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1.
A comparative analysis of dielectric polarization processes in undoped and Bi-doped layers of modified As2Se3 has been performed. It is established that both the similarity and difference in polarization phenomena are due to specific
features of the internal structure of studied materials. The mechanism of the observed effects is discussed. 相似文献
2.
I. V. Bodnar’ E. S. Dmitrieva S. E. Nikitin V. Yu. Rud’ Yu. V. Rud’ E. I. Terukov 《Semiconductors》2005,39(4):402-405
n-ZnO:Al/PdPc/p-CuIn3Se5 photosensitive structures have been proposed and fabricated for the first time by vacuum sublimation of palladium phthalocyanine on the surface of wafers of the ternary semiconductor compound CuIn3Se5 and by magnetron sputtering of n-ZnO:Al films on the surface of palladium phthalocyanine films. The current-voltage characteristics and spectra of the photoconversion quantum efficiency of the obtained structures are investigated. It is shown that these structures can be used as multiband white-light converters. 相似文献
3.
Jae-Hong Lim Mi Yeong Park Dong Chan Lim Bongyoung Yoo Jung-Ho Lee Nosang V. Myung Kyu Hwan Lee 《Journal of Electronic Materials》2011,40(5):1321-1325
Thermoelectric Sb
x
Te
y
films were potentiostatically electrodeposited in aqueous nitric acid electrolyte solutions containing different concentrations
of TeO2. Stoichiometric Sb
x
Te
y
films were obtained by applying a voltage of −0.15 V versus saturated calomel electrode (SCE) using a solution consisting
of 2.4 mM TeO2, 0.8 mM Sb2O3, 33 mM tartaric acid, and 1 M HNO3. The nearly stoichiometric Sb2Te3 films had a rhombohedral structure, R[`3]m R\bar{3}m , with a preferred orientation along the (015) direction. The films had hole concentration of 5.8 × 1018/cm3 and exhibited mobility of 54.8 cm2/Vs. A more negative potential resulted in higher Sb content in the deposited Sb
x
Te
y
films. Furthermore, it was observed that the hole concentration and mobility decreased with increasingly negative deposition
potential, and eventually showed insulating properties, possibly due to increased defect formation. The absolute value of
the Seebeck coefficient of the as-deposited Sb2Te3 thin film at room temperature was 118 μV/K. 相似文献
4.
V. A. Terekhov E. I. Terukov Yu. K. Undalov E. V. Parinova D. E. Spirin P. V. Seredin D. A. Minakov E. P. Domashevskaya 《Semiconductors》2016,50(2):212-216
The phase composition and optical properties of hydrogenated amorphous films of silicon suboxide (a-SiOx:H) with silicon nanoclusters are studied. Ultrasoft X-ray emission spectroscopy show that silicon- suboxide films with various oxidation states and various amorphous silicon-cluster contents can be grown using dc discharge modulation. In films with an ncl-Si content of ~50%, the optical-absorption edge is observed, whose extrapolation yields an optical band gap estimate of ~3.2–3.3 eV. In the visible region, rather intense photoluminescence bands are observed, whose peak positions indicate the formation of silicon nanoclusters 2.5–4.7 nm in size in these films, depending on the film composition. 相似文献
5.
A. O. Evwaraye 《Journal of Electronic Materials》2010,39(6):751-755
n-Type 4H-SiC bulk samples with a net doping concentration of 2.5 × 1017 cm−3 were irradiated at room temperature with 1-MeV electrons. The high doping concentration plus a reverse bias of up to −13 V
ensures high electric field in the depletion region. The dependence of the emission rate on the electric field in the depletion
region was measured using deep-level transient spectroscopy (DLTS) and double-correlation deep-level transient spectroscopy
(DDLTS). The experimental data are adequately described by the phonon-assisted tunneling model proposed by Karpus and Pere. 相似文献
6.
Evandro Daniel Calderaro Cotrim Luís Henrique de Carvalho Ferreira 《Analog Integrated Circuits and Signal Processing》2012,71(2):275-282
In this paper an ultra-low-power CMOS symmetrical operational transconductance amplifier (OTA) for low-frequency G
m
-C applications in weak inversion is presented. Its common mode input range and its linear input range can be made large using
DC shifting and bulk-driven differential pair configuration (without using complex approaches). The symmetrical OTA was successfully
verified in a standard CMOS 0.35-μm process. The measurements show an open loop gain of 61 dB and a unit gain frequency of
195 Hz with only 800 mV of power supply voltage and just 40 nW of power consumption. The transconductance is 66 nS, which
is suitable for low-frequency G
m
-C applications. 相似文献
7.
