共查询到20条相似文献,搜索用时 78 毫秒
1.
J. Partyka P. W. Žukowski P. Wegierek A. Rodzik Yu. V. Sidorenko Yu. A. Shostak 《Semiconductors》2002,36(12):1347-1351
Electron spin resonance in semimagnetic Cd1?xMnxTe (0<x<0.7) and Zn1?xMnxTe (0<x<0.53) compounds was studied at temperatures of 77 and 300 K. It is found that two types of paramagnetic centers exist in Zn1?xMnxTe, one of which is related to Mn2+ ions and the other is attributed to structural defects in the crystals. 相似文献
2.
Dexuan Huo Guanghong Tang Chenguang Fu Lingwei Li 《Journal of Electronic Materials》2011,40(5):1202-1205
Polycrystalline samples of In4(Se1−x
Te
x
)3 were synthesized by using a melting–quenching–annealing process. The thermoelectric performance of the samples was evaluated
by measuring the transport properties from 290 K to 650 K after sintering using the spark plasma sintering (SPS) technique.
The results indicate that Te substitution can effectively reduce the thermal conductivity while maintaining good electrical
transport properties. In4Te3 shows the lowest thermal conductivity of all compositions tested. 相似文献
3.
P. A. Alekseev V. A. Sharov M. S. Dunaevskiy G. E. Cirlin R. R. Reznik V. L. Berkovits 《Semiconductors》2018,52(14):1833-1835
4.
The formation of a continuous series of substitutional solid solutions is theoretically considered from the viewpoint of taking into account generalized moments and differences in the valence and the covalent radii of atoms or molecules of initial components. These considerations are used to develop technology for the fabrication of (Si2)1?x(GaAs)x (0≤x≤0.96) and (Si2)1?x(GaP)x (0≤x≤1) epitaxial layers on silicon substrates from a tin melt-solution by the forced cooling method. The distribution of components over the thickness of the (Si2)1?x(GaAs)x and (Si2)1?x(GaP)x layers, the photosensitivity, and the current-voltage characteristics of Si-(Si2)1?x(GaAs)x and Si-(Si2)1?x(GaP)x heterostructures were studied. The analysis of results of X-ray investigations and photoelectric properties indicate that the grown epitaxial layers of (IV2)1?x(III-V)x solid solutions are structurally perfect. 相似文献
5.
I. V. Bodnar’ 《Semiconductors》2003,37(11):1247-1251
The optical and thermal properties of crystals of CuAlxIn1?xTe2 solid solutions grown by the Bridgman-Stockbarger method were studied for the first time. From the transmission and reflection spectra in the region of the intrinsic-absorption edge, the band gap (E g ) was determined for the CuInTe2 and CuAlTe2 compounds and for their solid solutions; the concentration dependence of E g was plotted. The E g value was found to vary nonlinearly with x and can be described by the quadratic dependence. Dilatometry was used to study the thermal expansion of these solid solutions. The coefficient of thermal expansion (αL) was shown to have a λ-shaped temperature dependence in the region of phase transitions. The isotherms are plotted for the concentration dependence of αL. The thermal conductivity was investigated and its concentration dependence was plotted. The dependence of the thermal conductivity on x was established to have a minimum in the region of medium compositions. 相似文献
6.
L. A. Kosyachenko A. V. Markov E. L. Maslyanchuk I. M. Rarenko V. M. Sklyarchuk 《Semiconductors》2003,37(12):1373-1379
The electrical characteristics of p-type Cd1?xZnxTe (x=0.05) and Cd1?xMnxTe (x=0.04) single crystals with a resistivity of 103–1010 Ω cm at 300 K are studied. The conductivity and its variation with temperature are interpreted on the basis of statistics of electrons and holes in a semiconductor with deep acceptor impurities (defects), with regard to their compensation by donors. The depth of acceptor levels and the degree of their compensation are determined. The problems of attaining near intrinsic conductivity close to intrinsic are discussed. 相似文献
7.
The transmittance spectra of single-crystal Cu2ZnSnS4 and Cu2ZnSnSe4 compounds and Cu2ZnSn(S x Se1–x )4 alloys grown by chemical vapor-transport reactions are studied in the region of the fundamental absorption edge. From the experimental spectra, the band gap of the compounds and their alloys is determined. The dependences of the band gap on the composition parameter x of the alloy are constructed. It is established that the band gap nonlinearly varies with x and can be described as a quadratic dependence. 相似文献
8.
