• 한국전기전자재료학회논문지
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• 제14권10호
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• pp.792-795
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• 2001

we present a electrical transport(resistivity, Hall effect) measurements in varying temperature ranges between 78K and 300K on HoSi$_2$ composites by hot-pressed sintering. It has been found that this sintered HoSi$_2$ has a orthorhombic structure, and lattices constant is a=9.8545$\AA$, b=7.7935$\AA$, c=7.8071$\AA$. The measured electrical resistivity is about 1.608$\Omega$ cm and carrier mobility is about 6.9$\times$10$^{1}$cm $^{2}$V.sec at low room temperature. The Hall effect shows a n-type conductivity in the sintered HoSi$_2$.

• 한국초전도ㆍ저온공학회논문지
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• 제15권1호
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• pp.6-10
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• 2013

We investigate the electrical and thermal transport properties of a sesquicarbide superconductor $La_2C_3$, including electrical resistivity, thermoelectric power, and thermal conductivity. The electrical resistivity exhibits a typical metallic character with a saturation behavior at high temperatures. The thermoelectric power shows a metallic behavior with pronounced phonon-drag effect, comparable with pure metals. The broad peak of the thermal conductivity is observed in the superconducting state, which is rapidly suppressed by magnetic fields. These observations suggest that the electron-phonon scattering is significant in $La_2C_3$, which is relevant with the relatively high-$T_c$ in $La_2C_3$ through strong electron-phonon coupling with low frequency phonon modes.

• 지구물리와물리탐사
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• 제10권4호
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• pp.361-368
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• 2007

본 논문은 지표 및 시추공 전기 전자탐사 결과의 정량적인 해석을 위하여 해안 지하수의 전기비저항과 등가 NaCl 염분도와의 관계식을 제안하였다. 해안에서 10 km 이내에 위치하고 전기전도도가 1,000 ${\mu}S/cm$ 이상인 38개의 지하수 시료에 대한 수리지구화학 분석 결과를 이용하여 전기비저항과 등가 NaCl 염분도와의 관계식을 유도하였다. 수리지구 화학분석 결과의 등가 NaCl 염분도 환산은 Schlumberger 도표 GEN-8을 이용하였으며 전기전도도는 현장에서 휴대용 장비로 측정하였다. 본 논문에서 해안 지하수의 수리지구화학분석 결과를 이용하여 제안한 해안 지하수의 전기비저항$(R_w)$ 과 등가 NaCl 염분도(Eq_NaCl)와의 관계식은 Eq_NaCl=$5935.3551{\times}R_w^{-1.0993}$이며 전기전도도(EC)와 용존고형물총량(TDS)과의 관계식은 TDS=0.721${times}$EC와 같다. 해안대수층 지하수의 전기비저항과 등가 NaCl 염분도 및 TDS와의 관계식은 서 남해 해안지역의 해수침투 평가에 유용하게 이용될 것으로 판단된다.

• The Korean Journal of Ceramics
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• 제3권2호
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• pp.92-95
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• 1997

Because of the novel characteristics such as chemical stability, hardness, electrical resistivity and thermal conductivity, diamond-like carbon (DLC) film is a suitable material for the passivation layers. For this purpose, using the PECVD, DLC films were synthesized at room temperature. The adhesion and the hardness of the DLC films deposited on Si an SiO2 substrate were measured. The resistivity of 5.3$\times$$10^8$$\Omega$.cm was measured by automatic spreading resistance probe analysis method. The thermal conductivities of different DLC films were measured and compared with that of phospho silicate glass (PSG) film which is commonly used as passivation layers. The thermal conductivity of DLC film was improved by increasing hydrogen flow rate up to 90 sccm and was better than that of PSG film. The patterning techniques of the DLC film developed using the RIE and the lift-off method to form 5$\mu\textrm{m}$ line. Finally, the thermal characteristics of the power transistor with the DLC film as passiviation layer was analyzed.

• 한국재료학회지
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• 제16권9호
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• pp.529-532
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• 2006

Sn-filled $Co_8Sb_{24}$ skutterudites were synthesized by the encapsulated induction melting process. Single ${\delta}-phase$ was successfully obtained by subsequent annealing and confirmed by X-ray diffraction analysis. Temperature dependences of Seebeck coefficient, electrical resistivity and thermal conductivity were examined from 300 K to 700 K. The positive Seebeck coefficient confirmed the p-type conductivity of the Sn-filled $Co_8Sb_{24}$. Electrical resistivity increased with increasing temperature, which shows that the Sn-filled $Co_8Sb_{24}$ skutterudite is a highly degenerate semiconductor. Thermal conductivity was reduced by Sn-filling because the filler atoms acted as phonon scattering centers in the skutterudite lattice. Thermoelectric figure of merit was enhanced by Sn filling and its optimum filling content was considered to be $z{\leq}0.5$ in the $Sn_zCo_8Sb_{24}$ system.

