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1.
We have investigated the structural and electrical characteristics of the Ag/n-TiO2/p-Si/Al heterostructure. Thin films of pure TiO2 were deposited on p-type silicon (100) by optimized pulsed laser ablation with a KrF-excimer laser in an oxygen-controlled environment. X-ray diffraction analysis showed the formation of crystalline TiO2 film having a tetragonal texture with a strong (210) plane as the preferred direction. High purity aluminium and silver metals were deposited to obtain ohmic contacts on p-Si and n-TiO2, respectively. The current–voltage (I–V) characteristics of the fabricated heterostructure were studied by using thermionic emission diffusion mechanism over the temperature range of 80–300 K. Parameters such as barrier height and ideality factor were derived from the measured I–V data of the heterostructure. The detailed analysis of I–V measurements revealed good rectifying behavior in the inhomogeneous Ag/n-TiO2/p-Si(100)/Al heterostructure. The variations of barrier height and ideality factor with temperature and the non-linearity of the activation energy plot confirmed that barrier heights at the interface follow Gaussian distributions. The value of Richardson’s constant was found to be 6.73 × 105 Am?2 K?2, which is of the order of the theoretical value 3.2 × 105 Am?2 K?2. The capacitance–voltage (C–V) measurements of the heterostructure were investigated as a function of temperature. The frequency dependence (Mott–Schottky plot) of the C–V characteristics was also studied. These measurements indicate the occurrence of a built-in barrier and impurity concentration in TiO2 film. The optical studies were also performed using a UV–Vis spectrophotometer. The optical band gap energy of TiO2 films was found to be 3.60 eV. 相似文献
2.
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
3.
Thermal-activation and photoactivation methods were used to ascertain the existence of two-hole traps in p-ZnTe crystals and two-electron traps in n-ZnS. It was found that these traps have a large number of energy states that are grouped in two series of levels: EV+(0.46–0.66) eV and EV+(0.06–0.26) eV in p-ZnTe and EC?(0.6–0.65) eV and EC?(0.14–0.18) eV in n-ZnS. Both the hole and the electron traps belong to the class of slow traps with bikinetic properties. These traps feature normal kinetic properties in the state with a single trapped charge carrier and feature anomalous kinetic properties in the state with two charge carriers. Multiple-parameter models allowing for a relation of traps in p-ZnTe and n-ZnS to the vacancy-impurity pairs distributed according to their interatomic distances and localized in the region of microinhomogeneities with collective electric fields that repel the majority charge carriers are suggested. The main special features of behavior of electron and hole traps are explained consistently using the above models. 相似文献
4.
A. A. Gutkin M. É. Rudinsky P. N. Brunkov A. A. Klochikhin V. Yu. Davydov H. -Y. Chen S. Gwo 《Semiconductors》2008,42(12):1416-1419
Dependences of differential capacitance of the electrolyte-n-InN (0001) contact on the bias voltage are studied. Their analysis of the basis of a model similar to a model of the MIS structure shows that the energy spectrum of surface states of InN above the conduction band bottom can be represented by two, relatively narrow, bands of deep levels described by the Gaussian distribution. Parameters of these bands are as follows: the average energy counted from the conduction band bottom, ΔE 1 ≈ 0.15 eV and ΔE 2 ≈ 0.9 eV; and the mean-square deviation, ΔE 1 ≈ 0.15–0.25 eV and ΔE 2 ≈ 0.05–0.1 eV. The total density of states in the bands are (1–2.5) × 1012 and (0.2–4) × 1012 cm–2. 相似文献
5.
