Structural Characterization of GaP/GaAs/GaP Heterostructure by TEM

1992 ◽  
Vol 280 ◽  
Author(s):  
G. Aragón ◽  
S. I. Molina ◽  
R. García
Keyword(s):  
Buffer Layer ◽  
Structural Characterization ◽  
Defect Structure ◽  
Gaas Substrate ◽  
Density Difference ◽  
Interface Plane ◽  
Cross Sectional ◽  
Fringe Contrast ◽  
Gaas Buffer Layer

ABSTRACTThe defect structure in a GaP/GaAs/GaP heterostructure deposited on a (001) GaAs substrate with a GaAs buffer layer has been characterized by cross sectional TEM. The buffer layer presents dislocations and (α-δ)-fringe contrast parallel to (001) interface plane. HREM study reveals uniformly distributed amorphous capsules in the first GaP/GaAs buffer layer interface. The dominant defects are microtwins which are propagated into the overall heterostructure. Microtwin density is different in the GaP and GaAs layers.The different stress signs may explain the density difference.

The Formation and Cathodoluminescence Activity of Buffer Layer Edge Dislocations in In0.12Ga0.88As/GaAs Heterostructures

1987 ◽  
Vol 104 ◽  
Author(s):  
E. A. Fitzgerald ◽  
P. D. Kirchner ◽  
G. D. Petit ◽  
J. M. Woodall ◽  
D. G. Ast
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Buffer Layer ◽  
Defect Structure ◽  
Radiative Recombination ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Gaas Buffer Layer ◽  
Edge Dislocations

ABSTRACTThe defect structure of lattice-mismatched one micron In0.12 Ga0.88As epilayers on (001) GaAs was studied with scanning cathodoluminescence (CL) and transmission electron microscopy (TEM). CL examination of the GaAs buffer layer revealed the formation of a segmented network of defects below the interface. Cross-sectional TEM analysis shows that these defects are dislocation half-loops extending from the interface, and the vast majority of these loops lie on the GaAs side of the interface. The dislocations in the GaAs buffer layer were determined to be edge dislocations. Thus, CL images show that edge dislocations in this system are centers for non-radiative recombination. We propose that two 60° dislocations with opposite screw and interface tilt components can glide into the buffer layer to form edge dislocations. Potential energy plots for 60° dislocations near the interface and interacting with interface dislocations supports this model.

Characterization of GaAs buffer layer function in GaAs/InP strained structure grown by MBE

1996 ◽  
Vol 286 (1-2) ◽  
pp. 107-110 ◽  
Author(s):  
Ching-Ting Lee ◽  
Chi-Yu Wang ◽  
Yeong-Chang Chou
Keyword(s):  
Buffer Layer ◽  
Layer Function ◽  
Gaas Buffer Layer

TEM Analysis of Planar Defects in InGaAsN and GaAs Grown on Ge (001) by MOVPE

2016 ◽  
Vol 675-676 ◽  
pp. 639-642
Author(s):  
Pornsiri Wanarattikan ◽  
Sakuntam Sanorpim ◽  
Somyod Denchitcharoen ◽  
Visittapong Yordsri ◽  
Chanchana Thanachayanont ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Buffer Layer ◽  
Growth Direction ◽  
Dark Field ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Planar Defects ◽  
Transmission Electron ◽  
Gaas Buffer Layer ◽  
Field Emission Electron Microscopy

InGaAsN on Ge (001) is proposed to be a part of the InGaP(N)/InGaAs/InGaAsN/Ge four-junction solar cell to increase a conversion efficiency over 40%. In this work, InGaAsN lattice-matched film and GaAs buffer layer grown on Ge (001) substrate by metal organic vapor phase epitaxy (MOVPE) were examined by transmission electron microscopy (TEM). Electron diffraction pattern of InGaAsN taken along the [110]-zone axis illustrates single diffracted spots, which represent a layer with a uniformity of alloy composition. Cross-sectional bright field TEM image showed line contrasts generated at the GaAs/Ge interface and propagated to the InGaAsN layer. Dark field TEM images of the same area showed the presence of boundary-like planar defects lying parallel to the growth direction in the InGaAsN film and GaAs buffer layer but not in the Ge substrate. TEM images with the (002) and (00-2) reflections and the four visible {111} planes reflections illustrated planar defects which are expected to attribute to antiphase boundaries (APBs). Moreover, the results observed from atomic force microscopy (AFM) and field emission electron microscopy (FE-SEM) demonstrated the surface morphology of InGaAsN film with submicron-sized domains, which is a characteristic of the APBs.

