• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.100-100
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.35-35
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• 2005

• 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.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1084-1085
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• 2006

We studied formation of nanostructured $TiB_2$-Cu composites under shock wave conditions. We investigated the influence of preliminary mechanical activation (MA) of Ti-B-Cu powder mixtures on the peculiarities of the reaction between Ti and B under shock wave. In the MA-ed mixture the reaction proceeded completely while in the non-activated mixture the reagents remained along with the product . titanium diboride. The size of titanium diboride particles in the central part of the compact was 100-300 nm.

• Journal of Sensor Science and Technology
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• v.17 no.5
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• pp.361-368
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• 2008

Nanosized $SnO_2$ particles were synthesized by homogeneous precipitation method using tin chloride ($SnCl_4{\cdot}5H_{2}O$) and urea ($CO(NH_2)_2$). The powders were heated at $500^{\circ}C$ and $600^{\circ}C$ for 2h. The crystal structure, microstructure, thermal behavior, specific surface area were analyzed using XRD, FE-SEM, TGA and BET, respectively. The initial resistance and the $H_2$ sensing properties were measured as a function of ${Sb_2}{O_3}$ and Pd doping concentrations. The resistance was decreased with the addition of ${Sb_2}{O_3}$ and the sensitivity for $H_2$ gas was increased with the addition of Pd. Thus, the optimum $H_2$ gas sensing property was obtained in the 0.25.mol% ${Sb_2}{O_3}$ and 1.w% added $SnO_2$ powders.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.80-81
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• 2005

Chalcogenide phase change memory has high performance to be next generation memory, because it is a nonvolatile memory processing high programming speed, low programming voltage, high sensing margin, low consumption and long cycle duration. We have developed a sample of PRAM with thermal protected layer. We have investigated the phase transition behaviors in function of process factor including thermal protect layer. As a result, we have observed that set voltage and duration of protect layer are more improved than no protect layer.

• Korean Journal of Materials Research
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• v.15 no.2
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• pp.93-96
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• 2005

The arc melting was employed to prepare undoped $CoSb_3$ compounds and their thermoelectric properties were investigated. Specimen annealed at $400^{\circ}C$ for 24 hrs showed sound microstructure. However, considerable voids and cracks were found after annealing at above $500^{\circ}C$. It seems to be attributed to the phase dissociation and thermal expansion due to phase transitions during annealing and cooling. Single phase $\delta-CoSb_3$ was successfully obtained by annealing at $400^{\circ}C$ for 24 hrs. In the case of increasing annealing temperature, phase decompositions occurred. Undoped $CoSb_3$ showed p-type conduction and intrinsic semiconducting behavior at all temperatures examined. Thermoelectric properties were remarkably improved by annealing and they were closely related to phase transitions.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.28.2-28.2
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• 2009

군사적, 산업적 용도로 널리 활용되고 있는 적외선 검출기는 InSb, HgCdTe(MCT)와 같은 물질들을 감지 소자로 사용하고 있다. 현재 가장 많이 사용되는 MCT는 적외선의 전 영역을 감지할 수 있는 장점이 있지만, 대면적 제작이 어려운 단점이 있다. 이에 비해 InSb는 안정적인 재료의 특성, 높은 전하이동도($1.2\times10^6\;cm^2/Vs$) 그리고 대면적 소자 제작의 가능성 등이 높게 평가되어 차세대 적외선 검출소자로 각광 받고 있다. InSb 적외선 수광 소자는 1970년대부터 미국을 중심으로 이온주입, MOCVD 또는 MBE와 같은 다양한 공정을 이용하여 제작되어 왔으며, 앞으로도 군수용 제품을 비롯하여 산업전반에서 더욱 각광을 받을 것으로 예상된다. 하지만 InSb는 77 K에서 0.225 eV의 상대적으로 작은 밴드갭을 갖고 있기 때문에 누설전류로 인한 성능저하가 고질적인 문제로 대두되었고, 이를 해결하기 위한 고품질 절연막 연구가 InSb 적외선 수광 소자 연구의 주요 이슈 중 하나가 되어왔다. PECVD, photo-CVD, anodic oxidation 등의 공정을 이용하여 $SiO_2$, $Si_3N_4$, 양극산화막(anodic oxide) 등 다양한 물질들에 대한 연구가 진행되었고[1,2], 산화막과 반도체 계면에서의 열확산을 억제하여 계면트랩밀도를 최소화하기 위한 연구도 활발히 이루어졌다[3]. 하지만 InSb 소자의 성능개선을 위한 최적화된 산화막에 대한 연구는 여전히 불충분한 실정이다. 본 연구에서는 n형 (100) InSb 기판 (n = 0.2 ~ $0.85\times10^{15}cm^{-3}$ @ 77 K)을 이용하여 양극산화막, $SiO_2$, $Si_3N_4$ 등을 증착하고 절연막으로서 이들의 특성을 비교 분석하였다. 양극산화막은 상온에서 1 N KOH 용액을 이용하여 양극산화법으로 증착하였으며, $SiO_2$, $Si_3N_4$는 PECVD로 $150^{\circ}C$에서 $300^{\circ}C$까지 온도를 변화시켜가며 증착하였다. SEM분석과 XPS분석으로 두께의 균일도와 절연막의 조성, 계면확산 정도를 확인하였으며, I-V와 C-V 커브측정을 통해 각 절연막의 전기적 특성을 평가하였다. 이 분석들을 통해 각각의 공정 조건에 따른 절연막의 상태를 전기적 특성과 관련지어 설명할 수 있었다.

• Journal of Electrochemical Science and Technology
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• v.11 no.2
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• pp.165-171
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• 2020

The electrochemical preparation and spectroscopic characterisation of iridium-antimony (Ir-Sb) species is important owing to their potential applications as nanostructure materials. Nanostructures, i.e. nanoflower and nanodisk, of Ir-Sb were electrodeposited on conductive substrates using a practical electrochemical method based on the simultaneous underpotential deposition (UPD) of Ir and Sb from the IrCl₃ and Sb₂O₃ at a constant potential. Electrochemical UPD mechanism of Ir-Sb was studied using cyclic voltammetry and potential-controlled electrochemical deposition techniques. Herein, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron and Raman spectroscopy were used to determine the morphological and structural properties of the electrochemically-synthesised Ir-Sb nanostructures.

• Journal of Sensor Science and Technology
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• v.20 no.1
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• pp.1-7
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• 2011

Undoped and Sb-doped $SnO_2$ nanofibers were prepared by electrospinning and their responses to $H_2$, CO, $CH_4$, $C_3H_8$, and $C_2H_5OH$ were measured. In the undoped $SnO_2$ nanofibers, the gas response ($R_a/R_g$, $R_a$: resistance in air, $R_g$: resistance in gas) to 100 ppm $C_2H_5OH$ was very high(33.9), while that to the other gases ranged from 1.6 to 2.2. By doping with 2.65 wt% Sb, the response to 100 ppm $C_2H_5OH$ was decreased to 4.5, whereas the response to $H_2$ was increased to 3.0. This demonstrates the possibility of detecting a high $H_2$ concentration with minimum interference from $C_2H_5OH$ and the potential to control the gas selectivity by Sb doping.