O. Yu. Ledyaev A. M. Strel’chuk A. N. Kuznetsov N. V. Seredova A. S. Zubrilov A. A. Volkova A. E. Nikolaev A. A. Lebedev 《Semiconductors》2005,39(12):1403-1405
Epitaxial GaN layers were grown by hydride vapor phase epitaxy (HVPE) on commercial (CREE Inc., USA) p+-6H-SiC substrates (Na ? Nd ≈ 7.8 × 1017 cms?3) and n+-6H-SiC Lely substrates with a predeposited p+-6H-SiC layer. A study of the electrical properties of the n-GaN/p-SiC heterostructures obtained confirmed their fairly good quality and demonstrated that the given combination of growth techniques is promising for fabrication of bipolar and FET transistors based on the n-GaN/p-SiC heterojunctions. 相似文献
6.
T. A. Pagava 《Semiconductors》2004,38(6):639-643
p-Si samples irradiated with 8-Mev electrons are studied. It is suggested that the multicomponent V3+O or V2+O2 complexes are not recombination centers on the basis of an analysis of the dependences of the minority-carrier lifetime τ, the resistivity ρ, the concentration p, and the Hall mobility μH on the temperature of isochronous annealing Tann. Deep donors with energy levels at ΔEi=Ev+0.40 eV and the V3+O3 and the V3+O2 complexes affect the values of μH and τ. The curves of isochronous annealing are used to determine the annealing-activation energies Eann for defects such as K centers, interstitial carbon atoms Ci, the V+B and V2+O2 complexes, divacancies V2, and defects with a level at ΔEi=Ev+0.20 eV. These energies were found to be equal to Eann=0.9, 0.25, 1.6, 2, 1.54, and 2.33 eV, respectively. 相似文献
7.
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
8.
I. O. Maiboroda J. V. Grishchenko I. S. Ezubchenko I. S. Sokolov I. A. Chernych A. A. Andreev M. L. Zanaveskin 《Semiconductors》2018,52(6):776-782
The nonlinear behavior of the I–V characteristics of symmetric contacts between a metal and degenerate n-GaN, which form oppositely connected Schottky diodes, is investigated at free-carrier densities from 1.5 × 1019 to 2.0 × 1020 cm–3 in GaN. It is demonstrated that, at an electron density of 2.0 × 1020 cm–3, the conductivity between metal (chromium) and GaN is implemented via electron tunneling and the resistivity of the Cr–GaN contact is 0.05 Ω mm. A method for determining the parameters of potential barriers from the I–V characteristics of symmetric opposite contacts is developed. The effect of pronounced nonuniformity of the current density and voltage distributions over the contact area at low contact resistivity is taken into account. The potential-barrier height for Cr–n+-GaN contacts is found to be 0.47 ± 0.04 eV. 相似文献
9.
For an NMOS structure with 3.7-nm-thick oxide, dynamic I-V characteristics are digitally measured by applying an upward and a downward gate-voltage ramp. An averaging procedure is employed to deduce the tunneling (active) current component and the quasi-static C-V characteristic (CVC). Analyzing the depletion segment of the CVC provides reliable values of the semiconductor doping level, the oxide capacitance and thickness, and the sign and density of oxide-fixed charge, as well as estimates of the dopant concentration in the poly-Si region. These data are used to identify the Ψs(V g), V i(V g), and I t(V i) characteristics, where Ψs is the n-Si surface potential, V i is the voltage drop across the oxide, V g is the gate voltage, and I t is the tunneling current; the gate-voltage range explored extends to prebreakdown fields (~13 MV cm?1). The results are obtained without recourse to fitting parameters and without making any assumptions as to the energy spectrum of electrons tunneling from the n-Si deep-accumulation region through the oxide. It is believed that experimental I t-V i and Ψs-V g characteristics will provide a basis for developing a theory of tunneling covering not only the degeneracy and size quantization of the electron gas in the semiconductor but also the nonclassical profile of the potential barrier to electron tunneling associated with the oxide-fixed charge. 相似文献
10.
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
11.
