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Balancing the contradictory relationship between thermoelectric parameters, such as effective mass and carrier mobility, is a challenge to optimize thermoelectric performance. Herein, the exceptional thermoelectric performance is realized in GeTe through collaboratively optimizing the carrier and phonon transport via stepwise alloying Pb and CuSbSe2. The formation energy of Ge vacancy is efficiently bolstered by alloying Pb, which reduces carrier density and carrier scattering to maintain superior carrier mobility in GeTe. Additionally, CuSbSe2, acting as an n-type dopant, further modulates carrier density and validly equilibrates carrier mobility and effective mass. Accordingly, the promising power factor of 45 µW cm−1 K−2 is achieved at 723 K. Meanwhile, point defects are found to significantly suppress phonons transport to descend lattice thermal conductivity by Pb and CuSbSe2 alloying, which barely impacts the carrier mobility. A combination with superior carrier mobility and lower lattice thermal conductivity, a maximum ZT of 2.2 is attained in Ge0.925Pb0.075Cu0.005Sb0.005TeSe0.01, which corresponds to a 100% promotion compared with that of intrinsic GeTe. This study provides a new indicator for optimizing carrier and phonon transport properties by balancing interrelated thermoelectric parameters. 相似文献
3.
The technological conditions for growing single crystals of Tl1–x In1–x Sn x Se2 (x = 0.1–0.25) alloys are developed. The spectral distribution of the photoconductivity of the grown crystals at T = 300 K and thermally stimulated conductivity are studied. The effect of In3+cation substitution with Sn4+ in Tl1–x In1–x Sn x Se2 (x = 0.1–0.25) alloys on their photoelectric properties is shown. 相似文献
4.
P. V. Seredin E. P. Domashevskaya I. N. Arsentyev D. A. Vinokurov A. L. Stankevich 《Semiconductors》2013,47(1):7-12
The growth of epitaxial Al x Ga1 ? x As:C alloys by metal-organic chemical vapor deposition (MOCVD) at low temperatures results in the formation of quaternary (Al x Ga1 ? x As)1 ? y C y alloys, in which carbon atoms can be concentrated at lattice defects in the epitaxial alloy with the formation of impurity nanoclusters. 相似文献
5.
S. I. Rembeza N. N. Kosheleva E. S. Rembeza T. V. Svistova E. Yu. Plotnikova E. Suvaci E. Özel G. Tuncolu C. Açiksari 《Semiconductors》2014,48(8):1118-1122
The study is concerned with high-purity SnO2 and ZnO powders produced from salt solutions of corresponding metals by low-temperature hydrothermal synthesis. Fragments of SnO2 and ZnO ceramic targets formed as 1 × 8 cm bars are fabricated by dry pressing. The bars are used to form composite targets for ion-beam sputtering and the fabrication of compositionally different (SnO2) x (ZnO)1 ? x (x = 1–0.5) films appropriate for the production of gas sensors or transparent electronic devices. The optical and electrical parameters of the films with different compositions are studied. 相似文献
6.
The effect of laser annealing on the photoluminescence properties of (SiC)1?x (AlN)x epitaxial films was studied. It was proposed that annealing causes the displacement of the Al and N atoms from their lattice sites and the formation of AlSi-NC donor-acceptor pairs acting as the luminescence centers. According to this model, the increase in the annealing time is accompanied by the formation of donor-acceptor pairs with the shortest interatomic distances at the expense of associations of the distant defects and by a shift of the respective photoluminescence band to the high-energy spectral region. 相似文献
7.
