• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.300-300
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• 2007

• Journal of the Korean Ceramic Society
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• v.37 no.7
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• pp.651-651
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• 2000

• Proceedings of the Korean Magnestics Society Conference
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• 2005.06a
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• pp.72-73
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• 2005

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.686-687
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• 2006

The encapsulated induction melting and hot pressing were employed to prepare Fe-doped $CoSb_3$ skutterudites and their thermoelectric properties were investigated. Single phase $\delta-CoSb_3$ was successfully obtained by the subsequent heat treatment at 773K for 24 hours. Iron atoms acted as electron acceptors by substituting cobalt atoms. Thermoelectric properties were remarkably improved by the appropriate doping. $Co_{0.7}Fe_{0.3}Sb_3$ was found as an optimum composition for best thermoelectric properties in this work.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1329-1330
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• 2007

Phase-change random access memory(PRAM) has many advantages compare with the existing memory. For example, fast programming speed, low programming voltage, high sensing margin, low power consume and long cyclability of read/write. Though it has many advantages, there are some points which must be improved. So, we invented and studied new constitution of $Ge_{1}Se_{1}Te_{2}$ chalcogenide material. Actually, the performance properties have been improved surprisingly. However, crystallization time was as long as ever for amorphization time. In this paper, we studied in order to make set operation time and reset operation voltage reduced. In the present work, by alloying Sb in $Ge_{1}Se_{1}Te_{2}$. we could confirm that improved its set operation time and reset operation voltage. As a result, the method of Sb-alloyed $Ge_{1}Se_{1}Te_{2}$ can be solution to decrease the set operation time and reset operation voltage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.8
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• pp.658-666
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• 2000

Sb and Sb-Fe doped SnO$_2$film resistors were prepared by spray pyrolysis technique. The effects of Sb and Sb-Fe addition on TCR and electrical properties of SnO$_2$film resistors were studied. Also the dependence of electrical properties on the substrate temperature and substrate-nozzle distance was investigated. The Sn-Sb system with 7.9 mol% SbCl$_3$(STO-406) and Sn-Sb-Fe systems with 7.3 mol% SbCl$_3$+7.3 mol% FeCl$_3$(STO-407) and with 3.4 mol% SbCl$_3$+7.7mol% FeCl$_3$(STO-408) were prepared. Both of the systems Sn-Sb and Sn-Sb-Fe represented nonlinearity of TCR with temperature. As the amount of Fe increased TCR was shifted to positive direction. Decreasing Sb or increasing Fe caused resistivity to increase. Also increasing Fe caused the crystallization degree of rutile structure in SnO$_2$film to decrease. The electrical resistivity decreased with increasing substrate temperature The resistivity decreased with increasing substrate-nozzle distance in the ranges from 15 to 25 cm and increased rapidly at the distance over 25cm.

• Journal of Sensor Science and Technology
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• v.6 no.6
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• pp.476-482
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• 1997

A portable electronic nose system has been fabricated and characterized using an oxide semiconductor gas sensor array and pattern recognition techniques such as principal component analysis and back-propagation artificial neural network. The sensor array consists of six thick-film gas sensors whose sensing layers are Pd-doped $WO_{3}$, Pt-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$ + Pd coated layer, $Al_{2}O_{3}$-doped ZnO and $PdCl_{2}$-doped $SnO_{2}$. The portable electronic nose system consists of an 16bit Intel 80c196kc as CPU, an EPROM for storing system main program, an EEPROM for containing optimized connection weights of artificial neural network, an LCD for displaying gas concentrations. As an application the system has been used to identify 26 carbon monoxide/hydrocarbon (CO/HC) car exhausting gases in the concentration range of CO 0%/HC 0 ppm to CO 7.6%/HC 400 ppm and the identification has been successfully demonstrated.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.55-55
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• 2011

