Controlling (In, Ga)As quantum structures on high index GaAs surfaces

2004 ◽  
Vol 854 ◽  
Author(s):  
Sh. Seydmohamadi ◽  
H. Wen ◽  
Zh. M. Wang ◽  
G. J. Salamo
Keyword(s):  
Quantum Wires ◽  
High Energy ◽  
High Index ◽  
Quantum Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Stereographic Triangle ◽  
Atomic Force

ABSTRACTWe investigate the formation of (In, Ga)As self assembled quantum structures grown on different orientations of a GaAs substrate along one side of the stereographic triangle between (100) and (111)A surfaces. The samples were grown by Molecular Beam Epitaxy, monitored by Reflection High-Energy Electron Diffraction during the growth and characterized by in-situ Scanning Tunneling Microscopy and Atomic Force Microscopy. A systematic transition from zero dimensional (In, Ga)As quantum dots to one dimensional quantum wires was observed as the substrate was varied along the side of the triangle within 25° miscut from the (100) toward (111)A, which includes several high index surfaces. We propose an explanation for the role of the substrate in determining the type of the nanostructure that is formed.

Controlling (In, Ga)As quantum structures on high index GaAs surfaces

2004 ◽  
Vol 849 ◽  
Author(s):  
Sh. Seydmohamadi ◽  
H. Wen ◽  
Zh. M. Wang ◽  
G. J. Salamo
Keyword(s):  
Quantum Wires ◽  
High Energy ◽  
High Index ◽  
Quantum Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Stereographic Triangle ◽  
Atomic Force

AbstractWe investigate the formation of (In, Ga)As self assembled quantum structures grown on different orientations of a GaAs substrate along one side of the stereographic triangle between (100) and (111)A surfaces. The samples were grown by Molecular Beam Epitaxy, monitored by Reflection High-Energy Electron Diffraction during the growth and characterized by in-situ Scanning Tunneling Microscopy and Atomic Force Microscopy. A systematic transition from zero dimensional (In, Ga)As quantum dots to one dimensional quantum wires was observed as the substrate was varied along the side of the triangle within 25° miscut from the (100) toward (111)A, which includes several high index surfaces. We propose an explanation for the role of the substrate in determining the type of the nanostructure that is formed.

Controlling (In,Ga)As quantum structures on high index GaAs surfaces

2004 ◽  
Vol 859 ◽  
Author(s):  
Sh. Seydmohamadi ◽  
H. Wen ◽  
Zh. M. Wang ◽  
G. J. Salamo
Keyword(s):  
Quantum Wires ◽  
High Energy ◽  
High Index ◽  
Quantum Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Stereographic Triangle ◽  
Atomic Force

ABSTRACTWe investigate the formation of (In, Ga) As self assembled quantum structures grown on different orientations of a GaAs substrate along one side of the stereographic triangle between (100) and (111)A surfaces. The samples were grown by Molecular Beam Epitaxy, monitored by Reflection High-Energy Electron Diffraction during the growth and characterized by in-situ Scanning Tunneling Microscopy and Atomic Force Microscopy. A systematic transition from zero dimensional (In, Ga) As quantum dots to one dimensional quantum wires was observed as the substrate was varied along the side of the triangle within 25° miscut from the (100) toward (111)A, which includes several high index surfaces. We propose an explanation for the role of the substrate in determining the type of the nanostructure that is formed.

Nanometer-sized tungsten tips for STM and AFM

1991 ◽  
Vol 49 ◽  
pp. 386-387
Author(s):  
Mircea Fotino
Keyword(s):  
Surface Structures ◽  
Three Dimensions ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Mechanical Grinding ◽  
Tunneling Microscopy ◽  
Essential Requirement ◽  
Force Microscopy ◽  
Atomic Force

