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101.
Z. -Q. Fang B. Claflin D. C. Look L. Polenta W. C. Mitchel 《Journal of Electronic Materials》2005,34(4):336-340
High-purity semi-insulating (HPSI) 4H-SiC has been widely used as a substrate material for AlGaN/GaN high electron-mobility
transistors because of its fairly good lattice match with GaN and its high thermal conductivity. To control material quality,
it is important to understand the nature of the deep traps. For this purpose, we have successfully applied thermally stimulated
current (TSC) spectroscopy to investigate deep traps in two HPSI 4H-SiC samples grown by physical vapor transport (PVT) and
high-temperature chemical vapor deposition (HTCVD), respectively. Fundamentals of TSC spectroscopy, typical TSC spectra obtained
on the two samples, and theoretical fittings of a boron-related trap (peaked at ∼ 150 K) will be presented. Based on literature
data for deep traps in conductive 4H-SiC, the impurity and point-defect nature of several commonly observed TSC traps, peaked at ∼105 K (0.22 eV), ∼150 K (0.29
eV), ∼175 K (∼0.33 eV), ∼260 K (∼0.53 eV), ∼305 K (∼0.63 eV), and ∼360 K (0.91 eV), in the HPSI 4H-SiC will be discussed. 相似文献
102.
Shuang-Shuang Kong Wei-Kai Liu Xiao-Xia Yu Ya-Lin Li Liu-Zhu Yang Yun Ma Xiao-Yong Fang 《Frontiers of Physics》2023,18(4):43302
Silicon carbide nanosheets (SiCNSs) have a very broad application prospect in the field of new two-dimensional (2D) materials. In this paper, the interlayer interaction mechanism of bilayer SiCNSs (BL-SiCNSs) and its effect on optical properties are studied by first principles. Taking the charge and dipole moment of the layers as parameters, an interlayer coupling model is constructed which is more convenient to control the photoelectric properties. The results show that the stronger the interlayer coupling, the smaller the band gap of BL-SiCNSs. The interlayer coupling also changes the number of absorption peaks and causes the red or blue shift of absorption peaks. The strong interlayer coupling can produce obvious dispersion and regulate the optical transmission properties. The larger the interlayer distance, the smaller the permittivity in the vertical direction. However, the permittivity of the parallel direction is negative in the range of 150-300 nm, showing obvious metallicity. It is expected that the results will provide a meaningful theoretical basis for further study of SiCNSs optoelectronic devices. 相似文献
103.
Over the past decades, the progress in the growth of materials which can be applied to cutting-edge technologies in the field of electronics, optoelectronics and energy harvesting has been remarkable. Among the various materials, group III–V semiconductors are of particular interest and have been widely investigated due to their excellent optical properties and high carrier mobility. However, the integration of III–V structures as light sources and numerous other optical components on Si, which is the foundation for most optoelectronic and electronic integrated circuits, has been hindered by the large lattice mismatch between these compounds. This mismatch results in substantial amounts of strain and degradation of the performance of the devices. Nanowires (NWs) are unique nanostructures that induce elastic strain relaxation, allowing for the monolithic integration of III–V semiconductors on the cheap and mature Si platform. A technique that ensures flexibility and freedom in the design of NW structures is the growth of ternary III–V NWs, which offer a tuneable frame of optical characteristics, merely by adjusting their nominal composition. In this review, we will focus on the recent progress in the growth of ternary III–V NWs on Si substrates. After analysing the growth mechanisms that are being employed and describing the effect of strain in the NW growth, we will thoroughly inspect the available literature and present the growth methods, characterization and optical measurements of each of the III–V ternary alloys that have been demonstrated. The different properties and special treatments required for each of these material platforms are also discussed. Moreover, we will present the results from the works on device fabrication, including lasers, solar cells, water splitting devices, photodetectors and FETs, where ternary III–V NWs were used as building blocks. Through the current paper, we exhibit the up-to-date state in this field of research and summarize the important accomplishments of the past few years. 相似文献
104.
105.
S. Faulhaber M.-W. Moon A.G. Evans 《Journal of the mechanics and physics of solids》2006,54(5):1004-1028
Residually compressed films and coatings are susceptible to buckle delamination. The buckles often have linear or telephone cord morphology. When the films are brittle, such buckles are susceptible to the formation of ridge cracks that extend along their length, terminating close to the propagating front. The ridge-cracked buckles are invariably straight-sided (not telephone cord) and differ in width. Buckle delaminations of this type occur on flat and curved substrates: having greatest technological relevance in the latter. They occur not only in single layer films but also in multilayers, such as thermal barrier systems. Establishing the mechanics of ridge-cracked buckle delaminations for multilayers on curved substrates serves two purposes. (a) It allows the prediction of buckle delamination and spalling for technologically important systems. (b) It provides a test protocol for measuring properties such as the delamination toughness of the interface and the stresses in the layers. Both objectives are addressed in the article: the latter by devising an inverse algorithm. Implementation of the algorithm is demonstrated for diamond-like carbon films on planar glass substrates and a thermal barrier multilayer on a curved superalloy substrate. 相似文献
106.
