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1.
S. H. Yang T. J. Zhu C. Yu J. J. Shen Z. Z. Yin X. B. Zhao 《Journal of Electronic Materials》2011,40(5):1244-1248
(GeTe)90(Ag
y
Sb2−y
Te3−y
)10 (y = 0.6, 0.7, 0.8, 1.0) compounds were prepared by combining melting and hot pressing, and the thermoelectric properties were
studied over the temperature range of 300 K to 770 K. Powder x-ray diffraction results revealed that all the samples were
the rhombohedral phase with space group R3m. The electrical conductivity of samples decreased with temperature, while the Seebeck coefficient increased. The thermal
conductivity of all the samples was very low, especially for those with the lower y values. High ZT values above 1.6 were obtained for the samples with y = 0.6, 0.7, and 0.8. 相似文献
2.
T. Ohnishi M. Naito S. Mizusaki Y. Nagata Y. Noro 《Journal of Electronic Materials》2011,40(5):915-919
The magnetic, transport, and thermoelectric properties of Ca1−x
Sr
x
Ru1−y
Mn
y
O3 have been investigated. Ferromagnetism with relatively high T
C (>200 K) was introduced by Mn doping. In particular, ferromagnetism appeared in the Ca0.5Sr0.5Ru1−y
Mn
y
O3 system at y > 0.2. The maximum T
C (=270 K) was recorded for a specimen of Ca0.5Sr0.5Ru0.4Mn0.6O3. The ferromagnetism seems to be due to the mixed-valence states of Mn3+, Mn4+, Ru4+, and Ru5+ ions. The metallic character of Ru-rich specimens was suppressed by Mn substitution, and the system was transformed into
a semiconductor at relatively low Mn content near y = 0.1. Specimens with higher Mn content (y > 0.8) had large thermoelectric power (50 μV K−1 to 130 μV K−1 at 280 K) accompanied by relatively low resistivity (0.03 Ω cm to 1 Ω cm). The Ca0.5Sr0.5Ru1−y
Mn
y
O3 system seems to have good potential as a thermoelectric material for use above 300 K. 相似文献
3.
J. Leszczynski A. Dauscher P. Masschelein B. Lenoir 《Journal of Electronic Materials》2010,39(9):1764-1768
Interesting results for cobalt triantimonide partially filled with indium have encouraged us to explore skutterudites filled
with higher indium fractions. For pure In
x
Co4Sb12, the fraction of voids filled is limited to about x = 0.25. To enable the insertion of more indium atoms, charge compensation is necessary. In this work, we studied the skutterudite
compound In
x
Fe
y
Co4−y
Sb12 partially filled with indium, where iron substitution for cobalt was employed for charge compensation. Polycrystalline samples
were prepared by direct reaction of constituents. Structural and chemical characterization were accomplished by x-ray diffraction
and energy-dispersive x-ray spectroscopy. Electrical resistivity, thermoelectric power, and thermal conductivity were measured
between 2 K and 350 K. The influence of indium and iron on the charge-carrier transport properties and thermal conductivity
in In
x
Fe
y
Co4−y
Sb12 compounds is presented and discussed. 相似文献
4.
Xin Zhang Xu-yi Ma Qing-mei Lu Fei-peng Zhang Yan-qin Liu Jiu-xing Zhang Lei Wang 《Journal of Electronic Materials》2011,40(5):773-777
n-Type thermoelectric powders of (Bi2−x
Ag
x
Te3)0.96−(Bi2Se3)0.04 (0 ≤ x ≤ 0.05) have been synthesized by mechanical alloying and then consolidated by spark plasma sintering. The analysis results
show that the grain size of pure Bi, Te, Ag, and Se powders is decreased to about 1 μm to 0.5 μm after they are mechanically alloyed for 2 h. The power factor of bulk material increases with increasing Ag-doping content,
while the trend for the lattice thermal conductivity is the opposite. Bulk (Bi0.99Ag0.04)2(Te0.96Se0.04)3 after milling for 12 h exhibits a higher power factor, lower thermal conductivity, and thus a higher ZT of 0.74 at 373 K. 相似文献
5.
