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1.
Jennifer Graff Song Zhu Tim Holgate Jiangying Peng Jian He Terry M. Tritt 《Journal of Electronic Materials》2011,40(5):696-701
Void-filling in the CoSb3 skutterudite lattice with different kinds of heavy elements has proven to be an effective mechanism to enhance thermoelectric
performance due primarily to a reduction in lattice thermal conductivity. Specifically, our findings on the series In
x
Yb
y
Co4Sb12 [0 ≤ (x, y) ≤ 0.2] have further motivated an attempt to form triple-filled skutterudites Ce0.1In
x
Yb
y
Co4Sb12 with In and Yb concentrations [0 ≤ (x, y) ≤ 0.2] and with the Ce concentration held constant (Ce0.1). All of these samples have been prepared via a simplified melting–annealing–sintering procedure and were first characterized
by means of x-ray powder diffraction and scanning electron microscopy, followed by measurements of the Hall coefficient, electrical
and thermal conductivities, and Seebeck coefficient. Our aim is to further elucidate the roles of the three elements (Ce,
In, and Yb) in these materials. Compared with the addition of just In or Yb, we found that simultaneous addition of both In
and Yb reduced the lattice thermal conductivity without significantly degrading the power factor. Further addition of the
third element (Ce), along with In and Yb, also produced a similar result. However, we noticed that some of the In and Yb were
also observed in the form of secondary phases (InSb and Yb2O3), not entering entirely as filler atoms. As a result of our investigation, several compositions achieved increased sustainability
and enhanced thermoelectric performance, with maximum ZT values of about 1.3 to 1.4 obtained at around 800 K. 相似文献
2.
Kwan-Ho Park Jae-Yong Jung Soon-Chul Ur Il-Ho Kim 《Journal of Electronic Materials》2010,39(9):1750-1754
The thermoelectric properties of In-filled and Fe-doped CoSb3 (In
z
Co4−x
- Fe
x
Sb12) skutterudites prepared by encapsulated induction melting were examined. A single δ-phase was obtained successfully by subsequent
annealing at 823 K for 120 h. The Hall and Seebeck coefficients of the In
z
Co4−x
Fe
x
Sb12 samples had positive signs, indicating p-type conduction. The electrical conductivity was increased by Fe doping, and the thermal conductivity was decreased by In
filling due to phonon scattering. The thermoelectric properties were improved by In filling and Fe doping, and were closely
related to the optimum carrier concentration and phonon scattering. 相似文献
3.
4.
Guanghe Li Ken Kurosaki Yuji Ohishi Hiroaki Muta Shinsuke Yamanaka 《Journal of Electronic Materials》2013,42(7):1463-1468
The high-temperature thermoelectric properties of In x Co4Sb12 (0.05 ≤ x ≤ 0.40) skutterudite compounds were investigated in this study. The phase states of the samples were identified by x-ray diffraction analysis and field-emission scanning electron microscopy at room temperature. InSb and CoSb2 were found as secondary phases in samples with x = 0.10 to 0.40. The filling limit of In into the CoSb3 cages of In x Co4Sb12 was in the range 0.05 < x < 0.10. The electrical resistivity, Seebeck coefficient, and thermal conductivity of the In x Co4Sb12 samples were measured from room temperature to 773 K. The Seebeck coefficient of all samples was negative. Reduction of the thermal conductivity by In addition resulted in a high thermoelectric figure of merit (ZT) of 0.67 for In0.35Co4Sb12 at 600 K. 相似文献
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7.
Nathan J. Takas Pranati Sahoo Dinesh Misra Hongfang Zhao Nathaniel L. Henderson Kevin Stokes Pierre F.P. Poudeu 《Journal of Electronic Materials》2011,40(5):662-669
A series of samples with the composition Zr0.5Hf0.5Co1−x
Ir
x
Sb0.99Sn0.01 (x = 0.0 to 0.7) were synthesized by high-temperature solid-state reaction at 1173 K. High-density pellets of the powders were
obtained using hot press (HP) and spark plasma sintering (SPS) techniques. The thermoelectric properties of the pellets were
measured from 300 K to 750 K. Independently of the pressing conditions, all Ir-containing samples (x > 0) showed p-type semiconducting behavior. At 300 K, the electrical conductivity and thermopower of Zr0.5Hf0.5Co1−x
Ir
x
Sb0.99Sn0.01 materials surprisingly increased with increasing Ir concentration. The largest electrical conductivity and thermopower values
of 150 S/cm and 140 μV/K, respectively, were observed at 300 K for x = 0.7. The thermal conductivity of the synthesized materials decreased with increasing Ir content, went through a minimum
value (x = 0.3), and increased thereafter with further addition of Ir. Pellets fabricated by SPS showed smaller thermal conductivity
than pellets of the same composition obtained from uniaxial hot pressing. A thermal conductivity value of ∼2.0 W/m K was observed
at 300 K for an SPS pellet with the com- position Zr0.5Hf0.5Co0.5Ir0.5Sb0.99Sn0.01. The thermal conductivity of Zr0.5Hf0.5- Co1−x
Ir
x
Sb0.99Sn0.01 decreased with rising temperature, and the smallest value of ∼1.5 W/m K was observed at 750 K for the SPS specimen with x = 0.5. 相似文献
8.
