共查询到20条相似文献,搜索用时 31 毫秒
1.
I. Z. Indutnyy I. Yu. Maĭdanchuk V. I. Min’ko P. E. Shepelyavyĭ V. A. Dan’ko 《Semiconductors》2007,41(10):1248-1254
The effect of chemical treatment in saturated vapors of ammonia and acetone on the spectral composition and intensity of photoluminescence in porous SiO x films containing Si nanocrystals (nc-Si) is studied. The porosity of the SiO x films is provided by oblique vacuum deposition of thermally evaporated silicon or silicon monoxide on polished silicon substrates. The kinetics of adsorption of the vapors is monitored by variations in the frequency of a quartz oscillator on which the films to be studied are deposited. As a result of chemical treatment followed by high-temperature annealing of the SiO x films at the temperature 950°C, a new band, absent from the as-prepared films, appears in the photoluminescence spectrum at shorter wavelengths. The peak position and intensity of the band depend, correspondingly, on the composition of the film and on the time duration of the treatment. It is found that the new photoluminescence band is quenched upon exposure to laser radiation at the wavelength 488 nm. The quenching is more pronounced at the band peak. The possibility of controlling the characteristics of photoluminescence of the porous structures by chemical treatment is shown. 相似文献
2.
S. E. Nikitin V. N. Verbitskiy A. V. Nashchekin I. N. Trapeznikova A. V. Bobyl E. E. Terukova 《Semiconductors》2017,51(1):104-109
The process of surface texturing of single-crystal silicon oxidized under a V2O5 layer is studied. Intense silicon oxidation at the Si–V2O5 interface begins at a temperature of 903 K which is 200 K below than upon silicon thermal oxidation in an oxygen atmosphere. A silicon dioxide layer 30–50 nm thick with SiO2 inclusions in silicon depth up to 400 nm is formed at the V2O5–Si interface. The diffusion coefficient of atomic oxygen through the silicon-dioxide layer at 903 K is determined (D ≥ 2 × 10–15 cm2 s–1). A model of low-temperature silicon oxidation, based on atomic oxygen diffusion from V2O5 through the SiO2 layer to silicon, and SiO x precipitate formation in silicon is proposed. After removing the V2O5 and silicon-dioxide layers, texture is formed on the silicon surface, which intensely scatters light in the wavelength range of 300–550 nm and is important in the texturing of the front and rear surfaces of solar cells. 相似文献
3.
The aim of this study, to explain effects of the SiO2 insulator layer thickness on the electrical properties of Au/n-GaAs Shottky barrier diodes (SBDs). Thin (60 Å) and thick (250 Å) SiO2 insulator layers were deposited on n-type GaAs substrates using the plasma enganced chemical vapour deposition technique. The current-voltage (I–V) and capacitance-voltage (C-V) characteristics have been carried out at room temperature. The main electrical parameters, such as ideality factor (n), zero-bias barrier height (? Bo ), series resistance (R s ), leakage current, and interface states (N ss ) for Au/SiO2/n-GaAs SBDs have been investigated. Surface morphologies of the SiO2 dielectric layer was analyzed using atomic force microscopy. The results show that SiO2 insulator layer thickness very affects the main electrical parameters. Au/n-GaAs SBDs with thick SiO2 insulator layer have low leakage current level, small ideality factor, and low interface states. Thus, Au/n-GaAs SBDs with thick SiO2 insulator layer shows better diode characteristics than other. 相似文献
4.