The experimental results of synthesizing thin films (<1 μm thick) of (SnO2)
x
(In2O3)1 − x
(x = 0.5–1 wt) nanocomposites fabricated by high-frequency magnetron sputtering of metal-oxide targets in a controlled Ar +
O2 atmosphere are presented. The films, deposited on hot substrates (400°C), are studied by the X-ray diffraction analysis,
atomic-force microscopy, and optical and electrical methods. The effect of the synthesis conditions and film composition on
the size of crystalline grains, band gap, and the concentration and mobility of free charge carriers was determined. It is
shown that films of the composition (SnO2)
x
(In2O3)1 − x
with x = 0.9 are the most promising for applications in gas sensorics. 相似文献
6.
G. A. Bordovsky A. V. Marchenko E. I. Terukov P. P. Seregin T. V. Likhodeeva 《Semiconductors》2008,42(11):1323-1326
Tin is stabilized in the bivalent and tetravalent states in the structure of (As2Se3)1 − z
(SnSe2)
z − x
(Tl2Se)
x
and (As2Se3)1 − z
(SnSe)
z − x
(Tl2Se)
x
glasses. The presence of bivalent tin in the structural network of a glass does not give rise to extrinsic conductivity.
Dependences of density, microhardness, and the glass-transition temperature on the composition of the glasses are interpreted
using a model according to which the structure of the glasses is composed of structural units that correspond to As2Se3, AsSe, TlAsSe2, Tl2Se, SnSe, and SnSe2 compounds.
Original Russian Text ? G.A. Bordovsky, A.V. Marchenko, E I. Terukov, P.P. Seregin, T.V. Likhodeeva, 2008, published in Fizika
i Tekhnika Poluprovodnikov, 2008, Vol. 42, No. 11, pp. 1353–1356. 相似文献
7.
Lingxia Li Yucui Wang Wangsuo Xia Xiaowei He Ping Zhang 《Journal of Electronic Materials》2012,41(4):684-688
Ceramics of nominal composition (Zn1−x Mg x )2SiO4 were synthesized by the solid-state method. The phase evolution, microstructure, and microwave dielectric characteristics of the (Zn1−x Mg x )2SiO4 (0 < x < 1.0) ceramics were investigated systematically. The sintering range was widened and the densification temperatures of the present ceramics were much lower compared with the Zn2SiO4 and Mg2SiO4 end-members. Coexistence of Mg2SiO4 and Zn2SiO4 phases was observed in the (Zn1−x Mg x )2SiO4 ceramics with x = 0.4 and 0.6. The MgSiO3 secondary phase was also observed due to Mg substitution. Changes in grain shapes from equiaxed to rectangular were observed in sintered samples as x varied from 0.7 to 1.0. The microwave characteristics of (Zn1−x Mg x )2SiO4 ceramics were significantly improved by the suppression of the MgSiO3 phase, where an enhanced quality factor (Qf) value was obtained. The best microwave characteristics were achieved in the (Zn1−x Mg x )2SiO4 ceramic with Zn/Mg ratio of 1.5 sintered at 1250°C: ε r = 6.2, Qf = 148,740 GHz, τ f = −54.2 ppm/°C. 相似文献
8.
The optical properties of quaternary GaN
x
As
y
P1 − x − y
semiconductor alloys grown on a GaP (100) substrate surface are studied by photoluminescence spectroscopy in the temperature
range 20–300 K and by photoluminescence excitation spectroscopy at liquid-nitrogen temperature. The measurements are carried
out for the GaN
x
As
y
P1 − x − y
alloys, for which the nitrogen and arsenic molar fractions x and y range from 0.006 to 0.012 and from 0.00 to 0.18, respectively. A comparative analysis of the data is conducted, and the dependences
of the energy position of the photoluminescence peak on the composition of the quaternary alloy are established. From the
studies of photoluminescence in the range 20–300 K, it is found that the temperature dependence of the position of the photoluminescence
peak substantially differs from the behavior described by Varshni’s expression. 相似文献
9.
