共查询到20条相似文献,搜索用时 31 毫秒
1.
C. Navone M. Soulier M. Plissonnier A. L. Seiler 《Journal of Electronic Materials》2010,39(9):1755-1759
In major applications, optimal power will be achieved when thermoelectric films are at least 100 μm thick. In this paper we demonstrate that screen-printing is an ideal method to deposit around 100 μm of (Bi,Sb)2(Te,Se)3-based films on a rigid or flexible substrate with high Seebeck coefficient value (90 μV K−1 to 160 μV K−1) using a low-temperature process. Conductive films have been obtained after laser annealing and led to acceptable thermoelectric
performance with a power factor of 0.06 μW K−2 cm−1. While these initial material properties are not at the level of bulk materials, the complete manufacturing process is cost-effective,
compatible with large surfaces, and affords a mass-production technique. 相似文献
2.
Silver doped p-type Mg2Ge thin films were grown in situ at 773 K using magnetron co-sputtering from individual high-purity Mg and Ge targets. A sacrificial
base layer of silver of various thicknesses from 4 nm to 20 nm was initially deposited onto the substrate to supply Ag atoms,
which entered the growing Mg2Ge films by thermal diffusion. The addition of silver during film growth led to increased grain size and surface microroughness.
The carrier concentration increased from 1.9 × 1018 cm−3 for undoped films to 8.8 × 1018 cm−3 for the most heavily doped films, but it did not reach saturation. Measurements in the temperature range of T = 200–650 K showed a positive Seebeck coefficient for all the films, with maximum values at temperatures between 400 K and
500 K. The highest Seebeck coefficient of the undoped film was 400 μV K−1, while it was 280 μV K−1 for the most heavily doped film at ∼400 K. The electrical conductivity increased with silver doping by a factor of approximately
10. The temperature effects on power factors for the undoped and lightly doped films were very limited, while the effects
for the heavily doped films were substantial. The power factor of the heavily doped films reached a non-optimum value of ∼10−5 W cm−1 K−2 at 700 K. 相似文献
3.
Yong Liu Yuan-Hua Lin Jinle Lan Bo-Ping Zhang Wei Xu Ce-Wen Nan Hongmin Zhu 《Journal of Electronic Materials》2011,40(5):1083-1086
Polycrystalline In2O3 ceramics co-doped with Zn and Nd were prepared by the spark plasma sintering (SPS) process, and microstructure and thermoelectric
(TE) transport properties of the ceramics were investigated. Our results indicate that co-doping with Zn2+ and Nd3+ shows a remarkable effect on the transport properties of In2O3-based ceramics. Large electrical conductivity (~130 S cm−1) and thermopower (~220 μV K−1) can be observed in these In2O3-based ceramic samples. The maximum power factor (PF) reaches 5.3 × 10−4 W m−1 K−2 at 973 K in the In1.92Nd0.04Zn0.04O3 sample, with a highest ZT of ~0.25. 相似文献
4.
H. Udono K. Nakamori Y. Takahashi Y. Ujiie I. J. Ohsugi T. Iida 《Journal of Electronic Materials》2011,40(5):1165-1170
We have investigated the crystal growth of single-phase MnSi1.75−x
by a temperature gradient solution growth (TGSG) method using Ga and Sn as solvents and MnSi1.7 alloy as the solute, and measured the thermoelectric properties of the resulting crystals. Single-phase Mn11Si19 and Mn4Si7 crystals were grown successfully using Ga and Sn as solvents, respectively. The typical size of a grown ingot of Mn11Si19 was 2 mm to 4 mm in thickness and 12 mm in diameter, whereas Mn4Si7 had polyhedral shape with dimensions in the range of several millimeters. The single-phase Mn11Si19 has good electrical conduction (ρ = 0.89 × 10−3 Ω cm to 1.09 × 10−3 Ω cm) compared with melt-grown multiphase higher-manganese silicide (HMS) crystals. The Seebeck coefficient, power factor,
and thermal conductivity were 77 μV K−1 to 85 μV K−1, 6.7 μW cm−1 K−2 to 7.2 μW cm−1 K−2, and 0.032 W cm−1 K−1, respectively, at 300 K. 相似文献
5.
