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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.
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
3.
Yunus Ozen Tunc Sertel Saime Sebnem Cetin Suleyman Ozcelik 《Journal of Electronic Materials》2018,47(12):7129-7133
The structural, optical, electrical and electrical–optical properties of a double-junction GaAsP light-emitting diode (LED) structure grown on a GaP (100) substrate by using a molecular beam epitaxy technique were investigated. The p–n junction layers of GaAs1?xPx and GaAs1?yPy, which form the double-junction LED structure, were grown with two different P/As ratios. High-resolution x-ray diffraction (HRXRD), photoluminescence (PL), and current–voltage (I–V) measurements were used to investigate the structural, optical and electrical properties of the sample. Alloy composition values (x, y) and some crystal structure parameters were determined using HRXRD measurements. The phosphorus compositions of the first and second junctions were found to be 63.120% and 82.040%, respectively. Using PL emission peak positions at room temperature, the band gap energies (Eg) of the first and second junctions were found to be 1.867 eV and 2.098 eV, respectively. In addition, the alloy compositions were calculated by Vegard’s law using PL measurements. The turn-on voltage (Von) and series resistance (Rs) of the device were obtained from the I–V measurements to be 4.548 V and 119 Ω, respectively. It was observed that the LED device emitted in the red (664.020 nm) and yellow (591.325 nm) color regions. 相似文献
4.
F. Erdem Arkun Dennis D. Edwall Jon Ellsworth Sheri Douglas Majid Zandian Michael Carmody 《Journal of Electronic Materials》2017,46(9):5374-5378
Recent advances in growth of Hg1?x Cd x Te films on large-area (7 cm × 7.5 cm) CdZnTe (CZT) substrates is presented. Growth of Hg1?x Cd x Te with good uniformity on large-area wafers is achieved using a Riber 412 molecular beam epitaxy (MBE) tool designed for growth of Hg1?x Cd x Te compounds. The reactor is equipped with conventional CdTe, Te, and Hg sources for achieving uniform exposure of the wafer during growth. The composition of the Hg1?x Cd x Te compound is controlled in situ by employing a closed-loop spectral ellipsometry technique to achieve a cutoff wavelength (λ co) of 14 μm at 78 K. We present data on the thickness and composition uniformity of films grown for large-format focal-plane array applications. The composition and thickness nonuniformity are determined to be <1% over the area of a 7 cm × 7.5 cm wafer. The films are further characterized by Fourier-transform infrared spectroscopy, optical microscopy, and Hall measurements. Additionally, defect maps show the spatial distribution of defects generated during the epitaxial growth of the Hg1?x Cd x Te films. Microdefect densities are in the low 103 cm?2 range, and void defects are below 500 cm?2. Dislocation densities less than 5 × 105 cm?2 are routinely achieved for Hg1?x Cd x Te films grown on CZT substrates. HgCdTe 4k × 4k focal-plane arrays with 15 μm pitch for astronomical wide-area infrared imagers have been produced using the recently developed MBE growth process at Teledyne Imaging Sensors. 相似文献
5.
A. E. Belyaev N. S. Boltovets V. N. Ivanov L. M. Kapitanchuk R. F. Konakova Ya. Ya. Kudryk V. V. Milenin 《Semiconductors》2009,43(6):726-729
The radiation and thermal stability of the Schottky-barrier structures deposited by the magnetron sputtering of zirconium diboride onto the (0001) face of the Lely-grown n-6H(15R)SiC single crystals with the uncompensated-donor concentration of ~1018 cm?3 was investigated by the methods of the I–V and C–V characteristics combined with the layer-by-layer Auger analysis. It is shown that the use of quasi-amorphous ZrB2 films when manufacturing contacts on n-6H(15R)SiC leads to no changes in the Schottky-barrier characteristics during rapid thermal annealing to 800°C in the range of 60Co γ-ray irradiation doses of 103–107 Gy. 相似文献
6.