E. N. Vigdorovich 《Semiconductors》2011,45(13):1642-1645
Some properties of the In1 − y
Ga
y
As1 − x
N
x
unordered alloys and physical prerequisites of their use in science and technology are considered. The results of studying
the intermolecular interaction in the systems under study and the features of their application to the In1 − y
Ga
y
As1 − x
N
x
/GaAs functional hetero-structures are presented. 相似文献
10.
P. V. Seredin A. V. Glotov V. E. Ternovaya E. P. Domashevskaya I. N. Arsentyev L. S. Vavilova I. S. Tarasov 《Semiconductors》2011,45(11):1433-1440
Using X-ray structural analysis, scanning electron microscopy, atomic force microscopy, and photoluminescent spectroscopy,
it is shown that it is possible to obtain a small-scale domain structure on the surface of liquid-phase epitaxial heterostructures.
The domain structure emerges as a result of spinodal decomposition of the Ga
x
In1 − x
As
y
P1 − y
quaternary alloy due to immiscibility of its components and relaxation of its lattice parameter to surrounding layers. 相似文献
11.
Y. Liang H. Borrmann W. Schnelle J. Goraus J. T. Zhao Yu. Grin 《Journal of Electronic Materials》2010,39(9):1837-1841
A new compound with the filled-skutterudite structure, Ba
x
Pd4Sn
y
Sb12−y
, was prepared by the flux growth and spark plasma sintering (SPS) techniques. The crystal structure was determined from single
crystal and powder x-ray diffraction data. The structure is electronically stabilized by the Sn:Sb ratio, and the lattice
parameters depend on this ratio. For magnetic, electrical conductivity, Hall coefficient, Seebeck coefficient and thermal
conductivity measurements, single crystal and/or SPS-densified specimens were utilized. Ba1.0Pd4Sn7.1Sb5.2 exhibits diamagnetic behavior. The Hall coefficient is negative and increases with temperature. The lattice thermal conductivity
of Ba0.97Pd4Sn6.90Sb4.97 (SPS-densified) is smaller than for CoSb3, but the thermoelectric figure of merit (ZT) is comparatively low due to the low Seebeck coefficient. 相似文献
12.
The results of calculations of the band gap in GaP
x
N
y
As1 − x − y
alloys and the estimated parameter of hybridization of the conduction band in GaP and the localized level of nitrogen are
reported. The optical properties of quantum-confined heterostructures based on GaP
x
N
y
As1 − x − y
alloys synthesized on the GaP (100) substrate surface are studied by photoluminescence measurements in the temperature range
of 15–300 K. The heterostructures consist of GaP0.814N0.006As0.18 quantum wells separated by GaP barrier layers. The well width and the barrier thickness are 5 nm. Heterostructures with different
numbers of periods are considered. On optical excitation of the structures, an intense photoluminescence line is observed
in the spectral range 620–650 nm. The photoluminescence spectra of the GaP0.814N0.006As0.18/GaP quantum wells are profoundly broadened because of the inhomogeneity of the quaternary alloy in composition. It is established
that the increase in the number of quantum well layers from 10 to 25 does not results in degradation of the photoluminescence
properties of the heterostructures. The results of the study support the view that it is possible to produce efficient optoelectronic
devices on the basis of GaP
x
N
y
As1 − x − y
alloys. 相似文献
13.