M. D. Efremov V. A. Volodin D. V. Marin S. A. Arzhannikova G. N. Kamaev S. A. Kochubeĭ A. A. Popov 《Semiconductors》2008,42(2):202-207
Using optical methods, data on optical constants are obtained for silicon nitride films synthesized by plasma-chemical vapor deposition (PCVD). Models for calculating the permittivity in the model of inhomogeneous phase mixture of silicon and silicon nitride are considered. It is found that the optical-absorption edge (E g) and the photoluminescence peak shift to longer wavelengths with increasing nitrogen atomic fraction x in sin x films. When x approaches the value 4/3 characteristic for stoichiometric silicon nitride Si3N4, a nonlinear sharp increase in E g is observed. Using Raman scattering, Si-Si bonds are revealed, which confirms the direct formation of silicon clusters during the film deposition. The relation between the composition of nonstoichiometric silicon nitride films, values of permittivity, and the optical-band width is established for light transmission. 相似文献
5.
The photoluminescence properties of thallium-containing vitreous semiconductor systems with stoichiometric and nonstoichiometric compositions (GeSe2)1–x Tl x and (GeSe3)1–x Tl x (0 ? x ? 0.1) are studied at a temperature of T = 77 K. Intrinsic defects with negative correlation energy are responsible for the Gaussian shape of the photoluminescence spectra. It is established that an increase in x in the systems does not affect the shape of the spectrum, does not generate new emission bands, shifts the photoluminescence spectra to the region of low energies, reduces the intensity of radiation, and increases its half-width. Kinetics of the fatigue of photoluminescence is different for both systems and is characterized by one curve irrespective of Tl content in the systems. 相似文献
6.
A. S. Dzhumaliev Yu. V. Nikulin Yu. A. Filimonov 《Journal of Communications Technology and Electronics》2009,54(3):331-335
For polycrystalline films of cobalt that have the thickness t ≈ 1.3–133 nm and that are deposited via DC magnetron sputtering on SiO2(0.1 μm)/Si(100) substrates, surface-roughness root-mean-square amplitude σ and surface correlation length ξ, which characterize the roughness of film surfaces, as well as saturation magnetization 4πM 0, width of ferromagnetic-resonance line ΔH, coercitivity H C, and saturation fields H S, are studied as functions of film thickness t. It is shown that the behavior of dependences H C(t) and H S(t) coincides with the behavior of dependence σ(t)/t, whereas the behavior of 4πM 0(t) depends on ratio t/σ(t). The dependence of the FMR line width on the film thickness, ΔH(t), is characterized by a minimum of ΔH ≈ 60 Oe present in the region of thicknesses of 30 to 60 nm. The behavior of dependence ΔH(t) is determined by ratio σ(t)/t at small thicknesses t ≤ 5 nm and by the behavior of σ(t) at t ≥ 5 nm. 相似文献
7.
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
8.
S. Yu. Turishchev V. A. Terekhov D. A. Koyuda A. V. Ershov A. I. Mashin E. V. Parinova D. N. Nesterov D. A. Grachev I. A. Karabanova E. P. Domashevskaya 《Semiconductors》2017,51(3):349-352
The problem of the efficiency of the controllable formation of arrays of silicon nanoparticles is studied on the basis of detailed investigations of the electronic structure of multilayer nanoperiodic a-SiO x /SiO2, a-SiO x /Аl2О3, and a-SiO x /ZrO2 compounds. Using synchrotron radiation and the X-ray absorption near edge structure (XANES) spectroscopy technique, a modification is revealed for the investigated structures under the effect of high-temperature annealing at the highest temperature of 1100°C; this modification is attributed to the formation of silicon nanocrystals in the layers of photoluminescent multilayer structures. 相似文献
9.