Structural characterization of strained silicon grown on a SiGe buffer layer

2008 ◽  
Vol 23 (3) ◽  
pp. 035012 ◽  
Author(s):  
J H Jang ◽  
M S Phen ◽  
A Gerger ◽  
K S Jones ◽  
J L Hansen ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Structural Characterization ◽  
Strained Silicon

A Tem Study of Defect Structure in GaAs Film on Si Substrate

1993 ◽  
Vol 325 ◽  
Author(s):  
Sahn Nahm ◽  
Hee-Tae Lee ◽  
Sang-Gi Kim ◽  
Kyoung-Ik Cho
Keyword(s):  
Buffer Layer ◽  
Defect Structure ◽  
Stacking Faults ◽  
Misfit Dislocations ◽  
Gaas Film ◽  
Si Substrate ◽  
Moiré Fringes ◽  
Gaas Films ◽  
Layer Stacking ◽  
Gaas Buffer Layer

AbstractFor the GaAs buffer layer deposited on Si substrate at 80°C and annealed at 300°C for 10 min, the size of most GaAs islands was observed as ∼ 10 nm but large islands (∼ 40 nm) were also seen. According to the calculation of spacing of moire fringes, large GaAs islands are considered to be rotated about 4 ° with respect to the Si substrate normal. However, for the main GaAs film overgrown on the GaAs buffer layer at 580 °C, moire fringes with the spacing of 5 nm (GaAs film without rotation) completely covered the surface of Si substrate. Misfit dislocations and stacking faults were already formed at the growth stage of buffer layer. Stacking faults and misfit dislocations consisting of Lomer and 60 ° dislocations were observed in GaAs films grown at 580 °C. However, after rapid thermal annealing at 900 °C for 10 sec, only Lomer dislocations with 1/2[110] and 1/2[-110] Burgers vectors were observed.

A structural characterization of the buffer layer for growth of magnetically coupled Co/Cu superlattices

1993 ◽  
Vol 121 (1-3) ◽  
pp. 20-23
Author(s):  
J.L. Martínez-Albertos ◽  
J. Camarero ◽  
J.M. García ◽  
C.J. Pastor ◽  
J.M. Gallego ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Structural Characterization

Photoreflectance Spectra from GaAs Buffer Layer of GaAs/AlAs Multiple Quantum Well/GaAs Buffer/GaAs Substrate

1991 ◽  
Vol 30 (Part 1, No. 7) ◽  
pp. 1367-1372 ◽  
Author(s):  
Masanobu Haraguchi ◽  
Yoshinori Nakagawa ◽  
Masuo Fukui ◽  
Shunichi Muto
Keyword(s):  
Quantum Well ◽  
Buffer Layer ◽  
Gaas Substrate ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Gaas Buffer Layer

Cross‐sectional structural characterization of the surface of exfoliated HOPG using HRTEM‐EELS

2020 ◽  
Vol 53 (1) ◽  
pp. 84-89
Author(s):  
Kun'ichi Miyazawa ◽  
Takuro Nagai ◽  
Koji Kimoto ◽  
Masaru Yoshitake ◽  
Yumi Tanaka
Keyword(s):  
Structural Characterization ◽  
Cross Sectional

scholarly journals Hyperspectral interference tomography of nacre

2021 ◽  
Vol 118 (15) ◽  
pp. e2023623118
Author(s):  
Jad Salman ◽  
Cayla A. Stifler ◽  
Alireza Shahsafi ◽  
Chang-Yu Sun ◽  
Stephen C. Weibel ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Field Studies ◽  
Nondestructive Method ◽  
Organic Polymer ◽  
Cross Sectional ◽  
Haliotis Rufescens ◽  
Mollusk Shells ◽  
Biological Phenomena

Structural characterization of biologically formed materials is essential for understanding biological phenomena and their enviro-nment, and for generating new bio-inspired engineering concepts. For example, nacre—the inner lining of some mollusk shells—encodes local environmental conditions throughout its formation and has exceptional strength due to its nanoscale brick-and-mortar structure. This layered structure, comprising alternating transparent aragonite (CaCO3) tablets and thinner organic polymer layers, also results in stunning interference colors. Existing methods of structural characterization of nacre rely on some form of cross-sectional analysis, such as scanning or transmission electron microscopy or polarization-dependent imaging contrast (PIC) mapping. However, these techniques are destructive and too time- and resource-intensive to analyze large sample areas. Here, we present an all-optical, rapid, and nondestructive imaging technique—hyperspectral interference tomography (HIT)—to spatially map the structural parameters of nacre and other disordered layered materials. We combined hyperspectral imaging with optical-interference modeling to infer the mean tablet thickness and its disorder in nacre across entire mollusk shells from red and rainbow abalone (Haliotis rufescens and Haliotis iris) at various stages of development. We observed that in red abalone, unexpectedly, nacre tablet thickness decreases with age of the mollusk, despite roughly similar appearance of nacre at all ages and positions in the shell. Our rapid, inexpensive, and nondestructive method can be readily applied to in-field studies.

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