共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
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
3.
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
4.
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
5.
G. D. Tang C. P. Tang X. N. Xu Y. He L. Qiu L. Y. Lv Z. H. Wang Y. W. Du 《Journal of Electronic Materials》2011,40(5):504-507
The effects of Gd substitution on the thermoelectric (TE) properties of Ca3Co4O9+δ
have been systematically investigated from 25 K to 335 K. Partial substitution of Gd in Ca3Co4O9+δ
results in an increase of thermopower and resistivity, and a decrease of thermal conductivity. A maximum dimensionless figure
of merit (ZT) of 0.028 was achieved at 335 K for Ca2.4Gd0.6Co4O9+δ
, which is about one order of magnitude larger than that for Ca3Co4O9+δ
. The investigation demonstrates that the TE performance of the Ca3Co4O9+δ
system can be improved through Gd doping. 相似文献
6.
The I–V characteristics of the p-Si-n-(Si2) 1 − x
(CdS)
x
(0 ≤ x ≤ 0.01) structures are investigated at various temperatures. It is found that the I–V characteristic of such structures has a sublinear portion of the current growth with voltage V ≈ V
0exp(JaW). The experimental results can be explained on the basis of the theory of the injection depletion effect. It is shown that
the mobility of the minority carrier (hole) decreases with an increasing temperature.
Original Russian Text ? A.S. Saidov, A.Yu. Leyderman, Sh.N. Usmonov, K.T. Kholikov, 2009, published in Fizika i Tekhnika Poluprovodnikov,
2009, Vol. 43, No. 4, pp. 436–438. 相似文献
7.
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
8.
采用铌铁矿前驱体两步法制备了Pb(Zn1/3Nb2/3)0.2(Hf1-xTix)0.8O3(PZNH1-xTx)钙钛矿压电陶瓷,研究了铪钛比对陶瓷相结构、电学性能和能量收集特性的影响。结果表明,当x=0.52时,陶瓷样品位于准同型相界,具有最优综合压电性能:居里温度TC=287 ℃,品质因数FOM≈14 753×10-15 m2/N,压电电荷常数d33=492 pC/N。由该组成材料构建的悬臂梁型压电能量收集器输出功率密度高达4.16 μW/mm3,所转化的电能可成功点亮138盏并联的LED灯。结果表明,PZNHT陶瓷在压电能量收集领域具有良好的应用潜力。 相似文献
9.
Masayuki Hasaka Takao Morimura Hanae Sato Hiromichi Nakashima 《Journal of Electronic Materials》2009,38(7):1320-1325
Ribbons of Ti
x
(Hf
y
Zr1−y
)1−x
NiSn1−z
Sb
z
(x = 0.1 to 1, y = 0.1 to 0.9, z = 0, 0.002, 0.004) were prepared by spin casting and annealed for 1 h at T
a = 1000 K, 1050 K, 1073 K, and 1100 K. The crystal phase of the ribbons was investigated by x-ray diffraction analysis and
transmission electron microscopy. All the ribbons consisted of a phase with a half-Heusler structure. The Seebeck coefficient,
electrical conductivity, thermal conductivity, power factor, and figure of merit ZT at room temperature were clarified experimentally as a function of x, y, z, and T
a. Despite the large thermal conductivity, the power factor and figure of merit were remarkably large at x = 0.5, y = 0.5, z = 0.002, and T
a = 1073 K, because the Seebeck coefficient and electrical conductivity were large. 相似文献
10.
Z. F. Tomashik V. M. Tomashik I. B. Stratiychuk G. M. Okrepka I. I. Hnativ P. Moravec P. H?schl J. Bok 《Journal of Electronic Materials》2009,38(8):1637-1644
Chemical–mechanical polishing of CdTe and Zn
x
Cd1−x
Te single-crystal surfaces by bromine-evolving compositions based on aqueous solutions of H2O2(HNO3)–HBr–solvent has been investigated. The dependences of the chemical–mechanical polishing rate on the dilution of the base
polishing etchant for various organic components have been determined. The surface condition after such polishing has been
investigated using profilometry. The polishing etchant compositions for CdTe and Zn
x
Cd1−x
Te single-crystal surfaces and the chemical polishing conditions have been optimized. 相似文献
11.
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
12.
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
13.
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
14.
The field dependence of drift velocity of electrons in quantum wells of selectively doped In0.5Ga0.5As/Al
x
In1 − x
As and In0.2Ga0.8As/Al
x
Ga1 − x
As heterostructures is calculated by the Monte Carlo method. The influence of varying the molar fraction of Al in the composition
of the Al
x
Ga1 − x
As and Al
x
In1 − x
As barriers of the quantum well on the mobility and drift velocity of electrons in high electric fields is studied. It is
shown that the electron mobility rises as the fraction x of Al in the barrier composition is decreased. The maximum mobility in the In0.5Ga0.5As/In0.8Al0.2As quantum wells exceeds the mobility in a bulk material by a factor of 3. An increase in fraction x of Al in the barrier leads to an increase in the threshold field E
th of intervalley transfer (the Gunn effect). The threshold field is E
th = 16 kV/cm in the In0.5Ga0.5As/Al0.5In0.5As heterostructures and E
th = 10 kV/cm in the In0.2Ga0.8As/Al0.3Ga0.7As heterostructures. In the heterostructures with the lowest electron mobility, E
th = 2–3 kV/cm, which is lower than E
th = 4 kV/cm in bulk InGaAs. 相似文献
15.
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
16.