T. Kujofsa S. Cheruku W. Yu B. Outlaw S. Xhurxhi F. Obst D. Sidoti B. Bertoli P. B. Rago E. N. Suarez F. C. Jain J. E. Ayers 《Journal of Electronic Materials》2013,42(9):2764-2770
The design of lattice-mismatched semiconductor devices requires a predictive model for strains and threading dislocation densities. Previous work enabled modeling of uniform layers but not the threading dislocations in device structures with arbitrary compositional grading. In this work we present a kinetic model for lattice relaxation which includes misfit–threading dislocation interactions, which have not been considered in previous annihilation–coalescence models. Inclusion of these dislocation interactions makes the kinetic model applicable to compositionally graded structures, and we have applied it to ZnSe/GaAs (001) and ZnS y Se1?y /GaAs (001) heterostructures. The results of the kinetic model are consistent with the observed threading dislocation behavior in ZnSe/GaAs (001) uniform layers, and for graded ZnS y Se1?y /GaAs (001) heterostructures the kinetic model predicts that the threading dislocation density may be reduced by the inclusion of grading buffer layers employing compositional overshoot. This “dislocation compensation” effect is consistent with our high-resolution x-ray diffraction experimental results for graded ZnS y Se1?y /GaAs (001) structures grown by photoassisted metalorganic vapor-phase epitaxy. 相似文献
8.
Fu Cheng Wan Fu Ling Tang Zheng Xin Zhu Hong Tao Xue Wen Jiang Lu Yu Dong Feng Zhi Yuan Rui 《Materials Science in Semiconductor Processing》2013,16(6):1422-1427
We optimized the lattice structure of sulfur-doped CuInSe2 using first principles. The lattice constants for CuIn(SxSe1–x)2 vary linearly with x according to a(x)=–0.02828x+0.58786 nm and c(x)=–0.05692x+1.1834 nm, which agree well with experimental data. The optical properties of CuIn(SxSe1–x)2 were then systematically investigated using first-principles calculations with the HSE06 functional. We present data for the complex dielectric function, refractive index, extinction coefficient, reflectivity index, absorption coefficient, and optical bandgap for CuIn(SxSe1–x)2. The optical bandgap Eg obtained from the absorption coefficient is 1.07 eV for CuInSe2 and 1.384 eV for CuInS2. These values are very close to experimental results, indicating that first-principles calculations can yield accurate bandgap values. The optical bandgap of CuIn(SxSe1–x)2 increases linearly with the sulfur concentration according to Eg=0.3139x+1.0825 eV. 相似文献
9.
V. Yu. Rud’ Yu. V. Rud’ R. N. Bekimbetov V. F. Gremenok I. V. Bodnar’ L. V. Rusak 《Semiconductors》2000,34(5):558-562
Polycrystalline (CuInSe2)x(2ZnSe)1−x
films (x=0.6–1.0) with p-type conductivity and a thickness of 0.5–0.9 μm were obtained by pulsed laser evaporation. It is shown that a chalcopyrite-sphalerite
transition occurs in the above system for x=0.7. The obtained films were used to fabricate the photosensitive structure of the In/p-(CuInSe2)x(2ZnSe)1−x
and InSe(GaSe)/(CuInSe2)x(2ZnSe)1−x
types. Spectral dependences of photovoltaic-conversion quantum efficiency were studied, and the photosensitivity of the structures
in relation to the type of energy barrier and the composition was analyzed. It is concluded that the structures under consideration
can be used as broadband photovoltaic converters.
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Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 34, No. 5, 2000, pp. 576–581.
Original Russian Text Copyright ? 2000 by V. Rud’, Yu. Rud’, Bekimbetov, Gremenok, Bodnar’, Rusak. 相似文献
10.
Rutherford backscattering, IR spectroscopy, ellipsometry, and atomic-force microscopy are used to perform an integrated study of the composition, structure and optical properties of a-Si1 ? x C x :H〈Er〉 amorphous films. The technique employed to obtain the a-Si1 ? x C x :H〈Er〉 amorphous films includes the high-frequency decomposition of a mixture of gases, (SiH4) a + (CH4) b , and the simultaneous thermal evaporation of a complex compound, Er(pd)3. It is demonstrated that raising the amount of CH4 in the gas mixture results in an increase in the carbon content of the films under study and an increase in the optical gap E g opt from 1.75 to 2.2 eV. Changes in the composition of a-Si1 ? x C x :H〈Er〉 amorphous films, accompanied, in turn, by changes in the optical constants, are observed in the IR spectra. The ellipsometric spectra obtained are analyzed in terms of multiple-parameter models. The conclusion is made on the basis of this analysis that the experimental and calculated spectra coincide well when variation in the composition of the amorphous films with that of the gas mixture is taken into account. The existence of a thin (6–8 nm) silicon-oxide layer on the surface of the films under study and the validity of using the double-layer model in ellipsometric calculations is confirmed by the results of structural analyses by atomic-force microscopy. 相似文献
11.