Virginie Richoux Sebastien Diliberto Clotilde Boulanger 《Journal of Electronic Materials》2010,39(9):1914-1919
Bismuth antimony telluride (Bi1−x
Sb
x
)2Te3 thermoelectric compounds were synthesized by pulse plating. Due to the large number of parameters available (pulse waveform,
on/off pulse time, applied current density), this advanced form of electrodeposition allows better control of the interfacial
supply and electrochemical reactions and offers effective ways to improve macroscopic properties such as adhesion and to produce
crack-free hard deposits and fine-grained films with higher uniformity and lower porosity. The influence of pulse parameters
(pulse time t
on, cathodic current density J
c) on the stoichiometry, roughness, and crystallography of deposits was studied. The thermoelectric properties (electrical
resistivity and Seebeck coefficient) of the films were measured. The results revealed that deposits have p-type conductivity directly after electroplating (Seebeck coefficient around 150 μV K−1), in contrast to films synthesized by direct current, which require annealing. An improvement of resistivity was observed:
for a direct-current-deposited film the resistivity is around 5000 μΩ m, whereas for a pulse-deposited film the resistivity was around 200 μΩ m. 相似文献
14.
Using directional crystallization of the melt of the (FeIn2S4)
x
(MnIn2S4)1 − x
alloy, homogeneous crystals of a similar atomic composition are grown over the entire range of compositions 1 ≥ x ≥ 0. It is established that the crystals of the continuous series of quaternary alloys in the range x = 0–1 crystallize in the spinel structure and lattice parameter a linearly depends on x. It is established that it is possible to obtain In(Al)/(FeIn2S4)
x
(MnIn2S4)1–x
photosensitive structures. Room-temperature spectra of relative quantum efficiency of photoconversion of the In(Al)/(FeIn2S4)
x
(MnIn2S4)1 − x
structures fabricated for the first time are obtained. From the analysis of these spectra, activation energies of direct
and indirect band-to-band transitions for the crystals of the (FeIn2S4)
x
(MnIn2S4)1–x
alloys are determined and the dependence of these parameters on the composition of the position-disordered phases of mentioned
alloys is discussed. It is concluded that the crystals of the (FeIn2S4)
x
(MnIn2S4)1 − x
alloys can be used in broadband photoconverters of optical radiation. 相似文献
15.
F. Kawashima X.Y. Huang K. Hayashi Y. Miyazaki T. Kajitani 《Journal of Electronic Materials》2009,38(7):1159-1162
We have investigated the effects of Bi doping on the crystal structure and high-temperature thermoelectric properties of the
n-type layered oxide Ca2MnO4−γ
. The electrical conductivity σ and the absolute value of the Seebeck coefficient S were, respectively, found to increase and decrease with Bi doping. The thermal conductivity κ of doped Ca2MnO4−γ
is relatively low, 0.5 W/m K to 1.8 W/m K (27°C to 827°C). Consequently, the ZT value, ZT = σS
2
T/κ, increases with Bi doping. The maximum ZT is 0.023 for Ca1.6Bi0.18MnO4−γ
at 877°C, which is ten times higher than that of the end member, Ca2MnO4−γ
. The increase of ZT mainly results from the considerable increase of σ, which can be explained in terms of structural change. The␣Mn-O(1) and the Mn-O(2) distances in the c-direction and ab-plane, respectively, increase with increasing Bi concentration, indicating that the valence state of Mn ions decreases with
the increase of electron carriers in the CaMnO3 layers. In addition, the Mn-O(2)-Mn bond angle increases linearly with Bi doping, leading to an improvement of the electron
carrier mobility. 相似文献
16.
Bi
x
Sb2−x
Te3 bulk alloys are known as the best p-type thermoelectric materials near room temperature. In this work, single-phase Bi
x
Sb2−x
Te3 (x = 0.2, 0.25, 0.3, 0.34, 0.38, 0.42, 0.46, and 0.5) alloys were prepared by spark plasma sintering (SPS) using mechanical
alloying (MA)-derived powders. A small amount (0.1 vol.%) of SiC nanoparticles was added to improve the mechanical properties
and to reduce the thermal conductivity of the alloys. The electrical resistivity decreases significantly with increasing ratio
of Sb to Bi in spite of the weaker decreasing trend in Seebeck coefficient, whereby the power factor at 323 K reaches 3.14 × 10−3 W/mK2 for a sample with x = 0.3, obviously higher than that at x = 0.5 (2.27 × 10−3 W/mK2), a composition commonly used for ingots. Higher thermal conductivities at low temperatures are obtained at the compositions
with lower x values, but they tend to decrease with temperature. As a result, higher ZT values are obtained for Bi0.3Sb1.7Te3, with a maximum ZT value of 1.23 at 423 K, about twice the ZT value (about 0.6) of Bi0.5Sb1.5Te3 at the same temperature. 相似文献
17.