P. Martyniuk P. Madejczyk W. Gawron J. Rutkowski 《Journal of Electronic Materials》2018,47(10):5752-5758
In this paper, the performance of sequential dual-band mid-wavelength N+-n-p-p-P+-p-p-n-n+ back-to-back HgCdTe photodiode grown by metal-organic chemical vapor deposition (MOCVD) operating at room temperature is presented. The details of the MOCVD growth procedure are given. The influence of p-type separating-barrier layer on dark current, photocurrent and response time was analyzed. Detectivity without immersion D* higher than 1 × 108 cmHz1/2/W was estimated for λPeak = 3.2 μm and 4.2 μm, respectively. A response time of τs ~ 1 ns could be reached in both MW1 and MW2 ranges for the optimal P+ barrier Cd composition at the range 0.38–0.42, and extra series resistance related to the processing RSeries equal to 500 Ω. 相似文献
7.
P. V. Biryulin S. A. Dudko S. A. Konovalov Yu. A. Pelevin V. I. Turinov 《Semiconductors》2003,37(12):1383-1386
The ZnS-CdxHg1?xTe interface was investigated using the capacitance-voltage characteristics of MIS structures in experimental samples. During fabrication of the n+-p junctions based on p-CdxHg1?xTe, the density of states within the range N ss =(1–6)×1011 cm?2 eV?1 at T=78 K was obtained. The experiments showed that the conditions in which n+-p junctions are fabricated only slightly affect the state of the ZnS-CdHgTe interface. The negative voltages of the at bands V FB , even if immediately after deposition of the ZnS films V FB >0, point to the enrichment of the ZnS-p-CdHgTe near-surface layer with majority carriers, specifically, holes. This led to a decrease in the leakage current over the surface. During long-term storage (as long as ~15 years) in air at room temperature, no degradation of differential resistance R d , current sensitivity S i , and detectivity D* of such n+-p junctions with a ZnS protection film was observed. 相似文献
8.
F. C. Peiris M. V. Lewis G. Brill Kevin Doyle T. H. Myers 《Journal of Electronic Materials》2018,47(10):5715-5718
Using spectroscopic ellipsometry, the temperature-dependence of the dielectric functions of a series of Hg1?xCdxSe thin films deposited on both ZnTe/Si(112) and GaSb(112) substrates were investigated. Initially, for each sample, room-temperature ellipsometric spectra were obtained from 35 meV to 6 eV using two different ellipsometers. Subsequently, ellipsometry spectra were obtained from 10 K to 300 K by incorporating a cryostat to the ellipsometer. Using a standard inversion technique, the spectroscopic ellipsometric data were modeled in order to obtain the temperature-dependent dielectric functions of each of the Hg1?xCdxSe thin films. The results indicate that the E1 critical point blue-shifts as a function of Cd-alloy concentration. The temperature-dependence of E1 was fitted to a Bose–Einstein occupation distribution function, which consequently allowed us to determine the electron–phonon coupling of Hg1?xCdxSe alloys. From the fitting results, we obtain a value of 17 ± 2 meV for the strength of the electron–phonon coupling for Hg1?xCdxSe alloy system, which compares nominally with the binary systems, such as CdSe and CdTe, which have values around 38 meV and 16 meV, respectively. This implies that the addition of Hg into the CdSe binary system does not significantly alter its electron–phonon coupling strength. Raman spectroscopy measurements performed on all the samples show the HgSe-like transverse optic (TO) and longitudinal optic (LO) phonons (~?130 cm?1 and?~?160 cm?1, respectively) for all the samples. While there is a slight red-shift of the HgSe-like TO peak as a function of the Cd-concentration, HgSe-like LO peak does not significantly change with the alloy concentration. 相似文献
9.
Min-Suk Oh 《Journal of Electronic Materials》2018,47(4):2257-2262
We investigated the effect of KrF excimer laser surface treatment on Pt/Ti ohmic contacts to Ga-doped n-ZnO (Nd = 4.3 × 1017 cm?3). The treatment of the n-ZnO surfaces by laser irradiation greatly improved the electrical characteristics of the metal contacts. The Pt/Ti ohmic layer on the laser-irradiated n-ZnO showed specific contact resistances of 2.5 × 10?4 ~ 4.8 × 10?4 Ω cm2 depending on the laser energy density and gas ambient, which were about two orders of magnitude lower than that of the as-grown sample, 8.4 × 10?2 Ω cm2. X-ray photoelectron spectroscopy and photoluminescence measurements showed that the KrF excimer laser treatments increased the electron concentration near the surface region of the Ga-doped n-ZnO due to the preferential evaporation of oxygen atoms from the ZnO surface by the laser-induced dissociation of Zn-O bonds. 相似文献
10.
