Application of WACBED to superlattice structures in compound semiconductors

1987 ◽  
Vol 45 ◽  
pp. 44-45
Author(s):  
S. McKernan
Keyword(s):  
Lattice Mismatch ◽  
Compound Semiconductors ◽  
Real Space ◽  
Chemical Difference ◽  
Lattice Matching ◽  
Large Lattice ◽  
Strained Layer Superlattice ◽  
Large Lattice Mismatch ◽  
Superlattice Structures ◽  
The Individual

Superlattice structures are now routinely grown in compound semiconductors, with superlattice periodicities ranging from a few angstroms to several hundred angstroms. The structures consist of alternating layers of compound semiconductor which have different chemical composition. The composition of the layers may be chosen to provide a relatively large lattice mismatch for a strained layer superlattice, or to provide lattice matching for good epitactic growth. The chemical difference may be large, as in AIAs/GaAs for example or may be represent only a change in concentration of substitutionally doped material. In all of these materials it is important to characterize the material of the individual layers as well as the interface between these layers.Microscopy of these materials has been performed in real space, using both high resolution and diffraction contrast techniques, and in reciprocal space. The thin cross section specimens used in these investigations are affected by stress relaxation at the interfaces which can result in bending of the atomic planes near the interface.

Coherent and Incoherent Relaxation in III-V Heterostructures

1999 ◽  
Vol 594 ◽  
Author(s):  
André Rocher ◽  
Etienne Snoeck
Keyword(s):  
Lattice Mismatch ◽  
Growth Front ◽  
Relaxation Mechanism ◽  
Gaas Layer ◽  
Large Lattice ◽  
Limited Length ◽  
Large Lattice Mismatch ◽  
The Individual ◽  
Square Array ◽  
The Ideal

AbstractThe relaxation for large lattice mismatch systems such as GaSb/GaAs and GaAs/InP has been studied by numerical analysis of HREM images. The GaSb/GaAs epitaxial system can be obtained with an interface constituted by a perfect square array of Lomer dislocations. GaSb appears to be coherently and homogeneously relaxed. For GaAs/InP grown at 450°C the GaAs layer becomes well relaxed at some distances from the interface by a network of randomly distributed partial and 60° dislocation segments with a limited length. At low temperature, the plastic relaxation appears directly at the growth front when the individual adatoms take a position different from the ideal pseudomorphic one. In this case, the relaxation mechanism is incoherent.

Growth of GaAs on Si and its Application to FETs and LEDs

1986 ◽  
Vol 67 ◽  
Author(s):  
Masahiro Akiyama ◽  
Yoshihiro Kawarada ◽  
Seiji Nishi ◽  
Takashi Ueda ◽  
Katsuzo Kaminishi
Keyword(s):  
Buffer Layer ◽  
Lattice Mismatch ◽  
Antiphase Domain ◽  
Thin Layers ◽  
The Other ◽  
Heteroepitaxial Growth ◽  
Si Substrates ◽  
Large Lattice ◽  
Strained Layer Superlattice ◽  
Large Lattice Mismatch

In recent years, the heteroepitaxial growth of GaAs layers on Si substrates has been gained an increasing interest [1 - 14]. GaAs is one of the most important III-V materials and has been well studied and used for optical and electrical devices. On the other hand, with Si we have large size wafers of superior quality and sophisticated technologies and Si is a main material for semiconductor industries. Therefore, GaAs/Si system has possibilities for realizing new types of functional devices or ICs with GaAs and Si devices. This system, however, has two serious problems. One is the large lattice mismatch of about 4 % between these materials and the other is the polar on nonpolar problem i.e., the formation of an antiphase domain disorder. It was reported that when (211)-oriented Si substrates were used, there was no problem of the formation of an antiphase domain structure 5. For growing materials on lattice mismatched substrates, it was reported that the thin layers deposited at low temperatures were effective to relax the lattice mismatches for the systems such as SiC on Si[15] and Si on saphire [16]. In GaAs/Si system, the Ge buffer layer has been used to relax the lattice mismatch[17 - 22] It was also reported that the composite strained layer superlattice with GaP/GaAsP and GaAsP/GaAs was very effective as a buffer layer[23 - 25].

scholarly journals Structure Transformation and Coherent Interface in Large Lattice-Mismatched Nanoscale Multilayers

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
J. Y. Xie ◽  
F. Wang ◽  
P. Huang ◽  
T. J. Lu ◽  
L. F. Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lattice Mismatch ◽  
High Resolution Electron Microscopy ◽  
Face Centered Cubic ◽  
Individual Layer ◽  
Structure Transition ◽  
Large Lattice ◽  
Large Lattice Mismatch ◽  
Face Centered ◽  
The Individual

Nanoscale Al/W multilayers were fabricated by DC magnetron sputtering and characterized by transmission electron microscopy and high-resolution electron microscopy. Despite the large lattice mismatch and significantly different lattice structures between Al and W, a structural transition from face-centered cubic to body-centered cubic in Al layers was observed when the individual layer thickness was reduced from 5 nm to 1 nm, forming coherent Al/W interfaces. For potential mechanisms underlying the observed structure transition and forming of coherent interfaces, it was suggested that the reduction of interfacial energy and high stresses induced by large lattice-mismatch play a crucial role.

scholarly journals Enhanced luminescence/photodetecting bifunctional devices based on ZnO:Ga microwire/p-Si heterojunction by incorporating Ag nanowires

2021 ◽  
Author(s):  
Mingming Jiang ◽  
Yang Liu ◽  
Ruiming Dai ◽  
Kai Tang ◽  
Peng Wan ◽  
...  
Keyword(s):  
Band Gap ◽  
Carrier Mobility ◽  
Lattice Mismatch ◽  
Semiconductor Materials ◽  
Large Lattice ◽  
Ag Nanowires ◽  
Large Lattice Mismatch ◽  
Enhanced Luminescence ◽  
Indirect Band Gap

Suffering from the indirect band gap, low carrier mobility, and large lattice mismatch with other semiconductor materials, one of the current challenges in Si-based materials and structures is to prepare...

