• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.180-185
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• 2006

Microwatt power level at relatively high voltage(order of volt) was produced by $Bi_{0.5}Sb_{1.5}Te_{3}/Bi_{2}Te_{2.4}Se_{0.6}$ thin film thermoelectric generators, and maximum output power varied with temperature difference in the square-law relation. Output voltage and current were possible to control by changing the way of electrical connection as well as the number of stacking plate-modules. Variation of open circuit voltage and short circuit current with temperature difference showed a linear relationship. There were, however, some differences in variations; open circuit voltage were dependent on the number of plate-module when connected in series, but it was not for parallel connection. On the other hand, short circuit current showed the opposite behavior to the case of open circuit current.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.186-186
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• 2013

Nitrogen doped Ge-Sb-Te (N-GST) thin films for phase change random access memory (PRAM) applications were investigated by synchrotron-radiation-based x-ray photoelectron spectroscopy and absorption spectroscopy. Nitrogen doping in GST resulted in more favorable N atoms' bonding with Ge atoms rather than with Sb and Te atoms [1,2], which explains the higher phase change transition temperature than that of undoped Ge-Sb-Te thin film. Surprisingly, it was noticed that N atoms also existed in the form of molecular nitrogen, $N_2$, which is detrimental to the stability of the GST performance [3]. N-doped GST experimental features were also supported by ab-initio molecular dynamic calculations [2]. References [1] M.-C. Jung, Y. M. Lee, H.-D. Kim, M. G. Kim, and H. J. Shin, K. H. Kim, S. A. Song, H. S. Jeong, C. H. Ko, and M. Han, "Ge nitride formation in N-doped amorphous Ge2Sb2Te5", Appl. Phys. Lett. 91, 083514 (2007). [2] Zhimei Sun, Jian Zhou, Hyun-Joon Shin, Andreas Blomqvist, and Rajeev Ahuja, "Stable nitride complex and molecular nitrogen in N doped amorphous Ge2Sb2Te5", Appl. Phys. Lett. 93, 241908 (2008). [3] Kihong Kim, Ju-Chul Park, Jae-Gwan Chung, and Se Ahn Song, Min-Cherl Jung, Young Mi Lee, Hyun-Joon Shin, Bongjin Kuh, Yongho Ha, Jin-Seo Noh, "Observation of molecular nitrogen in N-doped Ge2Sb2Te5", Appl. Phys. Lett. 89, 243520 (2006).

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.3080-3087
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• 2023

Thermoelectric (TE) materials working in radioisotope thermoelectric generators are irradiated by neutrons throughout its service; thus, investigating the neutron irradiation stability of TE devices is necessary. Herein, the influence of neutron irradiation with fluences of 4.56 × 10¹⁰ and 1 × 10¹³ n/cm² by pulsed neutron reactor on the electrical and thermal transport properties of n-type Bi₂Te_2.7Se_0.3 and p-type Bi_0.5Sb_1.5Te₃ thermoelectric alloys prepared by cold-pressing and molding is investigated. After neutron irradiation, the properties of thermoelectric materials fluctuate, which is related to the material type and irradiation fluence. Different from p-type thermoelectric materials, neutron irradiation has a positive effect on n-type Bi₂Te_2.7Se_0.3 materials. This result might be due to the increase of carrier mobility and the optimization of electrical conductivity. Afterward, the effects of p-type and n-type TE devices with different treatments on the output performance of TE devices are further discussed. The positive and negative effects caused by irradiation can cancel each other to a certain extent. For TE devices paired with p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te_2.7Se_0.3 thermoelectric legs, the generated power and conversion efficiency are stable after neutron irradiation.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.69-76
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• 1997

P-type ($Bi_{0.5}Sb_{1.5}Te_3$) and n-type ($Bi_2Te_{2.4} Se_{0.6}$) thermoelectric thin film were deposited on glass and Teflon substrates by the flash evaporation technique. The changes in thermoelectric properties, such as Seebeck coefficient, electrical conductivity, carrier concentration, carrier mobility, thermal conductivity, and figure of merit, were investigated as a function of film thickness and annealing condition. Figures of merit of the thin films annealed at 473 K for 1 hour were improved to be $1.3{\times}10^{-3}K^{-1}$ for p-type and $0.3{\times}10^{-3}K^{-1}$ for n-type, and they were almost independent of film thickness. Temperature sensors were fabricated from the thin films having the above mentioned properties. And thermo-emf, sensitivity, and time constant of the sensors were measured to evaluate their characteristics for temperature sensors. Thin film sensors deposited on Teflon substrates showed better performance than those on glass substrates, and their sensitivity and time constant were 2.91 V/W and 28.2 sec respectively for the sensor of leg width 1 mm$\times$length 16 mm.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.839-842
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• 2009