I. L. Drichko A. M. D’yakonov I. Yu. Smirnov Yu. M. Gal’perin V. V. Preobrazhenskii A. I. Toropov 《Semiconductors》2004,38(6):702-711
The complex high-frequency conductivity of GaAs/Al0.3Ga0.7As heterostructures that are δ-doped and modulation-doped with silicon was investigated by acoustic methods under conditions of the integer quantum Hall effect. Both the real (σ1) and imaginary (σ2) parts of the complex conductivity σ(ω, H)=σi?iσ2 were determined from the dependences of the absorption and velocity of surface acoustic waves on magnetic field. It is shown that, in the heterostructures with electron density ns=(1.3–7)×1011 cm?2 and mobility μ=(1–2)×105 cm2/(V s), the high-frequency conductivity near the centers of the Hall plateau is due to electron hopping between localized states. It is established that, with filling numbers 2 and 4, the conductivity of the Al0.3Ga0.7As:Si layer efficiently shunts the high-frequency hopping conductivity of the two-dimensional interface layer. A method of separating the contributions of the interface and Al0.3Ga0.7As:Si layers to the hopping conductivity σ(ω, H) is developed. The localization length of electrons in the interface layer is determined on the basis of the nearest neighbor hopping model. It is shown that, near the centers of the Hall plateau, both σ(ω, H) and ns depend on the cooling rate of a GaAs/Al0.3Ga0.7As sample. As a result, the sample “remembers” the cooling conditions. Infrared light and static strain also change both σ(ω, H) and ns. We attribute this behavior to the presence of two-electron defects (so-called DX? centers) in the Al0.3Ga0.7As:Si layer. 相似文献
10.
Capture centers (traps) are studied in silicon-on-insulator (SOI) structures obtained by bonding and hydrogen-induced stratification. These centers are located at the Si/SiO2 interface and in the bulk of the split-off Si layer. The parameters of the centers were determined using charge deep-level transient spectroscopy (Q-DLTS) with scanning over the rate window at fixed temperatures. Such a method allows one to study the traps near the Si midgap at temperatures near 295 K. It is shown that the density of traps with a continuous energy spectrum, which are located at the bonded Si/SiO2 interface, decreases by more than four orders of magnitude at the mid-gap compared with the peak density observed at the activation energy E a ≈0.2–0.3 eV. The capture centers are also found in the split-off Si layer of the fabricated SOI structures. Their activation energy at room temperature is E a =0.53 eV, the capture cross section is 10?19 cm2, and the concentration is (0.7–1.7)×1013 cm?3. It is assumed that these capture centers are related to deep bulk levels induced by electrically active impurities (defects) in the split-off Si layer close to the Si/SiO2 interface. 相似文献
11.
A. A. Kudryashov V. G. Kytin R. A. Lunin V. A. Kulbachinskii A. Banerjee 《Semiconductors》2016,50(7):869-875
The Shubnikov–de Haas effect and the Hall effect in n-Bi2–xTlxSe3 (x = 0, 0.01, 0.02, 0.04) and p-Sb2–xTlxTe3 (x = 0, 0.005, 0.015, 0.05) single crystals are studied. The carrier mobilities and their changes upon Tl doping are calculated by the Fourier spectra of oscillations. It is found shown that Tl doping decreases the electron concentration in n-Bi2–xTlxSe3 and increases the electron mobility. In p-Sb2–xTlxTe3, both the hole concentration and mobility decrease upon Tl doping. The change in the crystal defect concentration, which leads to these effects, is discussed. 相似文献
12.
Nd/Nb-co-substituted Bi3.15Nd0.85Ti3?x Nb x O12 (BNTN x , x = 0.01, 0.03, 0.05 and 0.07) thin films were grown on Pt/Ti/SiO2/Si (100) substrates by chemical solution deposition. The effects of Nb content on the micro-structural, dielectric, ferroelectric, leakage current and capacitive properties of the BNTN x thin films were investigated. A low-concentration substitution with Nb ions in BNTN x can greatly enhance its remanent polarization (2P r) and reduce the coercive field (2E c) compared with those of Bi4Ti3O12 (BIT) thin film. The highest 2P r (71.4 μC/cm2) was observed in the BNTN0.03 thin film when the 2E c was 202 kV/cm. Leakage currents of all the films were on the order of 10?6 to 10?5 A/cm2, and the BNTN0.03 thin film has a minimum leakage current (2.1 × 10?6 A/cm2) under the high electric field (267 kV/cm). Besides, the C–V curve of the BNTN0.03 thin film is the most symmetrical, and the maximum tunability (21.0%) was also observed in this film. The BNTN0.03 thin film shows the largest dielectric constant and the lowest dielectric loss and its maximum Curie temperature is 410 ± 5°C. 相似文献
13.
