• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.7
• /
• pp.473-478
• /
• 2001

Ferroelectric P $b_{0.99}$［(Z $r_{0}$ 6S $n_{0.4}$)/0.9/ $Ti_{0.1}$］0.98/N $b_{0.02}$ $O_3$(PNZST) thin films were deposited by a RF magnetron sputtering on L $a_{0.5}$S $r_{0.5}$Co $O_3$(LSCO)/Pt/Ti/ $SiO_2$/Si substrate using a PNZST target with excess PbO of 10 mole%. The crystallinity and electrical properties of the thin films annealed at various temperature and time were investigated. The thin films deposited at the substrate temperature of 500 $^{\circ}C$ and the power of 80 W were crystallized to a perovskite phase after rapid thermal annealing(RTA). The thin films annealed at 650 $^{\circ}C$ for 10 seconds in air exhibited the good crystal structures. The remanent polarization and coercive field of the PNZST capacitor were about 20 $\mu$C/$\textrm{cm}^2$ and 50 kV/cm, respectively. The reduction of the polarization after 2.2$\times$10$^{9}$ switching cycles was less than 10 %..10 %......

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.258-258
• /
• 2016

최근 디스플레이 산업의 발전에 따라 고성능 디스플레이가 요구되며, 디스플레이의 백플레인 (backplane) TFT (thin film transistor) 구동속도를 증가시키기 위한 연구가 활발히 진행되고 있다. 트랜지스터의 구동속도를 증가시키기 위해 높은 이동도는 중요한 요소 중 하나이다. 그러나, 기존 백플레인 TFT에 주로 사용된 amorphous silicon (a-Si)은 대면적화가 용이하며 가격이 저렴하지만, 이동도가 낮다는 (< $1cm2/V{\cdot}s$) 단점이 있다. 따라서 전기적 특성이 우수한 산화물 반도체가 기존의 a-Si의 대체 물질로써 각광받고 있다. 산화물 반도체는 비정질 상태임에도 불구하고 a-Si에 비해 이동도 (> $10cm2/V{\cdot}s$)가 높고, 가시광 영역에서 투명하며 저온에서 공정이 가능하다는 장점이 있다. 하지만, 차세대 디스플레이 백플레인에서는 더 높은 이동도 (> $30cm2/V{\cdot}s$)를 가지는 TFT가 요구된다. 따라서, 본 연구에서는 차세대 디스플레이에서 요구되는 높은 이동도를 갖는 TFT를 제작하기 위하여, amorphous In-Ga-Zn-O (a-IGZO) 채널하부에 화학적으로 안정하고 전도성이 뛰어난 SnO2 채널을 얇게 형성하여 TFT를 제작하였다. 표준 RCA 세정을 통하여 p-type Si 기판을 세정한 후, 열산화 공정을 거쳐서 두께 100 nm의 SiO2 게이트 절연막을 형성하였다. 본 연구에서 제안된 적층된 채널을 형성하기 위하여 5 nm 두계의 SnO2 층을 RF 스퍼터를 이용하여 증착하였으며, 순차적으로 a-IGZO 층을 65 nm의 두께로 증착하였다. 그 후, 소스/드레인 영역은 e-beam evaporator를 이용하여 Ti와 Al을 각각 5 nm와 120 nm의 두께로 증착하였다. 후속 열처리는 퍼니스로 N2 분위기에서 $600^{\circ}C$의 온도로 30 분 동안 실시하였다. 제작된 소자에 대하여 TFT의 전달 및 출력 특성을 비교한 결과, SnO2 층을 형성한 TFT에서 더 뛰어난 전달 및 출력 특성을 나타내었으며 이동도는 $8.7cm2/V{\cdot}s$에서 $70cm2/V{\cdot}s$로 크게 향상되는 것을 확인하였다. 결과적으로, 채널층 하부에 SnO2 층을 형성하는 방법은 추후 높은 이동도를 요구하는 디스플레이 백플레인 TFT 제작에 적용이 가능할 것으로 기대된다.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.41 no.5
• /
• pp.517-524
• /
• 1992

In this study, 0.10Pb(SbS11/2TSnS11/2T)OS13T-(0.90-x)PbZrOS13T (0.25 x 0.40) ceramics were fabricated by the atmospheric method. The sintering temperature and time were 1250[$^{\circ}C$] and 2[2hr], respectively. The structureal, dielectric and piezoelectric properties with composition of PbTiOS13T were studied. As the results of XRD ans SEM, the crystal structure of a specimen was rhombohedral, lattice constant and average grain size were decreased with increasing the contents of PbTiOS13T. Relative dielectric constant and Curie temperature were increased with increasing the contents of PbTiOS13T, 0.10PSS-0.40PT-0.50PZ specimen had the highest values of 904 and 265[$^{\circ}C$], respectively. In increasing of PbTiOS13T contents form 25[mol%] to 40[mol%], piezoelectric charge constant and electromechanical coupling factors were increased form 114[pC/N] to 142[pC/N], 17[%] to 24[%] and mechanical quality factor were decreased with increasing the contents of PbTiOS13T. In the 0.10PSS-0.40PT-0.50PZ specimens, those values were 14.2[kV/cm] and 9.43[x10S0-6TC/cmS02T], resectively.