Tasuku Sakuma Shunsuke Nishino Masanobu Miyata Mikio Koyano 《Journal of Electronic Materials》2018,47(6):3177-3183
Transition-metal trichalcogenides MX3 (M = Ti, Zr, Nb, Ta; X = S, Se) are well-known inorganic quasi-one-dimensional conductors. Among them, we have investigated the thermoelectric properties of titanium trisulfide TiS3 microribbon. The electrical resistivity ρ, thermal conductivity κ, and thermoelectric power S were measured using 3ω method. The weight mean values were found to be ρ = 5 mω m and κ = 10 W K?1 m?1 along the one-dimensional direction (b-axis) of the TiS3 microribbon. Combined with the thermoelectric power S = ?530 μV K?1, the figure of merit was calculated as ZT = 0.0023. This efficiency is the same as that of randomly oriented bulk TiS3. We also estimated the anisotropy of σ and κ using the present results and those for randomly oriented bulk material. The obtained weak anisotropy for TiS3 is attributable to strong coupling between triangular columns consisting of TiS3 units. These experimental results are consistent with theoretical results obtained using density functional theory (DFT) calculations. 相似文献
11.
Ya-Peng Li Ying-Feng Li Jian-Yuan Wang Yong-Hong Zhang Feng Xu 《Journal of Electronic Materials》2017,46(11):6341-6346
The electrical properties and band offset of ZnS/n-Si(111) heterojunctions with and without annealing were analyzed. The result showed that the rectifying characteristics of ZnS/n-Si(111) heterojunctions became better and the leakage current increased after annealing. This phenomenon is mostly due to the volatilization of S atoms of ZnS films and leads to defect levels appearing at the interface of the ZnS/n-Si(111) hetrojunctions. The valence band offset (ΔE V) of the ZnS/n-Si(111) heterojunctions can be calculated to be ?0.7 ± 0.15 eV by means of photoelectron spectroscopy, indicating that the band offsets of ZnS/n-Si(111) heterojunctions show a type-II band alignment. 相似文献
12.
Y. Javed M. A. Rafiq M. M. Hasan Sikander M. Mirza 《Journal of Electronic Materials》2018,47(11):6443-6449
Ab-initio calculations using the full potential linearized augmented plane-wave technique and the semi-classical Boltzmann theory are used to study thermoelectric properties of unstrained SnS and at 1%, 2% and 3% applied biaxial tensile (BT) strain. The studies are carried out at 800 K for p-type and n-type carriers. For an increase in BT strain, lattice constants of SnS change causing changes in the band structure and increase in the band gap which in turn modifies thermoelectric coefficients. In the case of unstrained SnS, the maximum thermopower (S) obtained is 426 μV/K at carrier concentration 5.40?×?1018 cm?3 for p-type carriers and 435 μV/K at carrier concentration 1.68?×?1018 cm?3 for n-type carriers. At 3% applied BT strain, S is increased to 696 μV/K at carrier concentration 4.61?×?1017 cm?3 for p-type carriers and 624 μV/K at carrier concentration 3.21?×?1017 cm?3 for n-type carriers. The power factor (PF) increases?~?2 times at 3% BT strain as compared to unstrained SnS, and it is 6.20 mW K?2 m?1 for p-type carriers. For n-type carriers, PF at 3% applied BT is slightly less than the PF for unstrained SnS, which is 6.81 mW K?2 m?1. For both types of carriers, the figure of merit (ZT) is found to be?~?1.5 for unstrained SnS. For p-type carriers ZT is enhanced 1.4 times at 3% applied BT strain as compared to that of unstrained SnS. However, for n-type carriers, ZT does not change drastically with increase in BT strain. 相似文献
13.