질소 등을 GST225 상변화재료에 첨가시켜 비저항을 증가시킴으로서 PCRAM의 동작 전류를 감소시킨 연구가 선행된 바 있다. 본 연구에서는 GST225와 달리 고속 동작 특성을 갖는 것으로 널리 알려진 Ge-doped SbTe (GeST) 상변화 재료에 Carbon을 첨가하여 박막 특성을 연구하여 동작 전류 감소의 가능성을 타진하였다. 실험을 위한 박막 제작을 위해 2 inch size의 GeST 및 C doped GeST (C-GeST) single target을 이용하여 RF magnetron co-sputtering 하였다. 박막은 carbon이 첨가되지 않은 GeST와 carbon 첨가량이 늘어나는 순서로 C-GeST 1, C-GeST 2, C-GeST 3로 구성된다. 이 때 제작한 박막의 composition analysis를 위해 XRF/RBS/AES가 사용되었고 제작된 박막의 기본적인 특성평가를 위해 resistivity(${\rho}$)와 crystallzation temp.(Cx), surface morphology(AFM), x-ray diffraction pattern(XRD)를 측정하였다. 실험결과 GeST, C-GeST 1, C-GeST 2, C-GeST 3 박막의 Cx는 각각 209, 225, 233, $245^{\circ}C$로 측정되어 carbon 첨가량이 증가됨에 따라 결정화 온도가 증가되는 것을 알 수 있었다. 또한 ${\rho}$도 마찬가지로 annealing 온도를 약 $320^{\circ}C$로 할 경우 ${\rho}$(as-dep)와 ${\rho}$(crystalline) 모두 0.03 / $2.61*10^{-6}$, 0.08 / $7.93*10^{-6}$, 0.09 / $11.99*10^{-6}$, 0.13 / $13.49*10^{-6}{\Omega}{\cdot}m$로 증가하였다. 증가된 ${\rho}$의 원인이 박막의 grain size의 감소라고 단언 할 수는 없으나 AFM 측정결과 grain이라고 추측되는 박막 feature들의 size가 점차 감소하는 것을 확인하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.814-820
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• 2009

Antimony (Sb) doped ZnO thin films (0.1 at.%) were deposited on sapphire (0001) substrates at various temperatures (200 - 600$^{\circ}C$) by using pulsed laser deposition technique. All the thin films have been characterized by X-ray diffractometer, atomic force microscopy and spectrophotometer to investigate their structural, morphological and optical properties, respectively. Hall measurements were also carried out to identify the electrical properties of the thin films. These thin films were constituted in wurtzite structure with the preferential orientation of (002) diffraction plane and had as high as 80% optical transmission in the visible range. The bandgap energy also was determined by spectrophotometer which was around 3.28 eV. Hall measurements results revealed that the Sb dope ZnO thin film (0.1 at.%) grown at $500^{\circ}C$ exhibited p-type conduction with a carrier concentration of $8.633\times10^{16}\;cm^{-3}$, a mobility of $1.41\;cm^2/V{\cdot}s$ and a resistivity of $51.8\;\Omega{\cdot}cm$. We have successfully achieved p-type conduction in antimony doped ZnO thin films with low doping level even though the electrical properties are not favorable. This paper suggests the feasibility of p-type doping with large-size-mismatched dopant by using pulsed laser deposition.

• Korean Journal of Materials Research
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• v.9 no.5
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• pp.520-527
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• 1999

As a new approache(extrusion-sintering process) to fabricate the thermoelectric materials, it has been at tempted to extrude and sinter the powders simultaneously. It was possible to produce the highly dense <$(Bi,Sb)_2(Te,Se)_3$-based thermoelectrics with sound surface appearances and microstructures by adjusting the process variables. For the p-type materials, the Seeback coefficient was increased with the amount of Te dopants, and the thermoelectric figure of merit appeared to be $2.5\times10^{-3}/K$ at room temperature when doped with 3 at % Te. The n-type specimen doped with 0.16 mol% $SbI_3$ showed the thermoelectric figure of merit of $1.8\times10^{-3}/K$. In both p-type an 우-type materials, the carrier mobility an the thermoelectric figure of merit parallel to the extrusion direction were higher than those perpendicular to it.