Fang Liang Hejun Xu Zuoyuan Dong Yafeng Xie Chen Luo Yin Xia Jian Zhang Jun Wang Xing Wu 《半导体学报》2019,40(6):63-68
Two-dimensional(2D) transition metal dichalcogenides alloys are potential materials in the application of photodetectors over a wide spectral range due to their composition-dependent bandgaps. The study of bandgap engineering is important for the application of 2D materials in devices. Here, we grow the Mo1-xWxSe2 alloys on mica, sapphire and SiO2/Si substrates by chemical vapor deposition(CVD) method. Mo1-x Wx Se2 alloys are grown on the mica substrates by CVD method for the first time. Photoluminescence(PL) spectroscopy is used to investigate the effects of substrates and interlayer coupling force on the optical bandgaps of as-grown Mo1-xWxSe2 alloys. We find that the substrates used in this work have an ignorable effect on the optical bandgaps of as-grown Mo1-xWxSe2. The interlayer coupling effect on the optical bandgaps of as-grown Mo1-xWxSe2 is larger than the substrates effect. These findings provide a new way for the future study of the growth and physical properties of 2D alloy materials. 相似文献
107.
This paper briefly reviews the progress of crystal growth and crystal materials in China during recent years. 相似文献
108.
The growth of epitaxial films on featured substrates has an important device application in junction-confinement, double hetero-structure
light emitting diodes. These devices are presently grown by a liquid phase epitaxy process but growth by metalorganic chemical
vapor deposition is desirable because of MOCVD's superior surface quality, uniformity, and throughput. This paper describes
the effect of growth parameters on AlGaAs films deposited by atmospheric-pressure MOCVD into substrate holes typically made
in the fabrication of junction-confinement LEDs. MOCVD growth replicates the substrate features; it does not give a planar
surface over the holes. The behavior of epitaxy filling into holes is strongly dependent on growth temperature and total gas
flow and largely independent of substrate misorientation and the thickness of the layer grown. Wet-etched holes formed (ll0)-oriented
V-groove and dovetail-groove features on the hole circumference. Faceting of the MOCVD growth was seen on the wall with the
(111)A feature while smooth growth was seen on the etched (111)B surface.
Deceased. 相似文献
109.
Yue Zhao HongLi Suo Min Liu DanMin Liu YingXiao Zhang MeiLing Zhou 《Physica C: Superconductivity and its Applications》2006,440(1-2):10-16
Biaxially textured Ni–5 at.%W substrates have been prepared by cold rolling, followed by three different annealing routes. In this paper, the processes of melting Ni and W metals, flat rolling, various annealing methods are described in detail. The Ni–5 at.%W tapes annealed under either high vacuum or flowing Ar (7% H2) gas were characterized by X-ray pole figures, ODF, EBSD as well as AFM analysis. The texture analysis indicated that as fabricated tapes have a sharp cube texture formed after annealing at a wide temperature range of 800–1100 °C. The high quality of cube orientation on tapes was obtained after a two-step annealing (TSA), where the percentage of the cube texture component was as high as 93.5% within a misorientation angle smaller than 8° from EBSD analysis. Furthermore, it was also observed that the number of twin boundaries in this tape decreased with respect to that of tapes annealed both in vacuum and one-step gas annealing. From AFM on 1 μm2 areas, it was concluded that the roughness (RMS) on the tape surface reached 0.98 nm. 相似文献
110.
Interface reaction between Ni and amorphous SiC 总被引:1,自引:0,他引:1
Sungtae Kim J. H. Perepezko Z. Dong A. S. Edelstein 《Journal of Electronic Materials》2004,33(10):1064-1070
A Ni/amorphous SiC (a-SiC) multilayered sample was prepared by ion-beam sputtering and was used as a model system to study the stability of metal
contacts with a-SiC against interface reactions. The diffusion of Ni into the a-SiC layer as well as Si and C into the Ni layer takes place concurrently during the annealing process. An intermediate NiSi
phase was identified in the Ni solution layer because of diffusion of Si and C resulting from the decomposition of a-SiC. A phase selection diagram has been developed that accounts for nucleation of the NiSi phase from the Ni solution layer. 相似文献