S. Boughdachi Y. Azizian-Kalandaragh Ş. Altındal 《Journal of Electronic Materials》2018,47(12):6945-6953
In this research, bismuth sulfide nanostructures were prepared in the presence of polyvinyl alcohol (PVA) as a capping agent by an ultrasound-assisted method. The x-ray diffraction results show the crystalline phase of the sample and the mean crystalline size estimated by Debye–Scherer’s equation. The UV–Vis absorption spectrum show that the optical absorbance edge of Bi2S3 nanostructure was blue-shifted. The Fourier transform infrared spectra confirm the presence of PVA in the sample and transmission electron microscopy imaging shows that the structures are in nanoscale. The semi-logarithmic forward bias I–V plots have two distinct linear regimes for each temperature which are called low- and moderate-bias regions (LBR and MBR). In order to effectively interpret possible current-conduction/transport mechanisms, the reverse saturation current (Io), ideality factor (n) and zero-bias barrier height (ΦBO) were obtained from the slope and intercept of these plots and they were found to be a strong function of temperature and voltage. The high value of n even at high temperature and the increase of ΦBO with increasing temperature for the two regions is clear evidence of the deviation from thermionic emission (TE) theory. Therefore, ΦBO versus n and q/2kT plots were drawn to get evidence of the Gaussian distribution (GD) of the barrier height (BH) and they show a linear behavior. The mean values of BH (\( \bar{\Phi }_{\rm{BO}} \)) and standard deviation (σs) were also obtained from the intercepts and slopes of the ΦBO versus q/2kT plots as 1.44 eV and 0.19 V for the LBR and 1.32 eV and 0.18 V for the MBR, respectively. After that, the values \( \bar{\Phi }_{\rm{BO}} \) and effective Richardson constant (A*) were obtained as 1.29 eV and 267.6 A/(cm K)2 for the LBR and 1.27 eV and 281.7 A/(cm K)2 for the MBR, respectively. Such non-ideal I–V–T characteristics for the Al/(PVA-Bi2S3)/p-Si structure can be successfully explained by the single GD of BH for the LBR and MBR. 相似文献
14.
Sh. O. Eminov 《Semiconductors》2016,50(8):1005-1009
The optical absorption coefficient α in p+-InSb layers (with hole concentrations of p ≈ 1 × 1017–1.2 × 1019 cm–3), grown by liquid-phase epitaxy on p-InSb substrates, is measured in the spectral range of 5-12 µm at 90 K, and the impurity photoconductivity is measured (at 60 and 90 K) in p+–p structures. It is found that a in the p+ layers reaches a value of 7000 cm–1 (at p ≈ 2 × 1019 cm–1). It is shown that the measured substrate value of (α ≈1–3 cm–1) is overestimated in comparison with estimates (α ≈ 0.1 cm–1) based on comparing the photoconductivity data. This discrepancy is explained by the fact that the optical transitions of holes responsible for photoconductivity are obscured by the excitation of electrons to the conduction band. The photoionization cross section for these transitions does not exceed 1 × 10–15 cm2. 相似文献
15.
Undoped mid-wave infrared Hg1?xCdxSe epitaxial layers have been grown to a nominal thickness of 8–14 μm on GaSb (211)B substrates by molecular beam epitaxy (MBE) using constant beam equivalent pressure ratios. The effects of growth temperature from 70°C to 120°C on epilayer quality and its electronic parameters has been examined using x-ray diffraction (XRD) rocking curves, atomic force microscopy, Nomarski optical imaging, photoconductive decay measurements, and variable magnetic field Hall effect analysis. For samples grown at 70°C, the measured values of XRD rocking curve full width at half maximum (FWHM) (116 arcsec), root mean square (RMS) surface roughness (2.7 nm), electron mobility (6.6?×?104 cm2 V?1 s?1 at 130 K), minority carrier lifetime (~?2 μs at 130 K), and background n-type doping (~?3?×?1016 cm?3 at 130 K), indicate device-grade material quality that is significantly superior to that previously published in the open literature. All of these parameters were found to degrade monotonically with increasing growth temperature, although a reasonably wide growth window exists from 70°C to 90°C, within which good quality HgCdSe can be grown via MBE. 相似文献
16.
T. Okuda T. Miyazawa H. Tsuchida T. Kimoto J. Suda 《Journal of Electronic Materials》2017,46(11):6411-6417
We investigated limiting factors of carrier lifetimes and their enhancement by post-growth processes in lightly-doped p-type 4H-SiC epitaxial layers (N A ~ 2 × 1014 cm?3). We focused on bulk recombination, surface recombination, and interface recombination at the epilayer/substrate, respectively. The carrier lifetime of 2.8 μs in an as-grown epilayer was improved to 10 μs by the combination of VC-elimination processes and hydrogen annealing. By employing surface passivation with deposited SiO2 followed by POCl3 annealing, a long carrier lifetime of 16 μs was obtained in an oxidized epilayer. By investigating carrier lifetimes in a self-standing p-type epilayer, it was revealed that the interface recombination at the epilayer/substrate was smaller than the surface recombination on a bare surface. We found that the VC-elimination process, hydrogen annealing, and surface passivation are all important for improving carrier lifetimes in lightly-doped p-type epilayers. 相似文献
17.