Gaurav Saraf Jian Zhong Olga Dulub Ulrike Diebold Theo Siegrist Yicheng Lu 《Journal of Electronic Materials》2007,36(4):446-451
The a-plane Mg
x
Zn1−x
O (0 ≤ x ≤ 0.3) films were grown on r-plane () sapphire substrates using metal-organic chemical vapor deposition (MOCVD). Growth was done at temperatures from 450°C to
500°C, with a typical growth rate of ∼500 nm/h. Field emission scanning electron microscopy (FESEM) images show that the films
are smooth and dense. X-ray diffraction (XRD) scans confirm good crystallinity of the films. The interface of Mg
x
Zn1−x
O films with r-sapphire was found to be semicoherent as characterized by high-resolution transmission electron microscopy (HRTEM). The Mg
x
Zn1−x
O surfaces were characterized using scanning tunneling microscopy (STM) in ultrahigh vacuum (UHV). Low-energy electron diffraction
(LEED) shows well-ordered and single-crystalline surfaces. The films have a characteristic wavelike surface morphology with
needle-shaped domains running predominantly along the crystallographic c-direction. Photoluminescence (PL) measurements show a strong near-band-edge emission without observable deep level emission,
indicating a low defect concentration. In-plane optical anisotropic transmission was observed by polarized transmission measurements. 相似文献
17.
分别利用因子群对称分析法和位置群对称分析法对Ca3(BO3)2晶体的振动模式进行了理论分析。Ca3(BO3)2的晶格振动模式分为外振动和内振动模式,外振动模式为:3A1g+4A2g+7Eg+3A1u+3A2u+6Eu,内振动模式为:2A1g+2A2g+4Eg+2A1u+2A2u+4Eu。Ca3(BO3)2晶体在布里渊区中心Γ点晶格振动的对称性分类为:5A1g+6A2g+11Eg+5A1u+6A2u+11Eu,其中声学模为:A2u+Eu,拉曼活性光学模为5A1g+11Eg,红外活性光学模为:5A2u+10Eu,其余为非拉曼、非红外活性光学振动模。用高温固相法成功合成了Ca3(BO3)2粉末,测量了它的室温Raman光谱,并利用群论分析的结果对谱图进行了讨论,指认了BO33-基团的特征振动频率。 相似文献
18.
Xueqin Zhao Jinou Dong Licheng Fu Yilun Gu Rufei Zhang Qiaolin Yang Lingfeng Xie Yinsong Tang Fanlong Ning 《半导体学报》2022,43(11):112501-1-112501-6
We report the successful synthesis and characterization of a novel 1111-type magnetic semiconductor (Ba1−xNax)F(Zn1−xMnx)Sb (0.05 ≤ x ≤ 0.175) with tetragonal ZrSiCuAs-type structure, which is isostructural to the layered iron-based superconductor La(O,F)FeAs. Na substitutions for Ba and Mn substitutions for Zn introduce carriers and local magnetic moments, respectively. Ferromagnetic interaction is formed when Na and Mn are codoped, demonstrating that local magnetic moments are mediated by carriers. Iso-thermal magnetization shows that the coercive field is as large as ~ 12 000 Oe, which is also reflected in the large split between the temperature-dependent magnetization in zero-field-cooling and field-cooling condition. AC susceptibility under zero field demonstrates that samples evolve into spin-glass state below spin freezing temperature Tf. The measurements of temperature-dependent resistivity indicate that (Ba1−xNax)F(Zn1−xMnx)Sb exhibits semiconducting behaviour. 相似文献
19.
Tran Dang Thanh Hoang Thanh Van The-Long Phan Seong-Cho Yu 《Journal of Electronic Materials》2014,43(4):1083-1090
Nanocomposite samples of (1 ? x)La0.7Ca0.3MnO3 + xLa1.5Sr0.5NiO4 (x = 0 to 0.3) were synthesized by a combination of the mechanical milling and solid-state reaction methods. X-ray diffraction analyses and magnetic measurements indicated that no reaction occurred between La0.7Ca0.3MnO3 (LCMO) and La1.5Sr0.5NiO4 (LSNO). The Curie temperature (T C) was almost independent of x, while the metal–insulator transition temperature (T MI) shifted from 251 K for x = 0.0 to 65 K for x = 0.2. The samples with x ≥ 0.25 exhibited insulating behavior in the temperature range from 30 K to 300 K. Addition of LSNO substantially increased the resistivity of the composites. This is attributed to enhanced magnetic disorder at LCMO grain boundaries due to the addition of LSNO. The temperature dependence of the resistivity, ρ(T), could be described by the phenomenological percolation model of phase segregation. Fitting the experimental ρ(T) data in the temperature range of 30 K to 300 K indicated that the activation energy of the composites increases as a function of the LSNO doping concentration (x). 相似文献
20.
采用高温固相法制备了Ca3Y2(Si3O9)2: Tb3+绿色荧光粉,研究了材料的光学性能。X 射线衍射(XRD)结果显示,掺杂少量的Tb3+,并未影响Ca3Y2(Si3O9)2材料 的晶相结构。Ca3Y2(Si3O9)2:Tb3+ 荧光粉的激发光谱由较强的4f75d1宽带吸收(200~300 nm )和较弱的4f-4f电子跃迁吸收 (300~500 nm)构成,主激发峰位于236nm。取波长分别为236、376和482nm的光 作为激发源时,发现样品的主发射峰均位于544 nm,对应Tb3+的5D 4→7F5跃迁发射。以236nm 紫外光作为激发源,监测544nm主发射峰,随Tb3+浓度 的增大,Ca3Y2(Si 3O9)2:Tb3+的荧光寿命逐渐减小,但在实验范围内并未出现浓度猝灭现象。 相似文献