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1.
J.E. Ayers 《Journal of Electronic Materials》2008,37(10):1511-1523
This review paper presents important findings relative to the use of compliant substrates for mismatched heteroepitaxial devices,
including the theoretical background, experimental results, and the directions for current efforts. Theories for relative
compliance and absolute compliance are presented. Key experimental results are summarized for a number of compliant substrate
technologies, including cantilevered membranes, silicon-on-insulator, twist bonding, and glass bonding. Two approaches of
current interest, layer transfer and universal compliant trench (UCT) substrates, are presented as potential solutions to
the problem of limited absolute compliance in planar compliant substrates attached to handle wafers. 相似文献
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C. Carter-Coman A. S. Brown N. M. Jokerst D. E. Dawson R. Bicknell-Tassius Z. C. Feng K. C. Rajkumar G. Dagnall 《Journal of Electronic Materials》1996,25(7):1044-1048
Compliant substrates allow a new approach to the growth of strained epitaxial layers, in which part of the strain is accommodated
in the substrate. In this article, compliant substrates are discussed and a new compliant substrate technology based on bonded
thin film substrates is introduced. This technology has several advantages over previously published methods, including the
ability to pattern both the top and bottom of the material. A new concept enabled by this compliant substrate technology,strain-modulated epitaxy, will be introduced. Using this technique, the properties of the semiconductor material can be controlled laterally across
a substrate. Results of two experiments are presented in which low composition InxGa1−xAs was grown by molecular beam epitaxy on GaAs compliant substrates at thicknesses both greater than and less than the conventional
critical thickness. It was found that for t > tc, there was an inhibition of defect production in the epitaxial films grown on the compliant substrates as compared to those
grown on conventional reference substrates. For t < tc, photoluminescence and x-ray diffraction show the compliant substrates to be of excellent quality and uniformity as compared
to conventional substrates. 相似文献
4.
Y. Zheng P. D. Moran Z. F. Guan S. S. Lau D. M. Hansen T. F. Kuech T. E. Haynes T. Hoechbauer M. Nastasi 《Journal of Electronic Materials》2000,29(7):916-920
Many GaSb devices would greatly benefit from the availability of a semi-insulating substrate. Since semi-insulating GaSb is
not currently available, the formation of thin GaSb layers through wafer bonding and tranfer onto a semi-insulating GaAs substrate
was investigated. GaSb-on-insulator structures, formed on GaAs substrates, were realized by the ion-cut process using H+ ions. Blistering, bonding and layer splitting phenomena were studied to optimize the ion dose and the process window. Bonded
structures of thin layers of GaSb bonded to GaAs wafers were formed using a borosilicate glass (BSG) layer. The transferred
GaSb layers were characterized by atomic force microscopy, MeV helium ion channeling and high-resolution x-ray diffractometry.
The transferred film possessed a narrow x-ray linewidth of about 140 arcsec indicating improved crystalline quality over the
direct growth of GaSb on GaAs. 相似文献
5.
The microstructure of as-deposited Co thin films on silicon (001) substrate was characterized by TEM using wedge-shaped planar-view
samples. Selected area electron diffraction showed that the as deposited Co thin films were composed of Co (α) and that no
interfacial reaction took place between Co thin films and the Si substrate. The microstructure of Co thin films annealed at
250°C for 30 min was also investigated by using conventional planar-view samples. The analysis of selected area electron diffraction
indicates that Co thin films react entirely with the Si substrate, and a silicide layer forms at the Co/Si interface. Dark
field images clearly indicate that the interfacial layer consists of Co2Si in irregular stripes and CoSi as fine particles but no CoSi2 forms. 相似文献
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Evolution of ZnO nanostructures on silicon substrate by vapor-solid mechanism: Structural and optical properties 总被引:1,自引:0,他引:1
ZnO nanostructures with different morphologies and sizes were synthesized on silicon substrate simply by the thermal evaporation
of high-purity metallic zinc powder in the presence of oxygen without the use of any catalyst or additives. It was observed
that the substrate temperature and the distance of the substrate from the source material play a critical role to determine
the morphologies and sizes of the deposited structures. Scanning electron microscopic observations revealed that different
types of nano- and microstructures, such as ZnO pyramid-shaped nanotowers, nanowires attached with the sheet-like structures,
nanorods, microcages, and microtubes were obtained at different temperature zones with specific distances of the substrate
from the source material. High-resolution transmission electron microscopy and x-ray diffraction studies confirm that the
deposited products are single crystalline with wurtzite hexagonal structures. The room-temperature photoluminescence spectra
of all the deposited structures displayed a strong near-band-edge emission with negligible green emission. 相似文献
8.