• Journal of the Mineralogical Society of Korea
• /
• v.15 no.1
• /
• pp.78-84
• /
• 2002

New pyrochlore-type phases($A_2$$B_2$$O_{7}$) were synthesized in the systems: CaO-C$eO_2$-T$iO_2$, CaO-$UO_2$(T$hO_2$)-Z$rO_2$, CaO-$UO_2$(T$hO_2$)-$Gd_2$$O_3$-T$iO_2$-Z$rO_2$, 및 CaO-T$hO_2$-S$nO_2$. The starting materials were pressed with the pressure of 200~400 MPa and sintered at 1500~ 155$0^{\circ}C$ for 4~8 hours in air and at 1300~ 135$0^{\circ}C$ for 5 ~50 hours under oxygen atmosphere. The products were characterized using XRD, SEM/EDS and TEM. In the bulk compositions of CaCe$Ti_2$$O_{7}$, CaTh$Zr_2$$O_{7}$,($Ca_{0.5}$ Gd$Th_{0.5}$)(ZrTi)$O_{7}$) ($Ca_{0.5}$Gd$Th_{0.5}$)(ZrTi)$O_{7}$, ($Ca_{0.5}$G$dU_{0.5}$)(ZrTi)$O_{7}$ and CaTh$Sn_2$$O_{7}$ , pyrochlore was the major phase, together with other oxide phase $of_2$$O_{7}$ fluorite structure. In the samples with target compositions CaU$Zr_2$$O_2$및 $Ca_{0.5}$ G$dU_{0.5}$)$Zr_2$T$iO_{7}$ pyrochlore was not identified, but a fluorite-structured phase was detected. The formation factor as the stable phase depended on crystal chemical characteristics of the actinide and lanthanide elements of the system concerned.

• ETRI Journal
• /
• v.38 no.3
• /
• pp.469-478
• /
• 2016

In this paper, we investigate the effects of pre-reducing Sb-doped $SnO_2$ (ATO) electrodes in viologen-anchored $TiO_2$ (VTO) nanostructure-based electrochromic devices. We find that by pre-reducing an ATO electrode, the operating voltage of a VTO nanostructure-based electrochromic device can be lowered; consequently, such a device can be operated more stably with less hysteresis. Further, we find that a pre-reduction of the ATO electrode does not affect the coloration efficiency of such a device. The aforementioned effects of a pre-reduction are attributed to the fact that a pre-reduced ATO electrode is more compatible with a VTO nanostructure-based electrochromic device than a non-pre-reduced ATO electrode, because of the initial oxidized state of the other electrode of the device, that is, a VTO nanostructure-based electrode. The oxidation state of a pre-reduced ATO electrode plays a very important role in the operation of a VTO nanostructure-based electrochromic device because it strongly influences charge movement during electrochromic switching.

• Journal of Hydrogen and New Energy
• /
• v.13 no.1
• /
• pp.34-41
• /
• 2002

CdS and $TiO_2$ nanoparticles were made by the precipitation method and sol-gel method, respectively, and they were mixed mechanically and then treated with the hydrothermal processing. CdS-$TiO_2$ composite particulate films were thus prepared by casting CdS-$TiO_2$ mixed sol onto $SnO_2$ conducting glass and a subsequent heat-treatment at $400^{\circ}C$. Again, the physico-chemical and photoelectrochemical properties of these films were controlled by the surface treatment with $TiCl_4$ aqueous solution. The photocurrents and the hydrogen production rates measured under the present experimental conditions varied in the range of $3.5{\sim}4.5mA/cm^2$ and $0.3{\sim}1.8cc/cm^2$-hr, respectively, and showed the maximum values at the $CdS/[CdS+TiO_2]$ mole ratio of 0.2. Also, the surface treatment with $TiCl_4$ aqueous solution caused a considerable improvement in the photocatalytic activity, Probably as a result of close contacts between the primary particles by the etching effect of $TiCl_4$ It was found that the photoelectrochemical performance of these particulate films could be effectively enhanced by this approach.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.571-574
• /
• 2000

In this study, Tin oxide thin film for secondary battery was deposited on Pt/Ti/Si(100). It was fabricated by r.f. reactive sputtering with Tin metal target. At constant power (130W), pressure (Base 5$\times$10$^{-6}$ Torr, working 5$\times$10$^{-3}$ Torr) and at room temperature, it was fabricated by Ar/O2 gas ratio. After deposition, we got AFM & SEM to investigated surface of thin films and had XRD to find crystalline of thin films. Charge/discharge characteristics were carried out in 1M LiPF$_{6}$ , EC:DMC = 1:1 liquid electrolyte using lithium metal at room temperature.