S. H. Yang T. J. Zhu S. N. Zhang J. J. Shen X. B. Zhao 《Journal of Electronic Materials》2010,39(9):2127-2131
Thermoelectric (TE) materials (GeTe)80(Ag
y
Sb2−y
Te3−y
)20 (y = 0.6, 0.8, 1.0, 1.2, and 1.4) were prepared, and their TE properties and microstructure studied in this work. Due to their
relatively low thermal conductivity and proper carrier concentration, high ZT values were obtained for all samples except for y = 1.4. Using transmission electron microscopy, twins, antiphase domains, and low-angle grain boundaries were observed throughout
the sample with y = 1.2. Nanoscale regions with double atomic spacing were detected. These regions and the matrix were coherent without obvious
mismatch. The relationship between high ZT values and microstructure is discussed. 相似文献
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11.
Kwan-Ho Park Il-Ho Kim Soon-Mok Choi Won-Seon Seo Dong-Ik Cheong Hyung Kang 《Journal of Electronic Materials》2013,42(7):1377-1381
p-Type Yb z Fe4?x Co x Sb12 skutterudites were prepared by encapsulated melting and hot pressing, and the filling and doping (charge compensation) effects on the transport and thermoelectric properties were examined. The electrical conductivity of all specimens decreased slightly with increasing temperature, indicating that they were in a degenerate state due to high carrier concentrations of 1020 cm?3 to 1021 cm?3. The Hall and Seebeck coefficients exhibited positive signs, indicating that the majority carriers are holes (p-type). The Seebeck coefficient increased with increasing temperature to maximum values of 100 μV/K to 150 μV/K at 823 K. The electrical and thermal conductivities were reduced by substitution of Co for Fe, which was responsible for the decreased carrier concentration. Overall, the Yb-filled Fe-rich skutterudites showed better thermoelectric performance than the Yb-filled Co-rich skutterudites. 相似文献
12.
Double-filled skutterudites In x Pr y Co4Sb12, which are currently being investigated for potential applications as thermoelectric materials, have been successfully prepared by inductive melting and annealing. Our results showed that In and Pr double filling effectively improves both electrical conductivity and Seebeck coefficient compared with pristine or single-filled CoSb3, giving rise to a respectable power factor. The largest power factor, 2.33 m Wm?1 K?2, was achieved at 609 K for In0.05Pr0.05Co4Sb12; this value is approximately three times that for In x Co4Sb12 (x ≤ 0.3) skutterudites. These results imply that In and Pr double filling are better than In single filling for efficient improvement of the thermoelectric properties of CoSb3 skutterudite. 相似文献
13.
Polycrystalline samples of the RuSb2Te ternary skutterudite compound were prepared by the powder metallurgy method, and the influence of various types of doping on its thermoelectric properties was studied. The phase purity of the prepared samples was checked by means of powder x-ray diffraction, and their compositions were checked by electron probe x-ray microanalysis. Hot-pressed p-type samples were characterized by measurements of electrical conductivity, Hall coefficient, Seebeck coefficient, and thermal conductivity. Various doping strategies, i.e., cation substitution (Ru0.95Fe0.05Sb2Te), anion substitution (RuSb2Sn0.1Te0.9) or partial filling of voids of the ternary skutterudite structure (Yb0.05RuSb2Te), were investigated, and the influence of the dopants on the changes of the resulting transport, thermoelectric, and thermal properties is described. 相似文献
14.
Huiyuan Geng Takahiro Ochi Shogo Suzuki Masaaki Kikuchi Satoru Ito Junqing Guo 《Journal of Electronic Materials》2013,42(7):1999-2005
Bulk multifilled n- and p-type skutterudites with La as the main filler were fabricated using the spark plasma sintering (SPS) method. The thermoelectric properties and thermal stability of these skutterudites were investigated. It was found that the interactions among the filling atoms also play a vital role in reducing the lattice thermal conductivity of the multifilled skutterudites. ZT = 0.76 for p-type La0.8Ba0.01Ga0.1Ti0.1Fe3CoSb12 and ZT = 1.0 for n-type La0.3Ca0.1Al0.1Ga0.1In0.2Co3.75Fe0.25Sb12 skutterudites have been achieved. Furthermore, the differential scanning calorimetry (DSC) results show that there is no skutterudite phase decomposition till 750°C for the La0.8Ba0.01Ga0.1Ti0.1Fe3CoSb12 sample. The thermal stability of the La0.8Ba0.01Ga0.1Ti0.1Fe3CoSb12 skutterudite is greatly improved. Using the developed multifilled skutterudites, the fabricated module with size of 50 mm × 50 mm × 7.6 mm possesses maximum output power of 32 W under the condition of hot/cold sides = 600°C/50°C. 相似文献
15.
