Structural Studies of an InAs-GaAs Superlattice Alloy

1985 ◽  
Vol 47 ◽  
Author(s):  
M. C. Tamargo ◽  
R. Hull ◽  
L. H. Greene ◽  
J. R. Hayes ◽  
N. Tabatabaie ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
Layer Structure ◽  
Growth Conditions ◽  
Buffer Layers ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Large Lattice ◽  
Large Lattice Mismatch ◽  
Strained Layer Superlattices ◽  
Lattice Matched

ABSTRACTThin alternating layers of InAs and GaAs have been grown by MBE on buffer layers lattice matched to InP. The layer structure was evaluated by transmission electron microscopy (TEM) and low angle X-ray scattering. Commensurate epitaxial layers approximately 15Å thick were obtained in spite of the large lattice mismatch (7%). These results and their implication for growth conditions of strained-layer superlattices will be discussed.

Growth and Characterization of CuInSe2 Epitaxial Films for Device Applications

1996 ◽  
Vol 426 ◽  
Author(s):  
S. Niki ◽  
T. Kurafuji ◽  
P. J. Fons ◽  
I. Kim ◽  
O. Hellman ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
Free Exciton ◽  
Epitaxial Films ◽  
Cross Sectional ◽  
Residual Defect ◽  
Transmission Electron ◽  
Large Lattice ◽  
Device Applications ◽  
Large Lattice Mismatch ◽  
Lattice Matched

AbstractCuInSe2 (CIS) epitaxial layers have been grown on both GaAs (001) and In0.29Ga0.71 As pseudo lattice-matched substrates by molecular beam epitaxy, and characterized for device applications. Despite a large lattice mismatch of Δa/a˜2.2%, epitaxial growth of CuInSe2 has been demonstrated on GaAs (001) showing their film properties strongly dependent on the Cu/In ratio. In-rich films had a large number of twins on {112} planes, and were found to be heavily compensated. On the other hand, Cu-rich films showed distinct photoluminescence emissions indicating significantly higher film quality in comparison with In-rich films. Two dimensional reciprocal x-ray intensity area mapping and cross-sectional transmission electron microscopy showed the formation of an interfacial layer in the vicinity of the CuInSe2/GaAs interface resulting from the strain-induced interdiffusion between CuInSe2 and GaAs. Reduction in lattice mismatch to Δa/a˜0.2% by using In0.29Ga0.71As pseudo lattice-matched substrates made possible the growth of high quality CuInSe2 with predominant free exciton emissions in their photoluminescence spectra and with residual defect densities of as low as p˜l×1017cm-3 implying the growth of device quality CuInSe2 epitaxial films.

An X-ray scattering study on inverted Ge–Si huts grown at low temperatures

2004 ◽  
Vol 19 (4) ◽  
pp. 347-351
Author(s):  
J. Xu ◽  
X. S. Wu ◽  
B. Qian ◽  
J. F. Feng ◽  
S. S. Jiang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Lattice Strain ◽  
Lattice Mismatch ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Large Lattice ◽  
Scattering Study

Ge–Si inverted huts, which formed at the Si∕Ge interface of Si∕Ge superlattice grown at low temperatures, have been measured by X-ray diffraction, grazing incidence X-ray specular and off-specular reflectivities, and transmission electron microscopy (TEM). The surface of the Si∕Ge superlattice is smooth, and there are no Ge–Si huts appearing on the surface. The roughness of the surfaces is less than 3 Å. Large lattice strain induced by lattice mismatch between Si and Ge is found to be relaxed because of the intermixing of Ge and Si at the Si∕Ge interface.

Highly Mismatched Hetero-Epitaxial Growth of Cubic Sic on Si

1987 ◽  
Vol 97 ◽  
Author(s):  
Hiroyuki Matsunami
Keyword(s):  
Epitaxial Growth ◽  
Lattice Mismatch ◽  
Electronic Devices ◽  
Chemical Vapor ◽  
Buffer Layers ◽  
Optimum Conditions ◽  
Large Lattice ◽  
Impurity Doping ◽  
Large Lattice Mismatch

ABSTRACTSingle crystals of cubic SiC were hetero-epitaxially grown on Si by chemical vapor deposition (CVD) method. A carbonized buffer layer on Si is utilized to overcome the large lattice mismatch of 20 %. Optimum conditions to make the buffer layers and those structures are discussed. Crystal quality of the CVD grown cubic SiC is analyzed by using X-ray analyses and microscopic observations. Electrical properties controlled by impurity doping during epitaxial growth are described together with fundamental electronic devices.