Avula Edukondalu T. Sripathi Shaik Kareem Ahmmad Syed Rahman K. Sivakumar 《Journal of Electronic Materials》2017,46(2):808-816
Glass with compositions xK2O-(30 ? x)Li2O-10WO3-60B2O3 for 0 ≤ x ≤ 30 mol.% have been prepared using the normal melt quenching technique. The optical reflection and absorption spectra were recorded at room temperature in the wavelength range 300–800 nm. From the absorption edge studies, the values of the optical band gap (E opt) and Urbach energy (ΔE) have been evaluated. The values of E opt and ΔE vary non-linearly with composition parameter, showing the mixed alkali effect. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple Di-Domenico model. 相似文献
14.
Tianxiang Yan Shaokai Ren Xing Ma Feifei Han Liang Fang Biaolin Peng Laijun Liu Xiaojun Kuang Brahim Elouadi 《Journal of Electronic Materials》2018,47(12):7106-7113
(1???x)K0.5Na0.5NbO3-x(Bi0.5K0.5)ZrO3 [abbreviated as (1???x)KNN-xBKZ, 0?≤?x?≤?0.08] lead-free ceramics have been fabricated by a solid-state processing route. Based on the x-ray diffraction data and temperature-dependent dielectric characteristics, an orthorhombic phase for x?≤?0.03 and single rhombohedral one for x?≥?0.05 at room temperature were determined. The cell volume firstly increases, then decreases and finally increases with increasing BKZ, depending on ionic size and crystallographic structure. For the sample of x?=?0.05, a temperature-stable high permittivity (~?1736?±?15%) along with low dielectric loss tangent (≤?5%) is recorded from 158°C to 407°C. In addition, the activation energies of dielectric relaxation and dc conductivity at high temperatures were characterized by impedance spectroscopy. A combined effect of lattice distortion and oxygen vacancies on the magnitude of activation energies was discussed. 相似文献
15.
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
16.
E. V. Michailovska I. Z. Indutnyi P. E. Shepeliavyi N. V. Sopinskii 《Semiconductors》2016,50(1):97-102
The effect of photoluminescence polarization memory in nc-Si–SiO x light-emitting structures containing Si nanoparticles (nc-Si) in an oxide matrix is for the first time studied. The polarization properties of continuous and porous nanostructures passivated in HF vapors (or solutions) are studied. It is established that the polarization memory effect is manifested only after treatment of the structures in HF. The effect is also accompanied by a shift of the photoluminescence peak to shorter wavelengths and by a substantial increase in the photoluminescence intensity. It is found that, in anisotropic nc-Si–SiO x samples produced by oblique deposition in vacuum, the degree of linear photoluminescence polarization in the sample plane exhibits a noticeable orientation dependence and correlates with the orientation of SiO x nanocolumns forming the structure of the porous layer. These effects are attributed to the transformation of symmetrically shaped Si nanoparticles into asymmetric elongated nc-Si particles upon etching in HF. In continuous layers, nc-Si particles are oriented randomly, whereas in porous structures, their preferential orientation coincides with the orientation of oxide nanocolumns. 相似文献
17.
The effect of the oxygen content (\(C_{O_2 } \)) in the gas mixture (20% of SiH4 + 80% of Ar) + O2 and the surface area of an erbium target (SEr) on the composition and Er3+ photoluminescence of amorphous a-SiOx:(H, Er, O) films prepared by dc magnetron sputtering has been investigated. Analysis of the experimental data shows that [Er-O] and [Er-O-Si-O] clusters are formed in the gas plasma due to the competing processes of oxidation and sputtering of Si and Er targets and to the interaction of [Si-O] and [Er-O] clusters with each other and with the oxygen in the gas phase. The discontinuities in the dependences of the contents of erbium-bound oxygen and erbium in a film, and N O Er-O and NEr = f(\(C_{O_2 } \), SEr), at \(C_{O_2 } \) ≈ (5–6.5) mol % supports the hypothesis on the existence of different erbium clusters. The necessary conditions for preparing a-SiOx:(H, Er, O) films with the highest photoluminescence intensity of erbium ions at a wavelength of 1.54 μm are determined. 相似文献
18.