I. V. Bodnar’ 《Semiconductors》2008,42(2):156-158
Coarse-grained crystals of AgGaSe2 and AgInSe2 ternary compounds and their alloys are grown by planar crystallization of the melts. For the crystals produced in this way, the transmittance spectra near the fundamental absorption edge are studied. From the experimental spectra, the band gap (E g) and its variation with composition are determined. It is established that E g is a nonlinear function of the composition parameter x. The dependence E g (x) is calculated theoretically in the context of the Van Vechten-Bergstresser model and Hill-Richardson pseudopotential model. 相似文献
9.
A. Chamoire F. Gascoin C. Estournès T. Caillat J.-C. Tédenac 《Journal of Electronic Materials》2010,39(9):1579-1582
Polycrystalline L4Sb3 (L = La, Ce, Sm, and Yb) and Yb4−x
Sm
x
Sb3, which crystallizes in the anti-Th3P4 structure type (I-43d no. 220), were synthesized via high-temperature reaction. Structural and chemical characterization were performed by x-ray
diffraction and electronic microscopy with energy-dispersive x-ray analysis. Pucks were densified by spark plasma sintering.
Transport property measurements showed that these compounds are n-type with low Seebeck coefficients, except for Yb4Sb3, which shows semimetallic behavior with hole conduction above 523 K. By partially substituting Yb by a trivalent rare earth
we successfully improved the thermoelectric figure of merit of Yb4Sb3 up to 0.7 at 1273 K. 相似文献
10.
Single crystals of the ternary system Bi2−x
Tl
x
Se3 (nominally x = 0.0 to 0.1) were prepared using the Bridgman technique. Samples with varying content of Tl were characterized by measurement
of lattice parameters, electrical conductivity σ
⊥c, Hall coefficient R
H(B║c), and Seebeck coefficient S(ΔT⊥c). The measurements indicate that incorporation of Tl into Bi2Se3 lowers the concentration of free electrons and enhances their mobility. This effect is explained within the framework of
the point defects in the crystal lattice, with formation of substitutional defects of thallium in place of bismuth (TlBi) and a decrease in the concentration of selenium vacancies (VSe + 2 V_{\rm{Se}}^{ + 2} ). The temperature dependence of the power factor σS
2 of the samples is also discussed. As a consequence of the thallium doping we observe a significant increase of the power
factor compared with the parent Bi2Se3. 相似文献
11.
V. Yu. Rud’ Yu. V. Rud’ V. F. Gremenok E. P. Zaretskaya O. N. Sergeeva 《Semiconductors》2005,39(9):1035-1039
p-Zn2?2xCuxInxSe2 (ZCIS) polycrystalline films 1–2 ¼m thick have been obtained by selenization. Photosensitive surface-barrier In/p-ZCIS structures are fabricated based on the films. The spectra of relative quantum efficiency of the structures obtained by selenization of the initial ZnSe/(Cu-In) and (Zn-Cu-In) films are examined. The optical band gap of the Zn2?2xCuxInxSe2 films is determined. Conclusions are reached on the prospects for the use of the obtained films as broadband photoconverters of natural optical radiation. 相似文献
12.
Optical reflectance spectra of (Pb0.78Sn0.22)1?xInxTe with a high indium content have been studied at T=300 K. Spectral features related to composition heterogeneity in the solid solutions were revealed. An assumption has been made that these heterogeneities are manifested as systems of ordered “threads.” Direct evidence of the existence of heterogeneities in (Pb0.78Sn0.22)1?xInxTe has been obtained by studying the surface morphology using optical and scanning electron microscopy. 相似文献
13.
Haijun Tang Chuanren Yang Jihua Zhang Hongwei Chen An Yu Wei He Yu Liao 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(7):852-857
A kind of distributed coplanar waveguide (CPW) phase shifter based on LaAlO3 substrates is designed and fabricated in this paper. The Ba0.4Sr0.6TiO3 (BST) thin films employed in the circuits are deposited by RF magnetron sputtering, and then annealed at 800°C for 30 min
in air. The dielectric tunability, loss tangent of the BST films are respectively 43.7% and 0.017 at 100 kHz and 30 V, the
leakage current is approximately 1 × 10−9A/cm2 at zero bias voltage. The CPW phase-shifter designed is subsequently fabricated in order to obtain a 360° phase shift at
30 GHz with a moderate bias voltage. The maximal phase shift is 372° at 22.5 GHz with a bias voltage of 40 V. 相似文献
14.
I. V. Bodnar 《Semiconductors》2010,44(5):581-584
The transmittance spectra of (CuInSe2)1 − x
(2MnSe)
x
alloy crystals grown by the Bridgman method are studied in the temperature range from 10 to 300 K. For these materials, the
band gap and its temperature dependence are determined. It is shown that the band gap decreases with increasing temperature.