Antonio M. Mio Philipp M. Konze Alexander Meledin Michael Küpers Marc Pohlmann Marvin Kaminski Richard Dronskowski Joachim Mayer Matthias Wuttig 《Advanced functional materials》2019,29(37)
Phase‐change materials for high‐density data storage traditionally exploit the amorphous‐to‐crystalline phase transition. A number of these compounds are organized in blocks, separated by van der Waals‐like gaps. Such layered chalcogenides are attracting interest due to their unique material properties and the possibility to change their properties upon local rearrangements at the gap, giving rise to novel applications. To better understand the behavior of layered chalcogenides, the connection between structural defects, physical properties, and the bonding situation is highlighted here using electron microscopy, X‐ray diffraction, and density functional theory. In particular, stacking defects in hexagonal Ge4Se3Te, GaSe, and Sb2Te3 are characterized experimentally, followed by an investigation of the influence of observed and hypothetical stacking defects on optical and electronic properties by theoretical means. Then, a connection between observed defects and the bonding situation in these materials is drawn and related to the presence of van der Waals and metavalent bonding in chalcogenides. Finally, additional experiments are performed to validate the conclusions for other metavalently bonded layered chalcogenides. Transmission electron microscopy provides a powerful tool for direct detection of defects and, when combined with diffraction experiments and ab initio theory, it facilitates the precise investigation of the bonding mechanisms in layered chalcogenides. 相似文献
9.
T. George W. T. Pike M. A. Khan J. N. Kuznia P. Chang-Chien 《Journal of Electronic Materials》1995,24(4):241-247
The initial growth by low pressure metalorganic chemical vapor deposition and subsequent thermal annealing of A1N and GaN
epitaxial layers on SiC and sapphire substrates is examined using high resolution transmission electron microscopy and atomic
force microscopy. Growth under low pressure conditions on sapphire substrates is significantly different from that reported
for conventional (atmospheric pressure) conditions. Smooth, single crystal A1N and GaN layers were deposited on sapphire in
the initial low temperature (600°C) growth step. Interfacial bonding and not lattice mismatch was found to be the determin
ing factor for obtaining good crystallinity for the epitaxial layers as indicated by the growth results on SiC substrates. 相似文献
10.
Energy-filtered transmission electron microscopy (EFTEM) was used to study 6H-SiC/SiO2 interfaces produced by thermal oxidation as a function of the oxidation conditions. Elemental maps of C and Si were used
to calculate C-to-Si concentration profiles across the interfaces. Enhanced C/Si concentrations (up to ∼ 35%) were observed
at distinct regions in samples oxidized at 1100°C for 4 h in a wet ambient. The data from a number of randomly selected regions
indicate that re-oxidation at 950°C for 3 h significantly reduced, but did not eliminate, the amount of excess interfacial
carbon. 相似文献
11.
Maria Eugenia Toimil‐Molares Lars Röntzsch Wilfried Sigle Karl‐Heinz Heinig Christina Trautmann Reinhard Neumann 《Advanced functional materials》2012,22(4):695-701
The most interesting applications of nanotubes include their use as storage media for atoms and small molecules, as nanoscale capsules for chemical reactions, and as nanopipettes for material delivery. The geometrical transformation of metallic copper nanowires, confined in graphitic coating, into crystalline nanoparticles of up to tenfold increased diameter is reported. In situ transmission electron microscopy images at 500 °C, recorded as movies, provide an exceptional real‐time visualization of Cu draining out of the carbon coating. The solid content of the carbon tube is effectively evacuated over micrometer distances towards the open end, transforming each nanowire into a single monocrystalline, facetted Cu particle. Kinetic Monte Carlo simulations propose that this dramatic morphological transformation is driven by surface diffusion of Cu atoms along the wire/tube interface, thus minimizing the total free energy of the system. 相似文献
12.
Amer Hamidi‐Sakr Laure Biniek Sadiara Fall Martin Brinkmann 《Advanced functional materials》2016,26(3):408-420
Precise control of orientation and crystallinity is achieved in regioregular poly(3‐hexylthiophene) (P3HT) thin films by using high‐temperature rubbing, a fast and effective alignment method. Rubbing P3HT films at temperatures TR ≥ 144 °C generates highly oriented crystalline films with a periodic lamellar morphology with a dichroic ratio reaching 25. The crystallinity and the average crystal size along the chain axis direction, lc, are determined by high‐resolution transmission electron microscopy and differential scanning calorimetry. The inverse of the lamellar period l scales with the supercooling and can accordingly be controlled by the rubbing temperature TR. Uniquely, the observed exciton coupling in P3HT crystals is correlated to the length of the average planarized chain segments lc in the crystals. The high alignment and crystallinity observed for TR > 200 °C cannot translate to high hole mobilities parallel to the rubbing because of the adverse effect of amorphous zones interrupting charge transport between crystalline lamellae. Although tie chains bridge successive P3HT crystals through amorphous zones, their twisted conformation restrains interlamellar charge transport. The evolution of charge transport anisotropy is correlated to the evolution of the dominant contact plane from mainly face‐on (TR ≤ 100 °C) to edge‐on (TR ≥ 170 °C). 相似文献
13.