Wei Liu Qiang Zhang Xinfeng Tang Han Li Jeff Sharp 《Journal of Electronic Materials》2011,40(5):1062-1066
Mg2(Si0.3Sn0.7)1−y
Sb
y
(0 ≤ y ≤ 0.04) solid solutions were prepared by a two-step solid-state reaction method combined with the spark plasma sintering
technique. Investigations indicate that the Sb doping amount has a significant impact on the thermoelectric properties of
Mg2(Si0.3Sn0.7)1−y
Sb
y
compounds. As the Sb fraction y increases, the electron concentration and electrical conductivity of Mg2(Si0.3Sn0.7)1−y
Sb
y
first increase and then decrease, and both reach their highest value at y = 0.025. The sample with y = 0.025, possessing the highest electrical conductivity and one of the higher Seebeck coefficient values among all the samples,
has the highest power factor, being 3.45 mW m−1 K−2 to 3.69 mW m−1 K−2 in the temperature range of 300 K to 660 K. Meanwhile, Sb doping can significantly reduce the lattice thermal conductivity
(κ
ph) of Mg2(Si0.3Sn0.7)1−y
Sb
y
due to increased point defect scattering, and κ
ph for Sb-doped samples is 10% to 20% lower than that of the nondoped sample for 300 K < T < 400 K. Mg2(Si0.3Sn0.7)0.975Sb0.025 possesses the highest power factor and one of the lower κ
ph values among all the samples, and reaches the highest ZT value: 1.0 at 640 K. 相似文献
6.
Colby L. Heideman Raimar Rostek Michael D. Anderson Andrew A. Herzing Ian M. Anderson David C. Johnson 《Journal of Electronic Materials》2010,39(9):1476-1481
An ultralow-thermal-conductivity compound with the ideal formula [(PbSe)1.00]1[MoSe2]1 has been successfully crystallized across a range of compositions. The lattice parameters varied from 1.246 nm to 1.275 nm,
and the quality of the observed 00ℓ diffraction patterns varied through the composition region where the structure crystallized. Measured resistivity values
ranged over an order of magnitude, from 0.03 Ω m to 0.65 Ω m, and Seebeck coefficients ranged from −181 μV K−1 to 91 μV K−1 in the samples after the initial annealing to form the basic structure. Annealing of samples under a controlled atmosphere
of selenium resulted in low conductivities and large negative Seebeck coefficients, suggesting an n-doped semiconductor. Scanning transmission electron microscopy cross-sections confirmed the interleaving of bilayers of PbSe
with Se-Mo-Se trilayers. High-angle annular dark-field images revealed an interesting volume defect, where PbSe grew through
a region where a layer of MoSe2 would be expected in the perfect structure. Further studies are required to correlate the density of these defects with the
observed electrical properties. 相似文献
7.
L. P. Kazakova K. D. Tsendin E. A. Lebedev D. Arsova I. A. Obukhova 《Semiconductors》2010,44(1):76-78
Charge-carrier transport in Ge20As20S60 films has been studied using the transit time method under low-injection conditions at room temperature. It was found that
drift mobilities of electrons and holes in Ge20As20S60 films are close to each other, i.e., μ
e
≈ μ
h
≈ 2 × 10−3 cm2 V−1 s−1 at T = 295 K and F = 5 × 104 V/cm. It was shown that the time dependence of the photocurrent during carrier drift and the voltage dependence of the drift
mobility allowed the use of the concept of anomalous dispersive transport. Experimental data were explained using the model
of transport controlled by carrier trapping by localized states with energy distribution near conduction and valence band
edges described by the exponential law with a characteristic energy of ∼0.05 eV. 相似文献
8.