Growth and properties of epitaxial PbSe on Si(111) and Si(100) without buffer layer

1995 ◽  
Vol 379 ◽  
Author(s):  
P. Müller ◽  
A.N. Tiwari ◽  
H. Zogg
Keyword(s):  
Buffer Layer ◽  
Lattice Mismatch ◽  
Infrared Detector ◽  
Device Fabrication ◽  
Buffer Layers ◽  
Silicon Substrates ◽  
High Quality ◽  
Si Substrates ◽  
Large Lattice ◽  
Large Lattice Mismatch

Narrow gap IV-VI materials like PbS, PbSnSe and PbSnTe are used for infrared detector device fabrication [1,2]. Earlier an intermediate Ila-fluoride buffer layer, which consisted of a BaF2/CaF2-stack of about 2000 Å thickness, was used to get epitaxial high quality layers on silicon substrates. This buffer is now reduced to a much thinner layer of only about 20 Å thick CaF2, regardless the large lattice mismatch between layer and substrate [3,4,5]. The question therefore arises if high quality IV-VI layers can be grown on Si-substrates without any buffer layer as e.g. in CdTe/Si or GaAs/Si systems.The aim of this work is to grow IV-VI layers directly on Si-substrates without any buffer layers to study the growth kinetics and epitaxial quality. PbSe was chosen as a representant of IV-VI materials, and layers were grown on (111)- and (100)-oriented silicon substrates.

scholarly journals N+ Irradiation and Substrate-Induced Variability in the Metamagnetic Phase Transition of FeRh Films

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 661
Author(s):  
Steven P. Bennett ◽  
Samuel W. LaGasse ◽  
Marc Currie ◽  
Olaf Van’t Erve ◽  
Joseph C. Prestigiacomo ◽  
...  
Keyword(s):  
Phase Transition ◽  
Surface Morphology ◽  
Epitaxial Film ◽  
Lattice Mismatch ◽  
Ion Irradiation ◽  
Growth Conditions ◽  
Large Lattice ◽  
Magnetron Sputter Deposition ◽  
Weber Type ◽  
Large Lattice Mismatch

Metamagnetic FeRh has been the focus of numerous studies for its highly unique antiferromagnetic (AF) to ferromagnetic (FM) metamagnetic transition. While this phase transition usually occurs above room temperature (often Tc > 400 K), both ion irradiation and strained epitaxial growth have been used to bring it to applicable temperatures. Nevertheless, cross sample variability is pervasive in these studies. Here we explore the optical and magnetic properties of 35 nm thick FeRh grown by magnetron sputter deposition simultaneously on two different single crystal substrates: epitaxially on MgO (001) and highly strained with large lattice mismatch on Al2O3 (1000). We then irradiate the epitaxial film with 5 keV N+ ions to introduce disorder (and to a lesser extent, modify chemical composition) without effecting the surface morphology. We find that the phase-transitional properties of both films are strikingly different due to the large lattice mismatch, despite being grown in tandem with nominally identical growth conditions including Fe/Rh stoichiometry, pressure, and temperature. We observe that N+ implantation lowers Tc by ~60 K, yielding a sample with nominally the same transition temperature as the non-epitaxial film on sapphire, yet with a significantly increased magnetic moment, a larger magnetization change and a more abrupt transition profile. We attribute these differences to the Volmer-Weber type growth mode induced by the sapphire substrate and the resulting rougher surface morphology.

Characterization of Interfacial Structure in Large Lattice Mismatch Heteroepitaxy: Ag/Si (111)

1990 ◽  
Vol 209 ◽  
Author(s):  
D.C. McKenna ◽  
G.-C. Wang ◽  
K. Rajan
Keyword(s):  
Lattice Mismatch ◽  
Interfacial Structure ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Interfacial Structures ◽  
Large Lattice ◽  
Large Lattice Mismatch ◽  
Diffraction Patterns

ABSTRACTThe interfacial structure of a large lattice mismatched (˜25%) (111) Ag-Si system was studied by using transmission electron diffraction (SADP - Selected Area Diffraction Pattern). The epitaxial films of Ag (600–1200Å) were grown by MBE on flat Si(111) and misoriented Si(1ll) surfaces. We have examined the interfacial structures of the Ag on 2° misoriented Si(111) using diffraction patterns of cross sectional view. Through a detail analysis of thelocation and shape of the diffraction spots, we can determine the epitaxial relationship between Ag and Si, the small tilt angle of Ag(111) planes withrespect to the misoriented Si(111), the period of the finite terrace size of the misoriented Si substrate, and the size of the ordered region in the Ag film. The O-lattice analysis developed by Bollmann has beenapplied to this interface andthe result is compared with the SADP observation.