• 한국분말재료학회지
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• 제17권2호
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• pp.136-141
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• 2010

Bismuth-telluride based $(Bi_{0.2}Sb_{0.8})_2Te_3$ thermoelectric powders were fabricated by two-step planetary milling process which produces bimodal size distribution ranging $400\;nm\;{\sim}\;2\;{\mu}m$. The powders were reduced in hydrogen atmosphere to minimize oxygen contents which cause degradation of thermoelectric performance by decreasing electrical conductivity. Oxygen contents were decreased from 0.48% to 0.25% by the reduction process. In this study, both the as-synthesized and the reduced powders were consolidated by the spark plasma sintering process at $350^{\circ}C$ for 10 min at the heating rate of $100^{\circ}C/min$ and then their thermoelectric properties were investigated. The sintered samples using the reduced p-type thermoelectric powders show 15% lower specific electrical resistivity ($0.8\;m{\Omega}{\cdot}cm$) than those of the as-synthesized powders while Seebeck coefficient and thermal conductivity do not change a lot. The results confirmed that ZT value of thermoelectric performance at room temperature was improved by 15% due to high electric conductivity caused by the controlled oxygen contents present at bismuth telluride materials.

• 한국세라믹학회지
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• 제31권12호
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• pp.1529-1535
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• 1994

Electrical conduction mechanisms of RuO2-based thick film resistors were investigated with frequency depandence on AC conductivity. Electrical conduction mechanisms of lower resistivity system (100{{{{ OMEGA }}/sq) sintered at 600~90$0^{\circ}C$ were all metallic conduction mechanism. In case of higher resistivity (10K{{{{ OMEGA }}/sq) system, the electrical conduction mechanisms were very depenent on sintering temperature. When sintering temperature was $600^{\circ}C$, the electrical conduction mechamism was ionic, and as increasing the sintering temperature, the electrical conduction mechanism was changed from ionic to hopping conduction mechanism.

• 한국재료학회지
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• 제28권4호
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• pp.241-246
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• 2018

$TaN_x$ film is grown by plasma enhanced atomic layer deposition (PEALD) using t-butylimido tris(dimethylamido) tantalum as a metalorganic source with various reactive gas species, such as $N_2+H_2$ mixed gas, $NH_3$, and $H_2$. Although the pulse sequence and duration are the same, aspects of the film growth rate, microstructure, crystallinity, and electrical resistivity are quite different according to the reactive gas. Crystallized and relatively conductive film with a higher growth rate is acquired using $NH_3$ as a reactive gas while amorphous and resistive film with a lower growth rate is achieved using $N_2+H_2$ mixed gas. To examine the relationship between the chemical properties and resistivity of the film, X-ray photoelectron spectroscopy (XPS) is conducted on the ALD-grown $TaN_x$ film with $N_2+H_2$ mixed gas, $NH_3$, and $H_2$. For a comparison, reactive sputter-grown $TaN_x$ film with $N_2$ is also studied. The results reveal that ALD-grown $TaN_x$ films with $NH_3$ and $H_2$ include a metallic Ta-N bond, which results in the film's higher conductivity. Meanwhile, ALD-grown $TaN_x$ film with a $N_2+H_2$ mixed gas or sputtergrown $TaN_x$ film with $N_2$ gas mainly contains a semiconducting $Ta_3N_5$ bond. Such a different portion of Ta-N and $Ta_3N_5$ bond determins the resistivity of the film. Reaction mechanisms are considered by means of the chemistry of the Ta precursor and reactive gas species.

• 한국재료학회지
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• 제11권4호
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• pp.312-318
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• 2001

다발체 형성과 인발 공정으로 제조된 Cu-Nb 필라멘트 미세복합재료의 기계적 전기적 특성에 대하여 연구하였다. Nb의 함량이 증가함에 따라 강도는 점차 증가하였으나 연성은 Nb의 함량에 무관하였다. 293K와 75K에서의 항복강도의 비율은 Cu-Nb 미세복합재료의 Young의 계수 비율과 비슷하게 관찰되었다. 이러한 사실은 주로 장범위 방해물(athermal obstacles)들이 Cu-Nb 마세복합재료의 강도에 영향을 미친다는 것을 의미한다. 파면 조직관찰 결과는 Cu-Nb 미세복합재료는 Nb의 함량에 판관계없이 연성파괴의 특성을 나타내었으며, 부전선재 (subelematal wires)사이의 계면을 따라 발생하는 2차크랙 (secondary crack) 의 양은 Nb 함량이 증가함에 따라 증가하였다. 전기 전도도와 비저항비 (${\rho}_{293k}/{rho}_{75k}$)는 Nb 함량이 증가할수록 감소하였다. 이와 같은 Nb함량에 따른 전기전도도와 비저항비의 감소는 계면산란의 기여도가 증가하였기 때문이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1916-1918
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• 1999

The electrical conductive mechanism and temperature dependence of electrical resistivity of ${\beta}-SiC+ZrB_2$ composites with $Al_2O_3+Y_2O_3$ contents were investigated. The electrical resistivity of hot-pressed composites was measured by the Pauw method from $25^{\circ}C$ to $700^{\circ}C$. The electrical resistivity of the composites showed the PTCR(Positive Temperature Coefficient Resistivity) and follow the electrical conduction model for a homogeneous mixture of two kind of particles with different conductivity. Also, the electrical resistivity versus temperature curves indicate the formation of local chains of $ZrB_2$ particles.