• Journal of Korean Society for Atmospheric Environment
• /
• v.18 no.E1
• /
• pp.29-36
• /
• 2002

The selective catalytic reduction (SCR) reaction of promoter catalysts was investigated in this study. A pure anatase type of TiO$_2$ was used as support. Activation measurement of prepared catalysts was practiced on a fixed reactor packing by the glass bead after filling up catalysts in 1/4 inch stainless tube. The reaction temperature was measured by K-type thermocouple and catalyst was heated by electric furnace. The standard compositions of the simulated flue gas mixture in this study were as follows: NO 1,780ppm, NH$_3$1,780ppm, $O_2$1% and $N_2$ as balance gas. In this study, gas analyzer was used to measure the outgassing gas. Catalyst bed was handled for 1hr at 45$0^{\circ}C$, and the reactivity of the various catalyst was determined in a wide temperature range. Conversion of NH$_3$/NO ratio and of $O_2$ concentration was practiced at 1,1.5 and 2, respectively. The respective space velocity were as follows . 10,000, 15,000 and 17,000 hr-1. It was found that the maximum conversion temperature range was in a 5$0^{\circ}C$. It was also found toi be very sensitive at space velocity, $O_2$ concentration, and NH$_3$/NO ratio. We also noticed that the maximum conversion temperature of (W, Mo, Sn) -V$_2$O$_{5}$/TiO$_2$ catalysts was broad. Specially WO$_3$-V$_2$O$_{5}$TiO$_2$2 catalyst appeared nearly 100% conversion at not only above 30$0^{\circ}C$ ut also below 25$0^{\circ}C$. At over 30$0^{\circ}C$, NH$_3$ oxidation decreased with decrease of surface excess oxygen. In addition, WO$_3$-V$_2$O$_{5}$TiO$_2$ catalyst did not appear to affect space velocity, $O_2$ concentration, and NH$_3$/NO ratio.ratio.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.4
• /
• pp.302-306
• /
• 2009

9 kinds of nanoparticle used for this study was a particle with the size of less than 100 nm of diameter, and Artemia sp. cyst examined what kind of influence to have upon the process hatched out in nauplius. 82% hatched in nauplius at the opposition ward where a nanoparticle wasn't added after 24 time course. AGZ020, Nano silver, P-25, Sb and SnO nanoparticle showed hatching rate of 18%, 20%, 13%, 50% and 0% respectively by the 20mg/L density, and it became clear that a harmful effect is big, but I had a harmful effect compared with the opposition ward by 75%, 60%, 73% and 73% respectively by Ag-$TiO_2$, In, Sn and Zn nanoparticle, but a feeble thing was known relatively compared with AGZ020, Nano silver, P-25, Sb and SnO nanoparticle. The difference has caused this with the ingredient a nanoparticle has. Ag is included 2 % and AGZ020, Nano silver and P-25 nanoparticle are used widely as anti-fungus agent, and the SnO nanoparticle which became combination is a light catalyst pill, and oxygen is used for a Sn particle. This and others, a possibility that use is generalized and flows into aquatic environment in sequence the home electronics, functionality cosmetics, anti-fungus agent and a light catalyst pill at present becomes high for nanoparticles and others. The anxiety which has an influence on the ecology world in the water with this can be generated, so I'd have to study the potential danger a nanoparticle has continuously.

• Proceedings of KOSOMES biannual meeting
• /
• 2008.05a
• /
• pp.137-141
• /
• 2008

9 kinds of nanoparticle used for this study was a particle with the size of less than 100 nm of diameter, and Artemia sp. cyst examined what kind a influence to have upon the process hatched out in nauplius. 82% hatched in nauplius at the opposition ward where a nanoparticle wasn't added after 24 time course. AGZ020, Nano silver, P-25, Sb and SnO nanoparticle showed hatching rate of 18%, 20%, 13%, 50% and 0% respectively by the 20mg/L density, and it became clear that a harmful effect is big, but I had a harmful effect compared with the opposition ward by 75%, 60%, 73% and 73% respectively by Ag-$TiO_2$, In, Sn and Zn nanoparticle, but a feeble thing was known relatively compared with AGZ020, Nano silver, P-25, Sb and SnO nanoparticle. The difference was mused this with the ingredient a nanoparticle has. Ag is included 2% and AGZ020, Nano silver and P-25 nanoparticle are used widely as anti-fungus agent, and the SnO nanoparticle which became combination is a light catalyst pill, and oxygen is used for a Sn particle. This and others, a possibility that use is generalized and flows into aquatic environment in sequence the home electronics, functionality cosmetics, anti-fungus agent and a light catalyst pill at present becomes high for nanoparticles and others. The anxiety which has an influence on the ecology world in the water with this can be generated, so I'd have to study the potential danger a nanoparticle has continuously.