Pure Bi2Te3 and Bi2Se3 nanopowders were hydrothermally synthesized, and n-type Bi2Te3−x
Se
x
bulk samples were prepared by hot pressing a mixture of Bi2Te3 and Bi2Se3 nanopowders at 623 K, 648 K or 673 K and 80 MPa in vacuum. The phase composition of the powders and bulk samples were characterized
by x-ray diffraction. The morphology of the powders was examined by transmission electron microscopy. The microstructure and
composition of the bulk samples were characterized by field-emission scanning electron microscopy and energy-dispersive x-ray
spectroscopy, respectively. The density of the samples increased with sintering temperature. The samples were somewhat oxidized,
and the amount of oxide (Bi2TeO5) present increased with sintering temperature. The samples consisted of sheet-like grains with a thickness less than 100 nm.
Seebeck coefficient, electrical conductivity, and thermal conductivity of the samples were measured from room temperature
up to 573 K. Throughout the temperature range investigated, the sample sintered at 623 K had a higher power factor than the
samples sintered at 648 K or 673 K. 相似文献
18.
A technology of growing single crystals of (In2S3)
x
(MnIn2S4)1 − x
solid solutions that provides control over their atomic composition in the entire concentration range 0 ≤ x ≤ 1 is developed. It is shown that, in the range x = 0–1, the single crystals have the cubic spinel structure and the unit cell parameter a follows the linear dependence on x. The exponential character of the temperature dependence of resistivity of solid solutions, on which the first photosensitive
Cu/(In2S3)x(MnIn2S4)1 − x
structures are obtained, is revealed. The first photosensitivity spectra of these structures are obtained, and, based on
these spectra, dependences of energy of the direct and indirect band-to-band transitions on the composition x are determined. The possibility of applying these structures in broad-band photoconverters of optical radiation is concluded. 相似文献
19.
Complete mutual solubility in the (In2S3)
x
(FeIn2S4)1 − x
system is established. The technology is developed, and single crystals of the continuous series of the (In2S3)
x
(FeIn2S4)1 − x
solid solutions are grown for the first time. The linear dependence of the unit cell parameter of single crystals with a
cubic spinel lattice on the solid solution composition is found. First, photosensitive Schottky barriers are fabricated, and
then, based on studies of their photosensitivity, the character of band-to-band transition is discussed and the values of
the band gap depending on the atomic composition are estimated. The possibility of using the obtained solid solutions as broadband
photoconverters of optical radiation is revealed. 相似文献
20.
n-Type Bi2Te3−y
Se
y
thin films were prepared by potentiodynamic electrodeposition onto Au, Bi, and Bi2Te3−y
Se
y
substrates at room temperature. The electrochemical behaviors of Bi3+, HTeO2
+, and H2SeO3 on different substrates were investigated by cyclic voltammetry. The morphology, composition, and structure of the films
were studied by using environmental scanning electron microscopy (ESEM), energy-dispersive spectroscopy (EDS), and x-ray diffraction
(XRD), respectively. The thermoelectric properties of n-type Bi2Te3−y
Se
y
films were determined by measuring the Seebeck coefficient (α) and electrical resistivity (ρ). The results showed that the composition and morphology of the films were sensitive to the substrate material. X-ray diffraction
(XRD) analysis indicated that the preferred orientation of annealed films was affected by the substrate and that the film
prepared on the Bi2Te3−y
Se
y
substrate exhibited the strongest (015) orientation, with rhombohedral structure. It was proved that the properties of the
annealed films could be affected by the substrate and that the film with the highest power factor (P = α
2/ρ) was obtained on the Bi2Te3−y
Se
y
substrate. 相似文献