Single-phase nanostructured bulk Yb0.2Co4Sb12 skutterudites have been prepared by combining a melt spinning technique with spark plasma sintering. The effects of a pre-annealing
process on the microstructure and phase composition of ribbon samples and bulk materials are investigated. After the pre-annealing
process, average grain size increases from 200 nm to 300 nm for ribbon samples and from 250 nm to 350 nm for bulk materials,
and nearly single-phase skutterudites have formed. Because of the nanostructure, the thermal conductivity of bulk skutterudites
notably decreases 25% at 800 K. As␣a result, the ZT values are improved compared with starting material prepared by the traditional method. 相似文献
16.
采用真空热蒸发以及退火工艺制备了支持局域表面等离激元的微纳结构薄膜,在此薄膜上蒸镀了硫系玻璃Ge28Sb12Se60薄膜。应用Z-扫描技术,在飞秒激光脉冲激发下研究其光学非线性增强的色散特性,在650 nm和850 nm波段观察到了非线性吸收增强;非线性折射率随着波长的增加由负变正。通过扫描电子显微镜和透过光谱表征和分析了硫系玻璃Ge28Sb12Se60薄膜非线性吸收增强的原理,非线性吸收随着波长的增加由单光子吸收为主逐渐转变为双光子吸收为主;银膜的微纳结构导致硫系玻璃薄膜的共振中心频率发生了偏移。实验制备的用于增强硫系玻璃非线性的微纳结构制作简单,无需复杂光刻工艺,为非线性光子学器件的设计提供了新的思路。 相似文献
17.
In this study, we investigated the impact of the Ce filling fraction on the thermoelectric properties of p-type filled skutterudites Ce y Fe3CoSb12 (y = 0.6 to 1.0). The electrical conductivity decreases gradually with increasing y, while the Seebeck coefficient displays an opposite variation tendency, consistent with the expected electron donor role of the Ce filler in this compound. The overall power factors are invariable among all the samples. Alteration of the Ce filling fraction exerts little influence on the phonon transport, but the total thermal conductivity markedly declined with increasing y due to the reduced contribution to heat transfer from carriers. As a consequence, the maximum thermoelectric figure of merit ZT reaches ~0.8 for the sample with y = 0.9, comparable to that of pure Fe-based skutterudite CeFe4Sb12; more importantly, the former possesses a much larger average ZT between 300 K and 800 K than the latter, showing superior potential for use in intermediate-temperature thermoelectric power generation applications. Further enhancement of ZT in p-type Fe3CoSb12-based skutterudites could be realized via nanostructuring or a multiple-filling approach. 相似文献
18.
19.
Reactive-ion etching of Ge2Sb2Te5 in CF4/Ar plasma for non-volatile phase-change memories 总被引:1,自引:0,他引:1
Etching of Ge2Sb2Te5 (GST) is a critical step in the fabrication of chalcogenide random access memories. In this paper, the etch characteristics of GST films were studied with a CF4/Ar gas mixture using a reactive-ion etching system. We observed a monotonic decrease in etch rate with decreasing CF4 concentration indicating its importance in defining the material removal rate. Argon, on the other hand, plays an important role in defining the smoothness of the etched surface and sidewall edge acuity. We have studied the importance of gas mixture and RF power on the quality of the etched film. The smoothest surfaces and most vertical sidewalls were achieved using a CF4/Ar gas mixture ratio of 10/40, a background pressure of 80 mTorr, and power of 200 W. 相似文献
20.
文中利用热蒸发以及退火等工艺制备了支持局域表面等离子体激元(LSP)的微纳结构,来增强硫系玻璃Ge28Sb12Se60 (GSS)薄膜的非线性吸收效应;搭建了Z-scan光路,实现了对样品非线性折射与吸收的测量;通过对样品透射光谱的分析,揭示了GSS非线性吸收增强效应的原理。并研究了该微纳结构对不同厚度GSS非线性吸收的增强规律。文中用到的LSP微纳结构制作简单,无需复杂光刻工艺,可为增强材料光学非线性研究提供重要参考。 相似文献