Atiomiic Scale Interface Structure of In0.2Ga0.8As/GaAs Strained Layers Studied by Crosssectional Scanning Tunneijng Microscopy

1993 ◽  
Vol 319 ◽  
Author(s):  
J. F. Zheng ◽  
M. B. Salmeron ◽  
E. R. Weber
Keyword(s):  
Molecular Beam ◽  
Layer Structure ◽  
Growth Direction ◽  
Interface Roughness ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Strained Layers ◽  
Group Iii ◽  
Scale Fluctuation

AbstractA molecular beam epitaxy-grown In0.2Ga0.8As/GaAs strained layer structure has been studied by scanning tunneling microscopy in cross-section on the (110) cleavage plane perpendicular to [001] the growth direction. Individual Indium atoms were differentially imaged in the group III sublattice, allowing a direct observation of the interface roughness due to the indium compositional fluctuation. In the In0.2Ga0.8As layers, Indium atoms are found in clusters preferentially along the growth direction with each cluster containing 2-3 indium atoms. Indium segregation induced asymmetrical interface broadening is studied on an atomic scale. The interface of In0.2Ga0.8As grown on GaAs is sharp within 2-4 atomic layers. The interface of GaAs grown on In0.2Ga0.8As is found to be broadened to about 5-10 atomic layers. The atomic scale fluctuation due to indium distribution is about 20 Å along the interface in this case. We conclude that clustering and segregation are the main reason for the In0.2Ga0.8As/GaAs interface roughness.

Anisotropy in Atomic-Scale Interface Structure and Mobility in Inas/Ga1_Xinxsb Superlattices

1996 ◽  
Vol 448 ◽  
Author(s):  
A. Y. Lew ◽  
S. L. Zuo ◽  
E. T. Yu ◽  
R. H. Miles
Keyword(s):  
Quantitative Analysis ◽  
Molecular Beam ◽  
Interface Structure ◽  
Interface Roughness ◽  
Atomic Scale ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Interfacial Bond ◽  
Tunneling Microscopy ◽  
Cross Sectional

AbstractWe have used cross-sectional scanning tunneling microscopy to study the atomic-scale interface structure of InAs/Ga, _In.xSb superlattices grown by molecular-beam epitaxy. Detailed, quantitative analysis of interface profiles obtained from constant-current images of both (110) and (1ī0) cross-sectional planes of the superlattice indicates that interfaces in the (1ī0) plane exhibit a higher degree of interface roughness than those in the (110) plane, and that the Ga1-xln xAs interfaces are rougher than the InAs-on-Gal1-xInxSb interfaces. The roughness data are consistent with anisotropy in interface structure arising from anisotropic island formation during growth, and in addition with a growth-sequence-dependent interface asymmetry resulting from differences in interfacial bond structure between the superlattice layers. Roughness data are compared with measurements of anisotropy in low-temperature Hall mobilities of the samples.

scholarly journals Scanning Tunneling Microscopy Studies of InGaN Growth by Molecular Beam Epitaxy

1999 ◽  
Vol 4 (S1) ◽  
pp. 858-863
Author(s):  
Huajie Chen ◽  
A. R. Smith ◽  
R. M. Feenstra ◽  
D. W. Greve ◽  
J. E. Northrup
Keyword(s):  
Molecular Beam Epitaxy ◽  
Scanning Tunneling Microscopy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Growth Parameters ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Group V ◽  
Group Iii ◽  
Ingan Alloys

InGaN alloys with indium compositions ranging from 0–40% have been grown by molecular beam epitaxy. The dependence of the indium incorporation on growth temperature and group III/group V ratio has been studied. Scanning tunneling microscopy images, interpreted using first-principles theoretical computations, show that there is strong indium surface segregation on InGaN. Based on this surface segregation, a qualitative model is proposed to explain the observed indium incorporation dependence on the growth parameters.

scholarly journals Indium incorporation and surface segregation during InGaN growth by molecular beam epitaxy: experiment and theory

2001 ◽  
Vol 6 ◽  
Author(s):  
Huajie Chen ◽  
R. M. Feenstra ◽  
J. E. Northrup ◽  
Jörg Neugebauer ◽  
D.W. Greve
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Theoretical Calculations ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Group Iii ◽  
Existence And Stability ◽  
Image Position ◽  
Ingan Alloys

InGaN alloys with (0001) or (000) polarities are grown by plasma-assisted molecular beam epitaxy. Scanning tunneling microscopy images, interpreted using first-principles theoretical calculations, show that there is strong indium surface segregation on InGaN for both (0001) and (000) polarities. Evidence for the existence and stability of a structure containing two adlayers of indium on the In-rich InGaN(0001) surface is presented. The dependence on growth temperature and group III/V ratio of indium incorporation in InGaN is reported, and a model based on indium surface segregation is proposed to explain the observations.