In this paper, chalcogenide glasses material(Se, Te, Sb) is firstly used as encapsulation layer of OLEDs under high vacuum of $10^{-4}$Pa. In the experiments, properties of OLEDs encapsulated by Se, Te, Sb thin film is compared with that of device encapsulated by traditional method. It is found that Se, Te, Sb film can extend lifetime of devices to 1.4, 2, 1.3 times respectively. Chalcogenide glasses film as encapsulation layer has little effect on some characteristics of device. The research indicated that OLEDs can be well protected upon applying Se, Te, Sb film as encapsulation layer. It is clear that it can prolong the lifetime obviously.

• Journal of the Korean Institute of Telematics and Electronics
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• v.5 no.3
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• pp.1-8
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• 1968

This thermcelectrie generator devices have been determined for bismuth alloys, Sb2T and AnSb containing small amounts of doping materials. The thermoeleotric matermoelectric power;$\alpha$; resistivity; $\rho$, heatconduction; k, and temperature difference between cold and hot junction was measured. Generator consisting both B T + B S and B T+S T is better efficient than others containing another thermoceuple matarials. Its efficiency is 1.42%.

• Korean Journal of Materials Research
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• v.6 no.7
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• pp.678-683
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• 1996

In the fabrication processes of thin film thermoelectrics, a subsequent annealing treatment is inevitable to reduce the defects and residual stresses introduced during the film growth, and to make the uniform carrier concentration of the film. However, the diffusion-induced atomic redistribution and the broadening of p/n junction region are expected to affect the thermoelectric properties of thin film modules. The present study intends to investigate the diffusion at the p/n junctions of thermoelectric thin films and to relate it to the property changes. The film junctions of p-type(Bi0.5Sb1.5Te3)and n-type(Bi2Te2.4Se0.6)were prepared by the flash evaporation method. Aluminum thin layer was employed as a diffusion barrier between p-and n-type films of the junction. This was found to be an effective barrier by showing a negligible diffusion into both type films. After annealing treatment, the thermoelectric properties of p/n couples with aluminum barrier layer were accordingly retained their properties without any deterioration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.166-166
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• 2007

PRAM (phase-change random access memory)은 전류 펄스 인가에 따른 기록매질의 비정질-결정질 간 상변화와 그에 동반되는 저항변화를 이용하는 차세대 비휘발성 메모리 소자로서 연구되어지고 있다. 본 논문에서는 $(Ge_2Sb_2Te_5)_{1-x}Se_x$ (x=0,0.05,0.1,0.15) 조성에 대한 벌크 및 박막시료를 제작하고 각 조성에 대한 상변화 특성을 분석하였다. XRD를 통해 열처리 온도에 따른 구조적 분석을 실시하였고 UV-Vis-IR spectrophotometer를 사용하여 박막의 광학적 특성을 분석하였다. 또한 각 조성의 결정화 속도를 비교하기 위해 static tester를 사용하여 레이저 펄스 시간에 대한 반사도 변화를 측정하였고 DSC를 통해 결정화 온도를 측정하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1287-1288
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• 2008

In the past work, we showed that $Ge_1Se_1Te_2$ thin films provide a promising alternative for PRAM applications to overcome the problems of conventional $Ge_2Sb_2Te_5$ PRAM devices. However, $Ge_1Se_1Te_2$ thin films were unstable at SET and RESET process. Because of unstable state and its melting temperature, we alloyed As for 5wt%, 10wt% and 15wt% respectively. The phase transition temperature of $Ge_1Se_1Te_2$-only thin film is found to be 213$^{\circ}C$ while As 10wt% alloyed $Ge_1Se_1Te_2$ showed phase transition at 242$^{\circ}C$ with more stability.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.32-33
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• 2006

As next generation nonvolatile memory, chalcogenide-based phase change memory can substitute for a conventional flash memory from its high performance. Also, fast writing speed, low writing voltage, high sensing margin, low power consumption and repetition reliability over $10^{15}$ cycle shows its possibility. At our laboratory, we invented ${Ge_1}{Se_1}{Te_2}$ material to alternate with conventional ${Ge_2}{Sb_2}{Te_5}$ for improve its ability. We respect the ${Ge_1}{Se_1}{Te_2}$ material can be a solution for high power consumption problem and long time at 'set' performance. A conductivity experiment from variable temperature was performed to see reliability of repetition at read and write performance. Compare with conventional ${Ge_2}{Sb_2}{Te_5}$ material, these two materials are used as complex compound to get the finest parameter.