V. Ponnambalam Bo Zhang Terry M. Tritt S. Joseph Poon 《Journal of Electronic Materials》2007,36(7):732-735
The usefulness of half-Heusler (HH) alloys as thermoelectrics has been mainly limited by their relatively large thermal conductivity,
which is a key issue despite their high thermoelectric power factors. In this regard, Bi-containing half-Heusler alloys are
particularly appealing, because they are, potentially, of low thermal conductivity. One such a material is ZrCoBi. We prepared
pure and Ni-doped ZrCoBi by a solid-state reaction. To evaluate thermoelectric potential we measured electrical resistivity
(ρ = 1/σ) and thermopower (σ) up to 1000 K and thermal conductivity (κ) up to 300 K. Our measurements indicate that for these alloys resistivity of approximately a few mΩ cm and thermopower larger
than a hundred μV K−1 are possible. Low κ values are also possible. On the basis of these data we conclude that this system has a potential to be optimized further,
despite the low power factors (α
2
σT) we have currently measured. 相似文献
9.
In this paper, a novel and simple sodium alginate (SA) gel method was developed to prepare γ-Na
x
Co2O4. This method involved the chemical gelling of SA in the presence of Co2+ ions by cross-linking. After calcining at 700°C to 800°C, single-phase γ-Na
x
Co2O4 crystals were obtained. The arrangement of about 1 μm to 4 μm flaky particles exhibited a well-tiled structure along the plane direction of the flaky particles. SA not only acted as
the control agent for crystal growth, but also provided a Na source for the γ-Na
x
Co2O4 crystals. The electrical properties of γ-Na
x
Co2O4 ceramics prepared via ordinary sintering after cold isostatic pressing were investigated. The Seebeck coefficient and power
factor of the bulk material were 177 μV K−1 and 4.3 × 10−4 W m−1 K−2 at 850 K, respectively. 相似文献
10.
Thermoelectric materials are attractive since they can recover waste heat directly in the form of electricity. In this study,
the thermoelectric properties of ternary rare-earth sulfides LaGd1+x
S3 (x = 0.00 to 0.03) and SmGd1+x
S3 (x = 0.00 to 0.06) were investigated over the temperature range of 300 K to 953 K. These sulfides were prepared by CS2 sulfurization, and samples were consolidated by pressure-assisted sintering to obtain dense compacts. The sintered compacts
of LaGd1+x
S3 were n-type metal-like conductors with a thermal conductivity of less than 1.7 W K−1 m−1. Their thermoelectric figure of merit ZT was improved by tuning the chemical composition (self-doping). The optimized ZT value of 0.4 was obtained in LaGd1.02S3 at 953 K. The sintered compacts of SmGd1+x
S3 were n-type hopping conductors with a thermal conductivity of less than 0.8 W K−1 m−1. Their ZT value increased significantly with temperature. In SmGd1+x
S3, the ZT value of 0.3 was attained at 953 K. 相似文献
11.
Thin films of the semiconducting compound Mg2Ge were deposited by magnetron cosputtering from source targets of high-purity Mg and Ge onto glass substrates at temperatures
T
s = 300°C to 700°C. X-ray diffraction shows that the Mg2Ge compound begins to form at a substrate temperature T
s ≈ 300°C. Films deposited at T
s = 400°C to 600°C are single-phase Mg2Ge and have strong x-ray peaks. At higher T
s the films tend to be dominated by a Ge-rich phase primarily due to the loss of magnesium vapor from the condensing film.␣At
optimum deposition temperatures, 550°C to 600°C, films have an electrical conductivity σ
600 K = 20 Ω−1 cm−1 to 40 Ω−1 cm−1 and a Seebeck coefficient α = 300 μV K−1 to 450 μV K−1 over a broad temperature range of 200 K to 600 K. 相似文献
12.
Zhen-Hua Ge Bo-Ping Zhang Peng-Peng Shang Yi-Qiang Yu Chen Chen Jing-Feng Li 《Journal of Electronic Materials》2011,40(5):1087-1094
Bismuth sulfide (Bi2S3) polycrystalline samples were fabricated by mechanical alloying (MA) combined with spark plasma sintering (SPS). The microstructure
and electrical transport properties were investigated with special emphasis on the influence of the ball-milling process.