V. V. Brus M. I. Ilashchuk Z. D. Kovalyuk P. D. Maryanchuk K. S. Ulyanytsky B. N. Gritsyuk 《Semiconductors》2011,45(8):1077-1081
Surface-barrier anisotype n-TiO2/p-CdTe heterojunctions are fabricated by depositing thin titanium-dioxide films on a freshly cleaved surface of single-crystalline
cadmium-telluride wafers by reactive magnetron sputtering. It is established that the electric current through the heterojunctions
under investigation is formed by generation-recombination processes in the space-charge region via a deep energy level and
tunneling through the potential barrier. The depth and nature of the impurity centers involved in the charge transport are
determined. 相似文献
8.
Yu. M. Isaenko 《Journal of Communications Technology and Electronics》2009,54(1):27-39
The excitation of main parasitic modes E 11, H 11, and H 21, which have cutoff sections in a sectoral transition between modes H 10 and H 01, is investigated. It is shown that, for magnetic modes, including modes H 11 and H 21, it is unnecessary to use the Airy equation and that this circumstance simplifies the design relationships. The energies of these modes are calculated as functions of the transition parameters. 相似文献
9.
N. T. Bagraev L. E. Klyachkin A. M. Malyarenko A. I. Ryskin A. S. Shcheulin 《Semiconductors》2005,39(5):528-532
Boron diffusion and the vapor-phase deposition of silicon layers are used to prepare ultrashallow p+-n junctions and p+-Si-n-CdF2 heterostructures on an n-CdF2 crystal surface. Forward portions of the I–V characteristics of the p+-n junctions and p+-Si-n-CdF2 heterojunctions reveal the CdF2 band gap (7.8 eV), as well as allow the identification of the valence-band structure of cadmium fluoride crystals. Under conditions in which forward bias is applied to the p+-Si-n-CdF2 heterojunctions, electroluminescence spectra are measured for the first time in the visible spectral region. 相似文献
10.
For approximating the insignificant deviation of the axes of radiating optical dipoles of VGaTeAs complexes in GaAs from one of the 〈111〉 directions, the shape of the structureless photoluminescence band of these defects at a pressure of 10 kbar along the [111] axis is analyzed. For separating split components of this band, which belong to centers with different orientations, a procedure is developed which uses the laws of the piezospectroscopic behavior of anisotropic centers. According to this procedure, spectral measurements are carried out when the electric vector of the optical wave is either parallel or normal to the pressure axis. The model suggested for analysis is verified. It is determined that the splitting of the energies of the centers with different orientations at a pressure of 10 kbar is approximately equal to 38 meV. In this case, the relative fraction of the rotator that describes the polarization properties of light emitted by an individual complex in a classical dipole approximation is equal to 0.15. This fact is indicative of the comparability of the roles of spin-orbit and Jahn-Teller interactions in the formation of the emitting state of the complex. 相似文献
11.
The temperature dependences of significant energy extrema at the high-symmetry points Γ, X, L, K, M, A, and H of the Brillouin zone in the cubic and hexagonal modifications of SiC, as well as the energies of the main interband transitions at these points, were calculated for the first time by the empirical-pseudopotential method. The effect of the temperature dependence of the electron-phonon interaction on the crystal band structure was taken into account via the Debye-Waller factors, and the contribution of the linear expansion of the lattice was accounted for via the temperature dependence of the linear-expansion coefficient. The special features of the temperature dependences of the energy levels and of energies of the interband and intraband transitions are analyzed in detail. The results of the calculations are in good agreement with the known experimental data on the characteristics of SiC-based p-n structures operating in the breakdown mode. For example, the temperature coefficient of the energy of the X1c–X3c transition, which is responsible for the narrow violet band in the breakdown-electroluminescence spectra of reverse-biased p-n junctions, was found to be significantly smaller than the temperature coefficients for the interband transitions (from the conduction to valence band). This fact is quite consistent with the experimental curve of the temperature coefficient of the emission spectrum, which has a minimum in the same wavelength range. 相似文献
12.
