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1.
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
2.
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
3.
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
4.
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
5.
E. P. Domashevskaya N. N. Gordienko N. A. Rumyantseva B. L. Agapov P. V. Seredin L. A. Bityutskaya I. N. Arsentev L. S. Vavilova I. S. Tarasov 《Semiconductors》2008,42(9):1069-1075
Structural and optical properties of two- and three-layer epitaxial heterostructures containing GaInP/Ga
x
In1 − x
As
y
P1 − y
quaternary alloy layers were studied. Domain formation due to spinodal decomposition of the quaternary alloy was detected
in three-layer heterostructures. As a result, an additional long-wavelength band appears in the photoluminescence spectra,
and an additional doublet of the line appears in X-ray diffraction patterns of the (006) line. The domain composition was determined on the basis of Vegard’s
law and the Kouphal equation.
Original Russian Text ? E.P. Domashevskaya, N.N. Gordienko, N.A. Rumyantseva, B.L. Agapov, P.V. Seredin, L.A. Bityutskaya,
I.N. Arsent’ev, L.S. Vavilova, I.S. Tarasov, 2008, published in Fizika i Tekhnika Poluprovodnikov, 2008, Vol. 42, No. 9, pp.
1086–1093. 相似文献
6.
Enrico Furno Simone Chiaria Michele Penna Enrico Bellotti Michele Goano 《Journal of Electronic Materials》2010,39(7):936-944
As a preparatory step toward establishing reliable numerical design tools for ZnO-based optoelectronic devices, we have reassessed
the available information on material parameters relevant for the simulation of light-emitting diodes (LEDs) with active regions
including ZnO, MgZnO, and BeZnO layers. The impact of different approximations for the electronic structure and the interface
polarization charge on the optical properties of bulk ZnO and ZnO/MgZnO quantum wells has been evaluated, and a consistent
set of parameters has been used not only for systematic comparison of ZnO/MgZnO and ZnO/BeZnO single quantum well structures
but also for the first simulation of a realistic ZnO/BeZnO multiple quantum well LED. 相似文献
7.
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
8.
Fuad Al-Amoody Ernesto Suarez Angel Rodriguez E. Heller Wenli Huang F. Jain 《Journal of Electronic Materials》2011,40(8):1699-1705
This paper presents a floating quantum dot (QD) gate nonvolatile memory device using high-energy-gap Zn
y
Cd1−y
Se-cladded Zn
x
Cd1−x
Se quantum dots (y > x) with tunneling layers comprising nearly lattice-matched semiconductors (e.g., ZnS/ZnMgS) on Si channels. Also presented
is the fabrication of an electroluminescent (EL) device with embedded cladded ZnCdSe quantum dots. These ZnCdSe quantum dots
were embedded between indium tin oxide (ITO) on glass and a top Schottky metal electrode deposited on a thin CsF barrier.
These QDs, which were nucleated in a photo-assisted microwave plasma (PMP) metalorganic chemical vapor deposition (MOCVD)
reactor, were grown between the source and drain regions on a p-type silicon substrate of the nonvolatile memory device. The composition of QD cladding, which relates to the value of y in Zn
y
Cd1−y
Se, was engineered by the intensity of ultraviolet light, which controlled the incorporation of zinc in ZnCdSe. The QD quality
is comparable to those deposited by other methods. Characteristics and modeling of the II–VI quantum dots as well as two diverse
types of devices are presented in this paper. 相似文献
9.
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
10.
E. P. Skipetrov M. G. Mikheev F. A. Pakpour L. A. Skipetrova N. A. Pichugin E. I. Slyn’ko V. E. Slyn’ko 《Semiconductors》2009,43(3):297-304
Magnetic properties of Pb1 − x − y
Ge
x
Cr
y
Te alloys (x = 0.02–0.20, y = 0.01–0.08) were studied. It was detected that the magnetic susceptibility of alloys consists of two contributions: the
paramagnetic Curie-Weiss part (the temperature region is T < 50 K) caused, probably, by the Cr3+ ion paramagnetism, and the high-temperature ferromagnetic part (T < 300 K). The dependences of the concentration of magnetic centers on the composition of the matrix were obtained from the
paramagnetic and ferromagnetic contributions. It was shown that a decrease in the concentration of paramagnetic centers can
be, at least qualitatively, explained by the transformation of the electronic structure as the germanium concentration increases.
A phenomenological model was suggested, which explains the behavior of magnetic properties as the chromium content increases,
and possible mechanisms of ferromagnetic ordering in studied alloys are discussed.
Original Russian Text ? E.P. Skipetrov, M.G. Mikheev, F.A. Pakpour, L.A. Skipetrova, N.A. Pichugin, E.I. Slyn’ko, V.E. Slyn’ko,
2009, published in Fizika i Tekhnika Poluprovodnikov, 2009, Vol. 43, No. 3, pp. 316–323. 相似文献
11.
H. von Wenckstern K. Brachwitz M. Schmidt C. P. Dietrich M. Ellguth M. St?lzel M. Lorenz M. Grundmann 《Journal of Electronic Materials》2010,39(5):584-588
The authors used highly rectifying PdO
y
/Mg
x
Zn1−x
O Schottky barriers to determine the apparent capture cross-section and the thermal activation energy of the E3 defect in
Mg
x
Zn1−x
O thin films by thermal admittance spectroscopy and deep-level transient spectroscopy for x < 0.08. The samples were grown by pulsed-laser deposition. It is observed that both the apparent capture cross-section and
the thermal activation energy increase with increasing Mg mole fraction. 相似文献
12.