Epitaxial Growth of Copper, Silver and Gold on a Semiconducting Layered Material: Tungsten Disulfide

1987 ◽  
Vol 102 ◽  
Author(s):  
D. L. Doering ◽  
F. S. Ohuchi ◽  
W. Jaegermann ◽  
B. A. Parkinson
Keyword(s):  
Thin Films ◽  
Epitaxial Growth ◽  
Lattice Mismatch ◽  
Layered Material ◽  
Tungsten Disulfide ◽  
Layer By Layer ◽  
Metal Contacts ◽  
Layered Semiconductor ◽  
Large Lattice ◽  
Large Lattice Mismatch

ABSTRACTThe growth of copper, silver and gold thin films on tungsten disulfide has been examined as a model of metal contacts on a layered semiconductor. All three metals were found to grow epitaxially on the WS2. However, Cu appears to form a discontinuous film while Au and Ag grow layer by layer. Such epitaxial growth is somewhat surprising since there is a large lattice mismatch between the metals and the WS2.

III-V monolithic resonant photoreceiver using local epitaxy and large lattice mismatch material

1991 ◽  
Vol 4 (6) ◽  
pp. 217-219 ◽  
Author(s):  
S. Aboulhouda ◽  
J. P. Vilcot ◽  
M. Razeghi ◽  
D. Decoster ◽  
M. Francois ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
Large Lattice ◽  
Large Lattice Mismatch

Equilibrium Analysis of Lattice-Mismatched Nanowire Heterostructures

2002 ◽  
Vol 737 ◽  
Author(s):  
E. Ertekin ◽  
P.A. Greaney ◽  
T. D. Sands ◽  
D. C. Chrzan
Keyword(s):  
Simple Model ◽  
Misfit Dislocation ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Equilibrium Analysis ◽  
Misfit Dislocations ◽  
Model Based ◽  
Large Lattice ◽  
Large Lattice Mismatch

ABSTRACTThe quality of lattice-mismatched semiconductor heterojunctions is often limited by the presence of misfit dislocations. Nanowire geometries offer the promise of creating highly mismatched, yet dislocation free heterojunctions. A simple model, based upon the critical thickness model of Matthews and Blakeslee for misfit dislocation formation in planar heterostructures, illustrates that there exists a critical nanowire radius for which a coherent heterostructured nanowire system is unstable with respect to the formation of misfit dislocations. The model indicates that within the nanowire geometry, it should be possible to create perfect heterojunctions with large lattice-mismatch.

scholarly journals Epitaxial Growth of Germanium on Silicon for Light Emitters

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Chengzhao Chen ◽  
Cheng Li ◽  
Shihao Huang ◽  
Yuanyu Zheng ◽  
Hongkai Lai ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Near Infrared ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Sige Layer ◽  
Infrared Light ◽  
Multiple Quantum ◽  
Light Emitters ◽  
Large Lattice ◽  
Large Lattice Mismatch

This paper describes the role of Ge as an enabler for light emitters on a Si platform. In spite of the large lattice mismatch of ~4.2% between Ge and Si, high-quality Ge layers can be epitaxially grown on Si by ultrahigh-vacuum chemical vapor deposition. Applications of the Ge layers to near-infrared light emitters with various structures are reviewed, including the tensile-strained Ge epilayer, the Ge epilayer with a delta-doping SiGe layer, and the Ge/SiGe multiple quantum wells on Si. The fundamentals of photoluminescence physics in the different Ge structures are discussed briefly.

Nucleation of misfit and threading dislocations in GaSb/GaAs(001) heterostructure

1996 ◽  
Vol 54 ◽  
pp. 946-947
Author(s):  
W. Qian ◽  
M. Skowronski ◽  
R. Kaspi ◽  
M. De Graef
Keyword(s):  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Extended Defects ◽  
Large Lattice ◽  
Threading Dislocation Density ◽  
Small Lattice ◽  
Large Lattice Mismatch

GaSb thin film grown on GaAs is a promising substrate for fabrication of electronic and optical devices such as infrared photodetectors. However, these two materials exhibit a 7.8% lattice constant mismatch which raises concerns about the amount of extended defects introduced during strain relaxation. It was found that, unlike small lattice mismatched systems such as InxGa1-xAs/GaAs or GexSi1-x/Si(100), the GaSb/GaAs interface consists of a quasi-periodic array of 90° misfit dislocations, and the threading dislocation density is low despite its large lattice mismatch. This paper reports on the initial stages of GaSb growth on GaAs(001) substrates by molecular beam epitaxy (MBE). In particular, we discuss the possible formation mechanism of misfit dislocations at the GaSb/GaAs(001) interface and the origin of threading dislocations in the GaSb epilayer.GaSb thin films with nominal thicknesses of 5 to 100 nm were grown on GaAs(001) by MBE at a growth rate of about 0.8 monolayers per second.

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