Quenching Effects in Scanning Tunneling Microscopy Studies of Epitaxial Growth

1999 ◽  
Vol 583 ◽  
Author(s):  
G. R. Bell
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Molecular Beam Epitaxial ◽  
Rapid Quench ◽  
Molecular Beam Epitaxial Growth

AbstractThe experimental aspects of rapid-quench scanning tunneling microscopy are discussed. In particular, the effects of sample quenching are investigated in atomic-scale studies of the molecular beam epitaxial growth of GaAs. Implications for the study of the heteroepitaxial system InAs-GaAs are discussed.

Indium incorporation and surface segregation during InGaN growth by molecular beam epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Huajie Chen ◽  
R. M. Feenstra ◽  
J. E. Northrup ◽  
J. Neugebauer ◽  
D. W. Greve
Keyword(s):  
Molecular Beam Epitaxy ◽  
Growth Temperature ◽  
First Principles ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Group Iii ◽  
Microscopy Images ◽  
Ingan Alloys

ABSTRACTInGaN alloys with (0001) or (000) polarities are grown by plasma-assisted molecular beam epitaxy. Scanning tunneling microscopy images, interpreted using first-principles theoretical cal- culations, show that there is strong indium surface segregation on InGaN for both (0001) and (000) polarities. The dependence on growth temperature and group III/V ratio of indium incorporation in InGaN is reported, and a model based on indium surface segregation is proposed to ex- plain the observations.

Scanning Tunneling Microscopy Studies of InGaN Growth by Molecular Beam Epitaxy

1998 ◽  
Vol 537 ◽  
Author(s):  
Huajie Chen ◽  
A. R. Smith ◽  
R. M. Feenstra ◽  
D. W. Greve ◽  
J. E. Northrup
Keyword(s):  
Molecular Beam Epitaxy ◽  
Scanning Tunneling Microscopy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Growth Parameters ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Group V ◽  
Group Iii ◽  
Ingan Alloys

AbstractInGaN alloys with indium compositions ranging from 0–40% have been grown by molecular beam epitaxy. The dependence of the indium incorporation on growth temperature and group III/group V ratio has been studied. Scanning tunneling microscopy images, interpreted using first-principles theoretical computations, show that there is strong indium surface segregation on InGaN. Based on this surface segregation, a qualitative model is proposed to explain the observed indium incorporation dependence on the growth parameters.

STM studies of crystal growth

1991 ◽  
Vol 49 ◽  
pp. 374-375
Author(s):  
M. G. Lagally
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Sputter Deposition ◽  
Field Of View ◽  
Scanning Tunneling ◽  
Wide Field ◽  
Tunneling Microscopy ◽  
Wide Field Of View ◽  
The One

It has been recognized since the earliest days of crystal growth that kinetic processes of all Kinds control the nature of the growth. As the technology of crystal growth has become ever more refined, with the advent of such atomistic processes as molecular beam epitaxy, chemical vapor deposition, sputter deposition, and plasma enhanced techniques for the creation of “crystals” as little as one or a few atomic layers thick, multilayer structures, and novel materials combinations, the need to understand the mechanisms controlling the growth process is becoming more critical. Unfortunately, available techniques have not lent themselves well to obtaining a truly microscopic picture of such processes. Because of its atomic resolution on the one hand, and the achievable wide field of view on the other (of the order of micrometers) scanning tunneling microscopy (STM) gives us this opportunity. In this talk, we briefly review the types of growth kinetics measurements that can be made using STM. The use of STM for studies of kinetics is one of the more recent applications of what is itself still a very young field.

Resolution in the scanning tunneling microscope

1991 ◽  
Vol 49 ◽  
pp. 488-489
Author(s):  
R. J. Wilson ◽  
D. D. Chambliss ◽  
S. Chiang ◽  
V. M. Hallmark
Keyword(s):  
Scanning Tunneling Microscope ◽  
Fundamental Principle ◽  
Atomic Scale ◽  
Lateral Resolution ◽  
Scanning Tunneling ◽  
Electronic Noise ◽  
Vertical Resolution ◽  
Tunneling Microscopy ◽  
Spatial Profile ◽  
Theoretical Analyses

Scanning tunneling microscopy (STM) has been used for many atomic scale observations of metal and semiconductor surfaces. The fundamental principle of the microscope involves the tunneling of evanescent electrons through a 10Å gap between a sharp tip and a reasonably conductive sample at energies in the eV range. Lateral and vertical resolution are used to define the minimum detectable width and height of observed features. Theoretical analyses first discussed lateral resolution in idealized cases, and recent work includes more general considerations. In all cases it is concluded that lateral resolution in STM depends upon the spatial profile of electronic states of both the sample and tip at energies near the Fermi level. Vertical resolution is typically limited by mechanical and electronic noise.

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