利用可控的电子束辐照减薄,成功地在电子显微镜内原位制备出石墨烯。由于从单张高分辨像上难以分辨单个碳原子,本文采集了系列离焦的高分辨像并进行波函数重构,最终获得了清晰的单个碳原子像。系列像的重构是利用自主开发的REW软件实现的,本文介绍如何利用REW的像模拟功能确定系列像的成像条件。 相似文献
14.
J. Pamulapati P. K. Bhattacharya J. Singh P. R. Berger C. W. Snyder B. G. Orr R. L. Tober 《Journal of Electronic Materials》1996,25(3):479-483
We confirm that as the misfit strain in pseudomorphic epitaxial layer increases, surface thermodynamics controlled growth
modes can change from a layer-by-layer to a three-dimensional (3-D) island mode. Both in-situ reflection high energy electron
diffraction studies and in-situ scanning tunneling microscopy studies are utilized to demonstrate this transition to 3-D growth.
This concept allows one to grow GaAs/InxGa1-xAs/GaAs heterostructures where the electrons in InxGa1-xAs are possibly confined in lower dimensions. 相似文献
15.
Changzhen Wang Steve Tobin Themis Parodos David J. Smith 《Journal of Electronic Materials》2006,35(6):1192-1196
The microstructure of p-n device structures grown by liquid-phase epitaxy (LPE) on CdZnTe substrates has been evaluated using
transmission electron microscopy (TEM). The devices consisted of thick (∼21-μm) n-type layers and thin (∼1.6-μm) p-type layers,
with final CdTe (∼0.5 μm) passivation layers. Initial observations revealed small defects, both within the n-type layer (doped
with 8×1014/cm3 of In) and also within the p-type layer but at a much reduced level. These defects were not visible, however, in cross-sectional
samples prepared by ion milling with the sample held at liquid nitrogen temperature. Only isolated growth defects were observed
in samples having low indium doping levels (2×1014/cm3). The CdTe passivation layers were generally columnar and polycrystalline, and interfaces with the p-type HgCdTe layers were
uneven. No obvious structural changes were apparent in the region of the CdTe/HgCdTe interfaces as a result of annealing at
250°C. 相似文献
16.
本文研究了斜切割(100)Ge衬底上InxGa1-xAs/GaAs量子阱结构的分子束外延生长(In组分为0.17或者0.3)。所生长的样品用原子力显微镜、光致发光光谱和高分辨率透射电子显微镜进行了测量和表征。结果发现,为了生长没有反相畴的GaAs缓冲层,必须对Ge衬底进行高温退火。在GaAs外延层和InxGa1-xAs/GaAs量子阱结构的生长过程中,生长温度是一个至关重要的参数。文中讨论了温度对于外延材料质量的影响机理。通过优化生长温度,Ge衬底上的InxGa1-xAs/GaAs量子阱结构的光致发光谱具有很高的强度、很窄的线宽,样品的表面光滑平整。这些研究表面Ge 衬底上的III-V族化合物半导体材料有很大的器件应用前景。 相似文献
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Molecular beam epitaxy growth of an InxGa1-xAs/GaAs quantum well(QW) structure(x equals to 0.17 or 0.3) on offcut(100) Ge substrate has been investigated.The samples were characterized by atomic force microscopy,photoluminescence(PL),and high resolution transmission electron microscopy.High temperature annealing of the Ge substrate is necessary to grow GaAs buffer layer without anti-phase domains.During the subsequent growth of the GaAs buffer layer and an InxGa1-xAs/GaAs QW structure,temperature plays a key role. The mechanism by which temperature influences the material quality is discussed.High quality InxGa1-x As/GaAs QW structure samples on Ge substrate with high PL intensity,narrow PL linewidth and flat surface morphology have been achieved by optimizing growth temperatures.Our results show promising device applications forⅢ-Ⅴcompound semiconductor materials grown on Ge substrates. 相似文献
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重度污染天气下大气颗粒物PM_(1.0)物理化学特征的透射电子显微镜研究 总被引:1,自引:0,他引:1
大气颗粒物样品采自徐州市区2013年12月~2014年1月间重度污染天气。采样期间PM1.0主要由烟尘颗粒、复合酸冷凝颗粒、硫酸盐颗粒、矿物颗粒、金属及金属氧化物颗粒等组成。本文通过透射电子显微镜(TEM)及能谱仪(EDS)给出的大气颗粒物PM1.0高分辨结构信息、颗粒相尺寸及化学相尺寸信息、颗粒相中不同化学相嵌布特征信息等,对组成颗粒相的化学相连生关系进行了比较系统的分析研究。分析数据表明,大气颗粒物PM1.0的颗粒模态转变过程与颗粒物形成过程的相关性较强。异相凝结颗粒中化学相物质结构类型的判别是识别颗粒成因及形成过程的重要因素。 相似文献