Bi2S3 compound powders could be readily synthesized directly from elemental powders under all the investigated conditions, and
highly dense n-type bulk Bi2S3 samples with high density (>95%) were fabricated by the subsequent SPS process. Changing the MA conditions had no apparent
influence on the microstructure or phase structure of the MA-derived Bi2S3 powders, but the electrical properties and thermopower of the SPS-sintered Bi2S3 bulk samples were greatly dependent on the MA speed and time. The power factor of Bi2S3 was increased to 233 μW K−2 m−1 at 573 K by optimizing the ball-milling process. This power factor is higher than values reported to date for Bi-S binary
samples without texture. 相似文献
13.
A. P. Gonçalves G. Delaizir E. B. Lopes L. M. Ferreira O. Rouleau C. Godart 《Journal of Electronic Materials》2011,40(5):1015-1017
Despite the fact that glasses have interesting characteristics for thermoelectric (TE) applications, their potential as TE
materials has only recently been tested. In a recent article, we focused on glasses based on the Ge20Te80 composition, which has a high Seebeck coefficient, S, showing that in Cu
x+y
Ge20−x
Te80−y
the power factor, S
2/ρ (where ρ is the resistivity), strongly improves with increasing Cu concentration. Herein we report on the preparation of glasses in
the Cu-Te-As system and their characterization by x-ray diffraction (XRD), differential scanning calorimetry (DSC), and measurements
of ρ and S. Our preliminary results show that the melt-spinning technique allows us to extend the Cu-Te-As glassy domain and leads to
T
g values that permit use of these glasses in applications up to 100°C. A maximum S
2/ρ value of ∼100 μW K−2 m−1 was obtained for the Cu30As15Te55 composition, confirming the potential of these glasses for TE applications. 相似文献
14.
Mg2Sn compounds were prepared by the modified vertical Bridgman method, and were doped with Bi and Ag to obtain n- and p-type materials, respectively. Excess Mg was also added to some of the ingots to compensate for the loss of Mg during the
preparation process. The Mg2Sn samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM), and their power factors were
calculated from the Seebeck coefficient and electrical conductivity, measured from 80 K to 700 K. The sample prepared with
4% excess Mg, which contains a small amount of Mg2Sn + Mg eutectic phase, had the highest power factor of 12 × 10−3 W m−1 K−2 at 115 K, while the sample doped with 2% Ag, in which a small amount of eutectics also exists, has a power factor of 4 × 10−3 W m−1 K−2 at 420 K. 相似文献
15.
Ternary rare-earth sulfides NdGd1+x
S3, where 0 ≤ x ≤ 0.08, were prepared by sulfurizing Ln2O3 (Ln = Nd, Gd) with CS2 gas, followed by reaction sintering. The sintered samples have full density and homogeneous compositions. The Seebeck coefficient,
electrical resistivity, and thermal conductivity were measured over the temperature range of 300 K to 950 K. All the sintered
samples exhibit a negative Seebeck coefficient. The magnitude of the Seebeck coefficient and the electrical resistivity decrease
systematically with increasing Gd content. The thermal conductivity of all the sintered samples is less than 1.9 W K−1 m−1. The highest figure of merit ZT of 0.51 was found in NdGd1.02S3 at 950 K. 相似文献
16.
We performed thermoelectric characterizations on TlCu3Te2: (Tl1+)(Cu1+)3 (Te2−)2 and TlCu2Te2: (Tl1+)(Tl3+)(Cu1+)4(Te2−)4, in order to understand the relationship between the thermoelectric properties (especially the lattice thermal conductivity
κ
lat) and the valence states of Tl. The thermal conductivity of TlCu2Te2 is high (about 8 W m−1 K−1), while that of TlCu3Te2 is extremely low (around 0.5 W m−1 K−1) like other thallium tellurides. This high κ of TlCu2Te2 was caused not only by its large electronic contribution but also by its intrinsically high κ
lat. The present study implies that the valence states of Tl would play some important roles in determining the magnitude of
κ
lat. 相似文献
17.