The results of an experimental study of the capacitance–voltage (C–V) characteristics and deep-level transient spectroscopy (DLTS) spectra of p+–p0–i–n0 homostructures based on undoped dislocationfree GaAs layers and InGaAs/GaAs and GaAsSb/GaAs heterostructures with homogeneous networks of misfit dislocations, all grown by liquid-phase epitaxy (LPE), are presented. Deep-level acceptor defects identified as HL2 and HL5 are found in the epitaxial p0 and n0 layers of the GaAs-based structure. The electron and hole dislocation-related deep levels, designated as, respectively, ED1 and HD3, are detected in InGaAs/GaAs and GaAsSb/GaAs heterostructures. The following hole trap parameters: thermal activation energies (E t ), capture cross sections (σ p ), and concentrations (N t ) are calculated from the Arrhenius dependences to be E t = 845 meV, σ p = 1.33 × 10–12 cm2, N t = 3.80 × 1014 cm–3 for InGaAs/GaAs and E t = 848 meV, σ p = 2.73 × 10–12 cm2, N t = 2.40 × 1014 cm–3 for GaAsSb/GaAs heterostructures. The concentration relaxation times of nonequilibrium carriers are estimated for the case in which dislocation-related deep acceptor traps are involved in this process. These are 2 × 10–10 s and 1.5 × 10–10 s for, respectively, the InGaAs/GaAs and GaAsSb/GaAs heterostructures and 1.6 × 10–6 s for the GaAs homostructures. 相似文献
18.
The interface properties of a Au/n-GaN Schottky junction (SJ) were modified by placing a high-k barium strontium titanate (Ba0.6Sr0.4TiO3) insulating layer between the Au and n-GaN semiconductor. The surface morphology, chemical composition, and electrical properties of Au/Ba0.6Sr0.4TiO3 (BST)/n-GaN metal/insulator/semiconductor (MIS) junctions were explored by atomic force microscopy, energy-dispersive x-ray spectroscopy, current–voltage (I–V) and capacitance–voltage (C–V) techniques. The electrical results of the MIS junction are correlated with the SJ and discussed further. The MIS junction exhibited an exquisite rectifying nature compared to the SJ. An average barrier height (BH) and ideality factors were extracted to be 0.77 eV, 1.62 eV and 0.92 eV, 1.95 for the SJ and MIS junction, respectively. The barrier was raised by 150 meV for the MIS junction compared to the MS junction, implying that the BH was effectively altered by the BST insulating layer. The BH values extracted by I–V, Cheung’s and Norde functions were nearly equal to one another, indicating that the techniques applied here were dependable and suitable. The frequency-dependent properties of the SJ and MIS junction were explored and discussed. It was found that the interface state density of the MIS junction was smaller than the SJ. This implies that the BST layer plays an imperative role in the decreased NSS. Poole–Frenkel emission was the prevailed current conduction mechanism in the reverse-bias of both the SJ and MIS junction. 相似文献
19.
A. E. Belyaev N. S. Boltovets V. N. Ivanov V. P. Klad’ko R. V. Konakova Ya. Ya. Kudrik A. V. Kuchuk V. V. Milenin Yu. N. Sveshnikov V. N. Sheremet 《Semiconductors》2008,42(6):689-693
A mechanism of charge transport in Au-TiB x -n-GaN Schottky diodes with a space charge region considerably exceeding the de Broglie wavelength in GaN is studied. Analysis of temperature dependences of current-voltage (I–V) characteristics of forward-biased Schottky barriers showed that, in the temperature range 80–380 K, the charge transport is performed by tunneling along dislocations intersecting the space charge region. Estimation of dislocation density ρ by the I–V characteristics, in accordance with a model of tunneling along the dislocation line, gives the value ρ ≈ 1.7 × 107 cm?2, which is close in magnitude to the dislocation density measured by X-ray diffractometry. 相似文献
20.
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