P. P. Konstantinov L. V. Prokof’eva M. I. Fedorov D. A. Pshenai-Severin Yu. I. Ravich V. V. Kompaniets V. A. Chistyakov 《Semiconductors》2005,39(9):1023-1027
The Hall factor and thermoelectric properties of an n-Bi2Te2.7Se0.3 solid solution with the roomtemperature Seebeck coefficient |S| = 212 μV/K have been studied in the temperature range 77–350 K. The observed temperature dependences demonstrate a number of specific features, which were earlier found in samples with a lower electron density N. The effect of these specific features on the thermoelectric figure of merit Z appears to be more favorable for the sample under study: this sample is most efficient in the temperature range 120–340 K, and the average value of ZT is 0.71. It is found that a rise in the density N enhances the factor responsible for the effective mass decreasing as the temperature increases. This effect appears when the analysis is carried out in terms of a single-band parabolic model with N = const(T). This finding suggests that the most probable reason for the unusual behavior of these properties is the complex structure of the electron spectrum. Temperature dependences obtained from calculations of the transport coefficients show good agreement with the experimental data for two samples of the mentioned composition with different electron densities. The calculations have been performed in terms of a two-band model and an acoustic scattering mechanism and take into account the anisotropy and nonparabolicity of the light-electron spectrum. 相似文献
19.
I. E. Tyschenko A. B. Talochkin A. G. Cherkov K. S. Zhuravlev A. Misiuk M. Voelskow W. Skorupa 《Semiconductors》2003,37(4):462-467
The influence of hydrostatic compression on the implantation-induced synthesis of Ge nanocrystals in SiO2 host was studied. It is found that high-temperature annealing under pressure leads to retardation of Ge diffusion in SiO2. It is shown that unstressed Ge nanocrystals are formed as a result of conventional annealing (under atmospheric pressure). Annealing under pressure is accompanied by formation of hydrostatically stressed Ge nanocrystals. The stress in Ge nanocrystals was determined from optical-phonon frequencies in the Raman spectra. The shift of Raman resonance energy (E1, E1 + Δ1) corresponds to the quantization of the ground-state energy for a two-dimensional exciton at the critical point M1 of germanium. It is ascertained that a photoluminescence band peaked at 520 nm is observed only in the spectra of the films which contain stressed Ge nanocrystals. 相似文献
20.
V. Ya. Bratus S. M. Okulov É. B. Kaganovich I. M. Kizyak É. G. Manoilov 《Semiconductors》2004,38(5):598-602
Nanocrystalline silicon films formed using laser ablation of silicon targets were studied using electron spin resonance. The measurements were performed in the X band with modulation of the magnetic field at a frequency of ~100 kHz at temperatures of 300 and 77 K. Two types of spectra were observed. The first type of spectra is related to the high concentration of dangling silicon bonds in Si nanocrystals and SiOx sheaths of nanocrystals and are inherent in nanocrystalline silicon (nc-Si) films that do not exhibit photoluminescence in the visible region of the spectrum. The second type of spectra is related to the presence of E′ centers, nonbridging oxygen hole centers (NBOHC), and peroxide radicals and is characteristic of films with photoluminescence in the visible region of the spectrum, which indicates that high-barrier SiO2 layers exist in these films. An increase in the photoluminescence intensity and a decrease in the signal of electron spin resonance were observed in porous nc-Si films exposed to atmospheric air for a long time. 相似文献