The dependences of the band gap of the (CuInSe2)1 − x
(2MnSe)
x
alloys on the composition parameter x are plotted. 相似文献
15.
This study concerns the magnetic properties of single crystals of Fe
x
Mn1 − x
In2S4 alloys. The basically antiferromagnetic character of indirect exchange interactions between Fe2+ and Mn2+ cations is established. As the concentration of Fe2+ cations is increased, the magnetic ordering temperature increases from ∼12 K (x = 0) to ∼22 K (x = 1). Short-range-order ferromagnetic correlations are observed. The basic magnetic phase state of the alloys is the spin
glass state, with the freezing temperature increasing from ∼5 K (x = 0) to ∼12 K (x = 1). As the external magnetic field is increased, the magnetic ordering temperature slightly decreases. The most probable
causes and mechanisms of formation of the magnetic state of the alloys are discussed. 相似文献
16.
A series of compounds with composition Ag0.5In0.5−x
Pb5Sn4Te10 (x = 0.05 to 0.20) were prepared by slowly cooling the melts of the corresponding elements, and the effect of In content on the
thermoelectric transport properties of these compounds has been investigated. Results indicate that the compounds’ electronic
structure is sensitive to In content, and that the carrier concentration of these compounds at room temperature increases
from 4.86 × 1018 cm−3 to 3.85 × 1021 cm−3 as x increases from 0.05 to 0.20. For these compounds, electrical conductivity decreases and Seebeck coefficient increases with
increasing In content. Ag0.05In0.03Pb0.5Sn0.4Te10 shows very low lattice thermal conductivity, and has a maximum dimensionless figure of merit ZT of 1.2 at 800 K. 相似文献
17.
A. E. Kar’kin V. V. Shchennikov S. E. Danilov V. A. Arbuzov B. N. Goshchitskii 《Semiconductors》2003,37(11):1278-1282
In HgSe and HgSe1?xSx single crystals irradiated with electrons of 5 MeV energy at 270 K, resistivity and the Hall effect have been studied in the temperature range 1.7–370 K in magnetic field up to 13.6 T. Changes in the carrier density and mobility upon generation of radiation-induced defects and subsequent isochronous annealings have been determined. The irradiation made it possible to reduce the electron density to a greater extent than do conventional methods, as well as to restore the initial value by annealing. 相似文献
18.
O. K. Kuvandikov Kh. O. Shakarov Z. M. Shodiev A. Rustamov 《Journal of Communications Technology and Electronics》2007,52(9):1058-1061
For the first time, the Faraday method is used to measure the temperature dependence of paramagnetic susceptibility χ(T) of (La1 ? x Sr x )0.93MnO3 (x = 0.2, 0.25, or 0.3) manganites in the temperature interval 60–850°C. It is demonstrated that the dependences have two kinks and three linear sections. The kink of curve χ?1(T) is related to polymorphic transformations (Q′ → Q* and Q* → R) that take place in the crystal lattices of the samples. The main magnetic characteristics of the samples are determined with the least-squares processing of curve χ?1. Is is demonstrated that dependence χ?1(T) obeys the Curie-Weiss law. The energy state of the magnetoactive manganese atom in the Q′-and Q*-phase samples is close to the energy state of a free Mn2+ ion. In the R phase, this state is close to the state of a free Mn3+ ion. 相似文献
19.
Phonon spectra of (GaAs)n(Ga1?xAlxAs)m superlattices were calculated using the Keating model with allowance made for long-range forces. The calculated summed longitudinal acoustical branches are consistent with observed experimental Raman doublets. The tendency towards a shift to higher frequencies of longitudinal optical modes as the number of GaAs monolayers increases, which is observed both in calculations and in experiments, is caused by localization of these modes within the GaAs layer. 相似文献
20.
A. I. Voronin V. Yu. Zueva D. Yu. Karpenkov D. O. Moskovskikh A. P. Novitskii H. Miki V. V. Khovaylo 《Semiconductors》2017,51(7):891-893
Polycrystalline alloys Fe2TiSn1–x Si x (0 ≤ x ≤ 1) theoretically predicted as highly efficient thermoelectric materials are experimentally studied. Structural studies show that the partial substitution of Sn with Si results in the formation of a multiphase state in samples with x > 0. Impurity phases in general lead to a significant decrease in the Seebeck coefficient and an increase in the thermal conductivity of Fe2TiSn1–x Si x samples, which does not allow consideration of these materials as promising thermoelectrics. 相似文献