Horst Brodowsky Matthias Albus Qiyuan Chen Zhongliang Xiao Zhoulan Yin 《Journal of Electronic Materials》2011,40(5):907-914
The thermoelectric power of Rh and Ir was redetermined between 100 K and 1400 K. It varies almost linearly from +1.7 μV K−1 to −3.8 μV K−1 for Rh and from +1.5 μV K−1 to −2.2 μV K−1 for Ir. The diffusive part of the thermopower could be calculated from the density of states. It is approximately equal to
the temperature dependence of the electrochemical potential of the electrons divided by the electronic charge. This is attributed
to the approximate establishment of local equilibrium between electrons and lattice atoms above 400 K—a condition not fulfilled
in the phonon-drag regime below 300 K. 相似文献
18.
B. N. Pantha R. Dahal J. Li J. Y. Lin H. X. Jiang G. Pomrenke 《Journal of Electronic Materials》2009,38(7):1132-1135
We report on the experimental investigation of the potential of InGaN alloys as thermoelectric (TE) materials. We have grown
undoped and Si-doped In0.3Ga0.7N alloys by metalorganic chemical vapor deposition and measured the Seebeck coefficient and electrical conductivity of the
grown films with the aim of maximizing the power factor (P). It was found that P decreases as electron concentration (n) increases. The maximum value for P was found to be 7.3 × 10−4 W/m K2 at 750 K in an undoped sample with corresponding values of Seebeck coefficient and electrical conductivity of 280 μV/K and 93␣(Ω cm)−1, respectively. Further enhancement in P is expected by improving the InGaN material quality and conductivity control by reducing background electron concentration. 相似文献
19.
Hong Fu Pengzhan Ying Jiaolin Cui Yanming Yan Xiaojun Zhang 《Journal of Electronic Materials》2011,40(5):937-941
In-Sn-Te-based alloys usually have low electrical and thermal conductivity. In the present work we substituted Al for In in
an In-Sn-Te alloy and prepared an (In1.9Al0.1Te3)0.08(SnTe)0.92 alloy by spark plasma sintering. Substitution of Al for In favors the formation of indium impurity levels in this structure
and accounts for the decrease of the band gap (E
g) and much of the increase of mobility and electrical conductivity. The thermal conductivity decreases from 1.72 W K−1 m−1 to 1.44 W K−1 m−1 with temperature, while that of the (In2Te3)0.08(SnTe)0.92 alloy increases from 2.29 W K−1 m−1 to 3.50 W K−1 m−1. The thermoelectric figure of merit (ZT) of the sample increases with measurement temperature, and the highest ZT value of 0.28 was obtained at 668 K, being a factor of 4.5 greater than the maximum ZT value for the Al-free (In2Te3)0.08(SnTe)0.92 alloy at 510 K. 相似文献
20.
We report here the results of magnetotransport and electrical resistivity (ρ) measurements in the temperature range of 4.2–320
K and in the presence of magnetic fields up to 10 T on the Ru-doped, bilayered manganite system, La1.2Ca1.8Mn2−xRuxO7 (0≤x≤1). We find that the Ru doping affects the magnetotransport properties considerably. The ρ versus H data were analyzed
by fitting the data to the power-law equation, ρ = ρ0 − αHn. The isothermal magnetoresistance (MR) versus H curves taken up to ± 10 T are highly symmetrical, and their curvature changes
from concave up to concave down as the temperature increases. The MR, defined as [ρ(H) − ρ(0)]/ρ(0), is found to increase
with Ru doping from 58% to 64% up to x=0.1 and to decrease to 45% for the x=1 sample at 10 K. Analysis of the ρ-T data below
30 K shows that, at low temperature, the system behaves like a disordered metal. 相似文献