Reactions of annealing of A centers (VO) and complex centers consisting of interstitial carbon atoms and substitutional carbon atoms (CiCs) in n-Si irradiated with fast electrons or 60Co gamma quanta were analyzed. The kinetics of isochronous annealing of the above centers was evaluated. By comparing the results of calculations with published experimental data, which were obtained by measuring the concentration of centers with the level Ec?0.17 eV in the course of isochronous heat treatment of irradiated n-Si, the dissociation energy E for the CiCs complex was estimated at 1.10±0.05 eV. The activation energy for annealing of this center was found to be equal to \(E_{aC_i C_s } \approx 2.0eV\). The dissociation energy for the A center was estimated at EA=1.94 eV. 相似文献
12.
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
13.
Toshiyuki Takizawa Satoshi Nakazawa Tetsuzo Ueda 《Journal of Electronic Materials》2008,37(5):628-634
Surface passivation by SiN x films is indispensable for high-power operation of AlGaN/GaN heterojunction field-effect transistors (HFETs) since it can effectively suppress collapse in the drain current. So far, the plasma-enhanced chemical vapor deposition technique has been used for the SiN x deposition; however, possible damage induced by the plasma processing may affect direct-current performance or reliability. In this paper, we present subsequent deposition of SiN x ultrathin films on AlGaN/GaN in the same metalorganic chemical vapor deposition reactor. It is experimentally found that this in situ SiN x passivation doubles the sheet carrier density at the AlGaN/GaN interface from that of the unpassivated sample. High-resolution cross-sectional transmission electron microscopy reveals that in situ SiN x is crystallized on the AlGaN layer as island-like structures via the Stranski-Krastanov growth mode. The lattice constants of in situ SiN x are estimated to be a ≈ 3.2 Å and c ≈ 2.4 Å, which are quite different from those of well-known Si3N4 crystal structures. First-principles calculation predicts that the crystal structure of in situ SiN x is the defect wurtzite structure, which well explains the experimental results. The passivation technique using crystalline SiN x films would be promising for high-power and high-frequency applications of AlGaN/GaN HFETs. 相似文献
14.
T. A. Pagava 《Semiconductors》2007,41(6):631-633
p-Si single crystals grown by the Czochralski method were studied; the hole concentration in these crystals was p = 6 × 1013 cm?3. The samples were irradiated with 8-MeV electrons at 300 K and were then annealed isochronously in the temperature range T ann = 100–500°C. The studies were carried out using the Hall method in the temperature range of 77–300 K. It is shown that annealing of divacancies occurs via their transformation into the B s V 2 complexes. This complex introduces the energy level located at E v + 0.22 eV into the band gap and is annealed out in the temperature range of 360–440°C. It is assumed that defects with the level E v + 0.2 eV that anneal out in the temperature range T ann = 340–450°C are multicomponent complexes and contain the atoms of the doping and background impurities. 相似文献
15.
O. A. Ageev A. E. Belyaev N. S. Boltovets V. N. Ivanov R. V. Konakova Ya. Ya. Kudryk P. M. Lytvyn V. V. Milenin A. V. Sachenko 《Semiconductors》2009,43(7):865-871
Mechanism of charge transport in a diode of a silicon carbide’s Schottky barrier formed by a quasi-amorphous interstitial phase TiB x on the surface of n-6H-SiC (0001) single crystals with an uncompensated donor (nitrogen) concentration of ~1018 cm?3 and dislocation density of ~(106–108) cm?2 has been studied. It is demonstrated that, at temperatures T ? 400 K, the charge transport is governed by the tunneling current along dislocations intersecting the space charge region. At T > 400 K, the mechanism of charge transport changes to a thermionic mechanism with a barrier height of ~0.64 eV and ideality factor close to 1.3. 相似文献
16.
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
17.