An essential requirement in the pursuit of atomic resolution by scanning tunneling microscopy (STM) or atomic force microscopy (AFM) is the use of a tip with an apex of dimensions comparable to or preferably smaller than those of the specimen to be identified. Although atomic resolution of mostly planar specimens has been obtained even with atomically blunt tips, the above requirement appears indispensable for determining 3D surface structures extending equally in all three dimensions.Tips most commonly used so far in STM or AFM applications are made by grinding or by etching a thin and rigid Pt/Ir or W wire. Mechanical grinding occasionally leaves protruding spikes typically several tens of nm in radius that can play the role of scanning stilus even though neither adequately oriented nor particularly sharp and symmetric.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

scholarly journals Exploring Intramolecular Methyl–Methyl Coupling on a Metal Surface for Edge-Extended Graphene Nanoribbons

2021 ◽  
Vol 03 (02) ◽  
pp. 128-133
Author(s):  
Zijie Qiu ◽  
Qiang Sun ◽  
Shiyong Wang ◽  
Gabriela Borin Barin ◽  
Bastian Dumslaff ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Atomic Force Microscopy ◽  
High Resolution ◽  
Graphene Nanoribbons ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Methyl Methyl ◽  
Atomic Force ◽  
Edge Extension

Intramolecular methyl–methyl coupling on Au (111) is explored as a new on-surface protocol for edge extension in graphene nanoribbons (GNRs). Characterized by high-resolution scanning tunneling microscopy, noncontact atomic force microscopy, and Raman spectroscopy, the methyl–methyl coupling is proven to indeed proceed at the armchair edges of the GNRs, forming six-membered rings with sp3- or sp2-hybridized carbons.

SCANNING PROBE MICROSCOPY BASED NANOSCALE PATTERNING AND FABRICATION

COSMOS ◽  
2007 ◽  
Vol 03 (01) ◽  
pp. 1-21 ◽  
Author(s):  
XIAN NING XIE ◽  
HONG JING CHUNG ◽  
ANDREW THYE SHEN WEE
Keyword(s):  
Integrated Circuits ◽  
Scanning Probe Microscopy ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Nanoscale Patterning ◽  
Atomic Force ◽  
Probe Microscope ◽  
Molecular Manipulation

Nanotechnology is vital to the fabrication of integrated circuits, memory devices, display units, biochips and biosensors. Scanning probe microscope (SPM) has emerged to be a unique tool for materials structuring and patterning with atomic and molecular resolution. SPM includes scanning tunneling microscopy (STM) and atomic force microscopy (AFM). In this chapter, we selectively discuss the atomic and molecular manipulation capabilities of STM nanolithography. As for AFM nanolithography, we focus on those nanopatterning techniques involving water and/or air when operated in ambient. The typical methods, mechanisms and applications of selected SPM nanolithographic techniques in nanoscale structuring and fabrication are reviewed.

Micromechanisms of Hydrogen-Assisted Cracking in Super Duplex Stainless Steel Investigated by Scanning Probe Microscopy

2014 ◽  
Author(s):  
Bai An ◽  
Takashi Iijima ◽  
Chris San Marchi ◽  
Brian Somerday
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Scanning Tunneling ◽  
Super Duplex Stainless Steel ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hydrogen Assisted Cracking ◽  
Cracking Mechanisms ◽  
Localized Plastic Deformation

Understanding the micromechanisms of hydrogen-assisted fracture in multiphase metals is of great scientific and engineering importance. By using a combination of scanning electron microscopy (SEM), scanning tunneling microscopy (STM), atomic force microscopy (AFM) and magnetic force microscopy (MFM), the micromorphology of fracture surface and microcrack formation in hydrogen-precharged super duplex stainless steel 2507 are characterized from microscale to nanoscale. The results reveal that the fracture surfaces consist of quasi-brittle facets with riverlike patterns at the microscale, which exhibit rough irregular patterns or remarkable quasi-periodic corrugation patterns at the nanoscale that can be correlated with highly localized plastic deformation. The microcracks preferentially initiate and propagate in ferrite phase and are stopped or deflected by the boundaries of the austenite phase. The hydrogen-assisted cracking mechanisms in super duplex stainless steel are discussed according to the experimental results and hydrogen-enhanced localized plasticity theory.

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