The influence of temperature and Ga composition on Auger recombination lifetime in n-type and p-type In1-xGaxAs materials is investigated through the simulation, assuming the concentrations of electrons and holes are 1017 cm-3 and 1018 cm-3, respectively. The results show that the temperature has little influence on Auger recombination lifetime of In1-xGaxAs materials at x<0.3. However, it has a great impact when x>0.3 and the effect is more obvious at a lower temperature. Moreover, Auger ... 相似文献
13.
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
14.
The influence of hydrogenation on the electrical properties of the CdxHg1 ? xTe epitaxial structures
V. S. Varavin G. Yu. Sidorov M. O. Garifullin A. V. Vishnyakov Yu. G. Sidorov 《Semiconductors》2011,45(3):397-402
The phenomenon of hydrogenation of the Cd
x
Hg1 − x
Te films is studied. Hydrogenation was performed via either boiling the Cd
x
Hg1 − x
Te films in deionized water or using the electrochemical treatment. It is established that, during contacts with aqueous media,
the acceptor centers are introduced into the films; their concentration can exceed 1017 cm−3. It is shown that two types of hydrogen-based acceptors are introduced, namely, fast and slow acceptors, and their diffusivities
are evaluated. It is found that hydrogen partially exists after treatment in an electrically inactive form and can be activated
with further storage or during heating. After activation, the hole concentration can become as high as 1018 cm−3. The influence of pH of the medium on the rate of introduction of hydrogen into the material is discussed. 相似文献
15.
The photoluminescence spectra of the Pb1 − x
Eu
x
Te (0 ≤ x ≤ 0.1) alloy are studied at low temperatures. Epitaxial layers were grown by molecular-beam epitaxy at different temperatures.
Along with the basic line corresponding to interband radiative recombination, additional emission lines are observed in the
low-energy region of the spectra. Some nonuniformities are observed at the sample surface (within an area smaller than 1%
of the total surface area). The concentration and size (1–10 μm) of the nonuniformities decrease with increasing temperature
of growth. The additional emission lines are attributed to local nonuniformities in the layer. The dependence of the band
gap of the Pb1−x
Eu
x
Te (0 ≤ x ≤ 0.1) alloy on the composition parameter x is determined at 77.4 K. The dependence is nonlinear and adequately described by the relation E
g
[eV] = 0.213 + 4.8x − 18.4x
2. 相似文献
16.
D. A. Pashkeev Yu. G. Selivanov E. G. Chizhevskii D. B. Stavrovskii I. I. Zasavitskiy 《Semiconductors》2011,45(8):980-987
The transmittance spectra of epitaxial Pb1 − x
Eu
x
Te (0 ≤x ≤ 0.1) alloy layers are exploited to study the dispersion of their refractive index in the spectral range from 650 to 8000
cm−1 (below the absorption edge). The refractive index and the position of the absorption edge as functions of the composition
parameter of the alloys are determined at two temperatures, 80 and 295 K. The refractive index is calculated in the context
of the classic wave concepts of propagation of electromagnetic radiation. The experimentally determined dispersion dependences
are described by the empiric Sellmeier expression of the second order. From analysis of the transmittance of the layers, it
follows that the band gap of the epitaxial Pb1 − x
Eu
x
Te alloys increases with increasing temperature at x < 0.5 and decreases at x > 0.5. 相似文献
17.
18.
Design of GaAs/AlxGa1?xAs asymmetric quantum wells for THz-wave by difference frequency generation
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The energy levels, wave functions and the second-order nonlinear susceptibilities are calculated in GaAs/Al0.2Ga0.8As/Al0.5Ga0.5As asymmetric quantum well (AQW) by using an asymmetric model based on the parabolic and non-parabolic band. The influence of non-parabolicity can not be neglected when analyzing the phenomena in narrow quantum wells and in higher lying subband edges in wider wells. The numerical results show that under double resonance (DR) conditions, the second-order difference frequency generation (DFG) and optical rectification (OR) generation susceptibilities in the AQW reach 2.5019 mm/V and 13.208 mm/V, respectively, which are much larger than those of the bulk GaAs. Besides, we calculate the absorption coefficient of AQW and find out the two pump wavelengths correspond to the maximum absorption, so appropriate pump beams must be selected to generate terahertz (THz) radiation by DFG. 相似文献
19.
Within the effective-mass approximation, we calculated the influence of strain on the binding energy of a hydrogenic donor
impurity by a variational approach in a cylindrical wurtzite GaN/Al
x
Ga1−x
N strained quantum dot, including the strong builtin electric field effect due to the spontaneous and piezoelectric polarization.
The results show that the binding energy of impurity decreases when the strain is considered. Then the built-in electric field
becomes bigger with the Al content increasing and the binding energy of hydrogenic donor impurity decreases when the Al content
is increasing. For dot height L < 2 nm, the change of the binding energy is very small with the Al content variety.
This work has been supported by the National Natural Science Foundation of China (No. 10564003) and the Key Project of the
Science and Technology Research of the Educational Ministry of China (No. 208025) 相似文献
20.
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