Y. Chen T. J. Zhu S. H. Yang S. N. Zhang W. Miao X. B. Zhao 《Journal of Electronic Materials》2010,39(9):1719-1723
A new preparation process combining melt spinning and hot pressing has been developed for the (Ag
x
SbTe
x/2+1.5)15(GeTe)85 (TAGS-85) system. Compared with samples prepared by the traditional air-quenching and hot-pressing method, electrical conductivity
and thermal conductivity are lowered. The thermoelectric performance of the TAGS-85 samples varied with changing Ag content
and reached the highest ZT of 1.48 when x was 0.8 for the melt-spun sample, compared with the maximum ZT of 1.36 for the air-quenched sample. The Seebeck coefficient of the melt-spun TAGS-85 alloys was improved, while both the
electrical conductivity and thermal conductivity were decreased. The net result of this process is to effectively enlarge
the temperature span of ZT > 1, which will benefit industrial application. 相似文献
13.
S. Y. Wang W. J. Xie H. Li X. F. Tang Q. J. Zhang 《Journal of Electronic Materials》2011,40(5):1150-1157
A series of Bi2(Se0.4Te0.6)3 compounds were synthesized by a rapid route of melt spinning (MS) combined with a subsequent spark plasma sintering (SPS)
process. Measurements of the Seebeck coefficient, electrical conductivity, and thermal conductivity were performed over the
temperature range from 300 K to 520 K. The measurement results showed that the cooling rate of melt spinning had a significant
impact on the transport properties of electrons and phonons, effectively enhancing the thermoelectric properties of the compounds.
The maximum ZT value reached 0.93 at 460 K for the sample prepared with the highest cooling rate, and infrared spectrum measurement results
showed that the compound with lower tellurium content, Bi2(Se0.4Te0.6)3, possesses a larger optical forbidden gap (E
g) compared with the traditional n-type zone-melted material with formula Bi2(Se0.07Te0.93)3. Our work provides a new approach to develop low-tellurium-bearing Bi2Te3-based compounds with good thermoelectric performance. 相似文献
14.
Electrical properties of a p+-Bi2Te3-p-GaSe isotype heterostructure fabricated for the first time are reported. A qualitative model is suggested which explains the emergence of negative differential conductivity for a forward-biased structure and for a reverse-biased structure, which is also illuminated. 相似文献
15.
A. A. Lebedev A. M. Strel’chuk D. V. Davydov N. S. Savkina A. S. Tregubova A. N. Kuznetsov V. A. Solov’ev N. K. Poletaev 《Semiconductors》2003,37(4):482-484
Sublimation epitaxy in a vacuum has been employed to grow n-and p-type 3C-SiC layers on 6H-SiC substrates. Diodes have been fabricated on the basis of the p-n structure obtained, and their parameters have been studied by measuring their current-voltage and capacitance-voltage characteristics and by applying the DLTS and electroluminescence methods. It is shown that the characteristics of the diodes studied are close to those of diodes based on bulk 3C-SiC. A conclusion is made that sublimation epitaxy can be used to fabricate 3C-SiC p-n structures on substrates of other silicon carbide polytypes. 相似文献
16.
Siham Benkouda Mounir Amir Tarek Fortaki Abdelmadjid Benghalia 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(11):1350-1366
The dual-frequency behavior of stacked high T
c
superconducting rectangular microstrip patches fabricated on a two-layered substrate is investigated using a full-wave spectral
analysis in conjunction with the complex resistive boundary condition. Using a matrix representation of each layer, the dyadic
Green’s functions of the problem are efficiently determined in the vector Fourier transform domain. The stationary phase method
is used for computing the radiation electric field of the antenna. The proposed approach is validated by comparison of the
computed results with previously published data. Variations of the lower and upper resonant frequencies, bandwidth and quality
factor with the operating temperature are given. Results showing the effects of the bottom patch thickness as well as the
top patch thickness on the dual-frequency behavior of the stacked configuration are also presented and discussed. Finally,
for a better comprehension of the dual-frequency operation, a comparison between the characteristics of the lower and upper
resonances is given. 相似文献
17.