Sushkov A. A. Pavlov D. A. Andrianov A. I. Shengurov V. G. Denisov S. A. Chalkov V. Yu. Kriukov R. N. Baidus N. V. Yurasov D. V. Rykov A. V. 《Semiconductors》2022,56(2):122-133
Semiconductors - III–V/Ge/Si(001), III–V/Ge/SOI(001), and III–V/GaAs(001) heterostructures are fabricated and investigated. The Ge buffer layer for the III–V/Ge/Si structure... 相似文献
12.
Yi Ma Waruna Wijesekara Anders E. C. Palmqvist 《Journal of Electronic Materials》2012,41(6):1138-1146
Thermoelectric thin films of the ternary compounds (Bi x Sb1?x )2Te3 and Bi2(Te1?y Se y )3 were synthesized using potentiostatic electrochemical deposition on gold-coated silicon substrates from aqueous acidic solutions at room temperature. The surface morphology, elemental composition, and crystal structure of the deposited films were studied and correlated with preparation conditions. The thermoelectric properties of (Bi x Sb1?x )2Te3 and Bi2(Te1?y Se y )3 films, i.e., Seebeck coefficient and electrical resistivity, were measured after transferring the films to a nonconductive epoxy support. (Bi x Sb1?x )2Te3 thin films showed p-type semiconductivity, and the highest power factor was obtained for film deposited at a relatively large negative potential with composition close to Bi0.5Sb1.5Te3. In addition, Bi2(Te1?y Se y )3 thin films showed n-type semiconductivity, and the highest power factor was obtained for film deposited at a relatively small negative potential, having composition close to Bi2Te2.7Se0.3. In contrast to Bi2Te2.7Se0.3 thin films, an annealing treatment was required for Bi0.5Sb1.5Te3 thin films to achieve the same magnitude of power factor as Bi2Te2.7Se0.3. Therefore, Bi2Te2.7Se0.3 thin films appear to be good candidates for multilayer preparation using electrochemical deposition, but the morphology of the films must be further improved. 相似文献
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14.
P. V. Seredin A. V. Glotov E. P. Domashevskaya A. S. Lenshin M. S. Smirnov I. N. Arsentyev D. A. Vinokurov A. L. Stankevich I. S. Tarasov 《Semiconductors》2012,46(6):719-729
The study is concerned with MOCVD epitaxial heterostructures grown on the basis of Al x Ga y In1 ? x ? y As z P1 ? z quinary alloys in the region of alloy compositions isoperiodic to GaAs. By the X-ray diffraction technique and atomic force microscopy, it is shown that, on the surface of the heterostructures, there are nanometric objects capable of lining up along a certain direction. From calculations of the crystal lattice parameters with consideration for internal strains, it can be inferred that the new compound is a phase based on the Al x Ga y In1 ? x ? y As z P1 ? z alloy. 相似文献
15.
Based on the empirical pseudo-potential method which incorporates compositional disorder as an effective potential, the band structure of Si1 ? x Ge x alloy are calculated for different alloy composition x. The effect of temperature and pressure on the electronic band structure of the considered alloy has been studied. Monotonic decreasing and increasing functions are obtained for the temperature and pressure dependent form factors respectively. Some physical quantities as band gaps, bowing parameters, and the refractive index of the considered alloy with different Ge concentration and under the effect of temperature and pressure are calculated. The results obtained are found in good agreement with the experimental and published data. 相似文献
16.