Transmission electron microscopy observation and optical property of sol-gel derived LiNbO3 films

1996 ◽  
Vol 11 (12) ◽  
pp. 3152-3157 ◽  
Author(s):  
K. Terabe ◽  
A. Gruverman ◽  
Y. Matsui ◽  
N. Iyi ◽  
K. Kitamura
Keyword(s):  
Lattice Mismatch ◽  
Sol Gel ◽  
Misfit Dislocations ◽  
Microscopy Observation ◽  
Continuous Film ◽  
Transmission Electron ◽  
Large Lattice ◽  
Large Lattice Mismatch ◽  
Interface Structures ◽  
Optical Waveguiding

Crystallization behavior, defects, and interface structures of sol-gel derived LiNbO3 films on three kinds of substrates were examined. The nucleation was found to occur epitaxially at the interface between the film and the substrate. The continuous film is formed by coalescence of the island-like crystallites. When sapphire substrate is used, which has large lattice mismatch with the LiNbO3, the resulting film contains a large amount of micropores, twin structures, and misfit dislocations. On the other hand, while LiTaO3 and 5% MgO-doped LiNbO3 substrates with smaller mismatch are used as substrates, the films show no evidence of the formation of dislocations and twins. The film on 5% MgO-doped LiNbO3 substrate shows better optical waveguiding property.

Structural Effects in Al(111)/Si(111) Heteroepitaxy by Partially Ionized Beam Deposition α

1988 ◽  
Vol 116 ◽  
pp. 465-470 ◽  
Author(s):  
A. S. Yapsir ◽  
C.-H. Choi ◽  
S. N. Yang ◽  
T.-M. Lu ◽  
M. Madden ◽  
...  
Keyword(s):  
Single Crystal ◽  
Lattice Mismatch ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Atom Ratio ◽  
Transmission Electron ◽  
Large Lattice ◽  
Large Lattice Mismatch ◽  
Partially Ionized ◽  
Acceleration Voltage

AbstractSingle crystal Al(111) films were grown on Si(111) surface at room temperature under a conventional vacuum condition using the partially ionized beam (PIB) deposition technique. The Al films were deposited with an ion to atom ratio of about 0.3% and an acceleration voltage of 1 kV. Transmission electron microscopy (TEM) analysis showed that the as-deposited films were single crystal with certain density of dislocation networks. These dislocations disappeared following a heat treatment at 450°C for 30 min. From X-ray diffraction and TEM patterns, it was observed that the Al(111) was aligned to the substrate with Al<1l0>//Si<1l0>. Possible mechanisms of the PIB epitaxial growth and a novel structural defect that is unique to this large lattice mismatch system are discussed.

Alloying Buffer Layers in Colloidal CdSe/ZnS Core/Shell Nanocrystals

2014 ◽  
Vol 67 (6) ◽  
pp. 844
Author(s):  
Huichao Zhang ◽  
Yonghong Ye ◽  
Boping Yang ◽  
Li Shen ◽  
Yiping Cui ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Lattice Mismatch ◽  
Buffer Layers ◽  
Temperature Dependent ◽  
Spectroscopy Analysis ◽  
Cdse Core ◽  
Time Resolved ◽  
X Ray ◽  
Large Lattice ◽  
Large Lattice Mismatch

When a ZnS shell is coated onto a CdSe core, some non-radiative defects are formed with the relaxation of the strain induced by the large lattice mismatch between CdSe and ZnS even though there are Zn0.5Cd0.5Se or ZnSe buffer layers, as indicated by the decrease of photoluminescent (PL) quantum yield and the reverse evolution of temperature-dependent time-resolved PL decay. X-Ray photoelectron spectroscopy analysis reveals that these defects are induced by the formation of an interfacial alloy during the epitaxy process. These defects could be significantly suppressed if the ZnxCd1–xSeyS1–y alloy buffer layer is artificially introduced.

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