Synthesis and also the structural and photoluminescence properties of nanocrystals with natural faceting of the “cesium–lead–halogen” system with crystalline structure of the perovskite type are examined. The possibility of continuously changing the position of the maximum in the photoluminescence spectrum in the wavelength range of 400–700 nm is demonstrated. Features of the formation of the continuous series of solid solutions CsPb(Cl1–x Br x )3 and CsPb(Br1–x I x )3 due to the aftergrowth treatment of CsPbBr3 nanocrystals as a result of anion exchange at room temperature are studied. The corresponding range of frequency change for the maximum of the photoluminescence spectrum amounts to 410–690 nm. 相似文献
18.
M. N. Solovan A. I. Mostovyi V. V. Brus E. V. Maistruk P. D. Maryanchuk 《Semiconductors》2016,50(8):1020-1024
n-TiN/p-Hg3In2Te6 heterostructures are fabricated by depositing a thin n-type titanium nitride (TiN) film onto prepared p-type Hg3In2Te6 plates using reactive magnetron sputtering. Their electrical and photoelectric properties are studied. Dominant charge-transport mechanisms under forward bias are analyzed within tunneling-recombination and tunneling models. The fabricated n-TiN/p-Hg3In2Te6 structures have the following photoelectric parameters at an illumination intensity of 80 mW/cm2: the open-circuit voltage is VOC = 0.52 V, the short-circuit current is ISC = 0.265 mA/cm2, and the fill factor is FF = 0.39. 相似文献
19.
E. V. Burmistrov V. Yu. Slobodchikov V. V. Khanin Yu. V. Maslennikov O. V. Snigirev 《Journal of Communications Technology and Electronics》2008,53(10):1259-1265
SQUID electronics optimized for operation in unshielded space with dc high-T c superconducting quantum interference devices (HTS SQUIDs) are developed, manufactured, and studied. The dynamic characteristics of the SQUID electronics are studied with two magnetic-field sensors based on the HTS SQUIDs: a conventional SQUID sensor with a resolution of 100 fT/Hz1/2 and a supersensitive SQUID sensor with a resolution of 15 fT/Hz1/2 at frequencies exceeding 10 Hz and a resolution of 30 fT/Hz1/2 at a frequency of 1 Hz. Stable operation of the magnetometric channel is demonstrated with both SQUID sensors under urban conditions. On the basis of a complex programmable logic device (CPLD), an ac bias can be realized in the SQUID and the modulation signal can be compensated in the feedback, bias-current, and desired-signal circuits. Such a compensation system is the most appropriate and versatile means of providing stable operation of the magnetometric channel in the presence of the SQUID ac bias, regardless of the type of high-temperature sensor and the configuration of the input contacts in the measurement probe. 相似文献
20.
V. G. Baru S. Bayliss V. A. Zhitov L. Yu. Zakharov G. Kartopu V. I. Pokalyakin A. Sapelkin G. V. Stepanov A. A. Timofeev O. F. Shevchenko 《Russian Microelectronics》2005,34(5):272-278
With a view to creating Si LEDs, the structural and luminescent properties of SiO x N y films containing Si nanocrystals in the SiO x N y matrix are studied experimentally. It is found that the film structure (nanocrystal size and concentration, the presence of an amorphous phase, etc.) and the spectrum and intensity of photoluminescence (PL) and electroluminescence (EL) are strongly dependent on the Si stoichiometric excess δ and annealing conditions. At δ≈ 10%, unannealed films are amorphous and contain Si clusters of size < 2 nm, as deduced from the TEM and microdiffraction data obtained. Annealing at 800–1000°C for 10–60 min produces Si crystals 3–5 nm in size with a concentration of ≈1018 cm?3. The annealed films exhibit room-temperature PL and EL over the wavelength range 400–850 nm with intensity peaks located at 50–60 and 60–70 nm, respectively. The PL and EL spectra are found to be qualitatively similar. This suggests that both the PL and the EL should be associated with the formation of luminescent centers at nanocrystal–matrix interfaces and in boundary regions. However, the two phenomena should differ in the mechanism by which the centers are excited. With the EL, excitation should occur by impact processes due to carrier heating in high electric fields. It is found that as δ increases, so does the proportion of large amorphous Si clusters with a high density of dangling bonds. This enhances nonradiative recombination and suppresses luminescence. 相似文献