Alloys P. V. Seredin A. V. Glotov A. S. Lenshin I. N. Arsentyev D. A. Vinokurov Tatiana Prutskij Harald Leiste Monica Rinke 《Semiconductors》2014,48(1):21-29
Epitaxial heterostructures produced by MOCVD on the basis of Al x Ga1 ? x As ternary alloys with the composition parameter x ≈ 0.20–0.50 and doped to a high Si and P atomic content are studied. Using the high-resolution X-ray diffraction technique, scanning electron microscopy, X-ray microanalysis, Raman spectroscopy, and photoluminescence spectroscopy, it is shown that the epitaxial films grown by MOCVD are formed of five-component (Al x Ga1 ? x As1 ? y P y )1 ? z Si z alloys. 相似文献
17.
I. S. Vasil’evskii A. N. Vinichenko M. M. Grekhov V. P. Gladkov N. I. Kargin M. N. Strikhanov 《Semiconductors》2014,48(9):1226-1232
Graded In y Ga1 ? y As quantum well epitaxial technology is developed for engineering the band potential profile. The crystal structure of the samples is clarified by high-resolution X-ray diffraction. The influence of quantum-well bending on the crystal and electron transport properties is studied on one- and two-side δ-doped Al0.23Ga0.77As/In y Ga1 ? y As/Al0.23Ga0.77As PHEMT heterostructures. The highest InAs content gradient reached is 1.2%/nm for the mean InAs content y = 0. 2. Optimization of the InAs content grading leads to an increase in the electron mobility and concentration. This effect is related to the straightening and deepening of the quantum-well potential profile. In addition, the electron wavefunction shifts toward the quantum-well center, thus reducing electron scattering. 相似文献
18.
We have characterized the magnetic and structural properties of pure and 57Fe-doped La2/3Ca1/3MnO3 thin films and targets, substituted with 1% and 3% of 57Fe on the Mn site. The films were prepared via high O2-pressure (500 mTorr) by DC magnetron sputtering on (1 0 0) SrTiO3 and (1 0 0) LaAlO3 single-crystal substrates. Mössbauer spectra measured at room temperature confirm the presence of Fe3+ with octahedral coordination, thus indicating that Fe is incorporated into the structure by substituting Mn. Structural analysis by X-ray diffraction (XRD) shows that the films are single phase and c-axis oriented and that the Fe doping gives rise to a relaxation of the epitaxial strain. Interestingly, the Curie temperature and the magnetoresistance (MR) show a non-monotonic behavior with Fe doping. This indicates that initially the strain relaxation induced by the Fe doping is more important than the reduction of ferromagnetic coupling due to the Fe incorporation. 相似文献
19.
Seredin P. V. Domashevskaya E. P. Rudneva Val. E. Rudneva V. E. Gordienko N. N. Glotov A. V. Arsentyev I. N. Vinokurov D. A. Stankevich A. L. Tarasov I. S. 《Semiconductors》2009,43(9):1221-1225
The effect of instability of alloys of Ga
x
In1 − x
P/GaAs(100) semiconductor epitaxial heterostructures in the composition region x ≈ 0.50 is studied by X-ray diffraction and electron microscopy. The possibility of emergence of modulated relaxation structures
on the surface of a Ga
x
In1 − x
P alloy is shown. This phenomenon is accompanied by the emergence of satellites of main X-ray reflections corresponding to
a single-phase structure. 相似文献
20.
The temperature dependences of the Hall coefficient (4.2 K ≤ T ≤ 300 K, B ≤ 0.07 T) in Pb1 ? x ? y Ge x Cr y Te alloys (x = 0.03–0.08, y ≤ 0.01) are studied. An increase in the absolute value of the Hall coefficient with an increase in temperature is found. This fact is indicative of a decrease in the concentration of free electrons as a result of the motion of the resonant level of chromium stabilizing the Fermi level relative to the conduction-band bottom. The temperature dependences of the Hall coefficient, in satisfactory agreement with the experimental ones, are calculated in the context of the two-band Kane dispersion law allowing for the structural phase transition upon increasing temperature. The energy position and temperature coefficients of the motion of the resonant level of chromium relative to the middle of the band gap in the rhombohedral and cubic phases are determined. 相似文献