega}-cm$, sheet resistance, $27.63{\Omega}/sq.$, average transmittance (400-800 nm), 81.24%. As a result of AFM, all the IZTO thin film has no defects such as pinhole and crack, and RMS surface roughness was 1.147 nm. Due to these characteristics, IZTO thin film deposited on $SiO_2$/PET structure was found to be a very compatible material that can be applied to the next generation flexible display device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.11
• /
• pp.961-968
• /
• 2009

In this work, transparent conductive oxide(TCO) films such as $In_2O_3-SnO_2$(ITO) and $In_2O_3-ZnO$(IZO) were prepared on polyethylene naphthalene(PEN) and glass substrates by using rf-magnetron sputtering system. The TCO films deposited on PEN substrate show very poor conductivity as compared to that of the TCO films deposited on glass substrates. From the results of the residual gas analysis(RGA) test, this poor stability of plastic substrate is presumed to be caused by the deteriorated adhesion between the TCO films and the plastic substrate due to outgassing from the plastic substrate during deposition of TCO films. From our experiment, it is found that the vaporization of some defects in the plastic substrates deteriorate the adhesion of the TCO films to the plastic substrate, because the most plastic substrates containing the water vapor and/or other adsorbed particles such as organic solvents. Mixing of these gases vaporized in the sputtering process will also affect the electrical property of the deposited TCO films. Inorganic thin composite $(SiO_2)_{40}(ZnO)_{60}$ film as a gas barrier layer is coated on the PEN substrate to protecting the diffusion of vapors from the substrate, so that the TCO films with an improved quality can be obtained.

• Korean Journal of Materials Research
• /
• v.21 no.9
• /
• pp.491-496
• /
• 2011

Transparent conducting oxides (TCOs) used in the antireflection layer and current spreading layer of heterojunction solar cells should have excellent optical and electrical properties. Furthermore, TCOs need a high work function over 5.2 eV to prevent the effect of emitter band-bending caused by the difference in work function between emitter and TCOs. Sn-doped $In_2O_3$ (ITO) film is a highly promising material as a TCO due to its excellent optical and electrical properties. However, ITO films have a low work function of about 4.8 eV. This low work function of ITO films leads to deterioration of the conversion efficiency of solar cells. In this work, ITO films with various Zn contents of 0, 6.9, 12.7, 28.8, and 36.6 at.% were fabricated by a co-sputtering method using ITO and AZO targets at room temperature. The optical and electrical properties of Zn-doped ITO thin films were analyzed. Then, silicon heterojunction solar cells with these films were fabricated. The 12.7 at% Zn-doped ITO films show the highest hall mobility of 35.71 $cm^2$/Vsec. With increasing Zn content over 12.7, the hall mobility decreases. Although a small addition of Zn content increased the work function, further addition of Zn content over 12.7 at.% led to decreasing electrical properties because of the decrease in the carrier concentration and hall mobility. Silicon heterojunction solar cells with 12.7 at% Zn-doped ITO thin films showed the highest conversion efficiency of 15.8%.