B. A. Komarov 《Semiconductors》2004,38(9):1041-1046
Deep-level transient spectroscopy is used to study the formation of complexes that consist of a radiation defect and a residual impurity atom in silicon. It is established that heat treatment of the diffused Si p+-n junctions irradiated with fast electrons lead to the activation of a residual Fe impurity and the formation of the FeVO (E0.36 trap) and FeV2 (H0.18 trap) complexes. The formation of these traps is accompanied by the early (100–175°C) stage of annealing of the main vacancy-related radiation defects: the A centers (VO) and divacancies (V2). The observed complexes are electrically active and introduce new electron (E0.36: E t e =E c -0.365 eV, σ n =6.8×10?15 cm2) and hole (H0.18: E t h =E v +0.184 eV, σ p =3.0×10?15 cm2) levels into the silicon band gap and have a high thermal stability. It is believed that the complex FeVO corresponds to the previously observed and unidentified defects that have an ionization energy of E t e =E c ?(0.34–0.37) eV and appear as a result of heat treatment of irradiated diffused Si p+-n junctions. 相似文献
18.
I. V. Grekhov P. A. Ivanov N. D. Il’inskaya O. I. Kon’kov A. S. Potapov T. P. Samsonova 《Semiconductors》2008,42(2):211-214
High-voltage (900 V) 4H-SiC Schottky diodes terminated with a guard p-n junction were fabricated and studied. The guard p-n junction was formed by room-temperature boron implantation with subsequent high-temperature annealing. Due to transient enhanced boron diffusion during annealing, the depth of the guard p-n junction was equal to about 1.7 μm, which is larger by approximately 1 μm than the projected range of 11 B ions in 4H-SiC. The maximum reverse voltage of fabricated 4H-SiC Schottky diodes is found to be limited by avalanche breakdown of the planar p-n junction; the value of the breakdown voltage (910 V) is close to theoretical estimate in the case of the impurity concentration N = 2.5 × 1015 cm?3 in the n-type layer, thickness of the n-type layer d = 12.5 μm, and depth of the p-n junction r j = 1.7 μm. The on-state diode resistance (3.7 mΩ cm2) is controlled by the resistance of the epitaxial n-type layer. The recovery charge of about 1.3 nC is equal to the charge of majority charge carriers that are swept out of an epitaxial n-type layer under the effect of a reverse voltage. 相似文献
19.
M. V. Virko V. S. Kogotkov A. A. Leonidov V. V. Voronenkov Yu. T. Rebane A. S. Zubrilov R. I. Gorbunov P. E. Latyshev N. I. Bochkareva Yu. S. Lelikov D. V. Tarhin A. N. Smirnov V. Yu. Davydov Yu. G. Shreter 《Semiconductors》2016,50(5):699-704
The physical and technological basics of the method used to lift off lightly and moderately doped n-GaN films from heavily doped n+-GaN substrates are considered. The detachment method is based on the free-charge-carrier absorption of IR laser light, which is substantially higher in n+-GaN films. 相似文献
20.
O. Rocha-Rocha M. Cortez-Valadez A. R. Hernández-Martínez R. Gámez-Corrales Ramón A. B. Alvarez R. Britto-Hurtado Y. Delgado-Beleño C. E. Martinez-Nuñez A. Pérez-Rodríguez H. Arizpe-Chávez M. Flores-Acosta 《Journal of Electronic Materials》2017,46(2):802-807
Bimetallic Ag/Cu nanoparticles have been obtained by green synthesis using Opuntia ficus-indica plant extract. Two synthesis methods were applied to obtain nanoparticles with core–shell and Janus morphologies by reversing the order of precursors. Transmission electronic microscopy revealed size of 10 nm and 20 nm for the core–shell and Janus nanoparticles, respectively. Other small particles with size of up to 2 nm were also observed. Absorption bands attributed to surface plasmon resonance were detected at 440 nm and 500 nm for the core–shell and Janus nanoparticles, respectively. Density functional theory predicted a breathing mode type (BMT) located at low wavenumber due to small, low-energy clusters of (AgCu) n with n = 2 to 9, showing a certain correlation with the experimental one (at 220 cm?1). The dependence of the BMT on the number of atoms constituting the cluster is also studied. 相似文献