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.

scholarly journals Atomic Resolution with the Atomic Force Microscope

1995 ◽  
Vol 3 (4) ◽  
pp. 6-7
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Atomic Force Microscopy ◽  
Scanning Tunneling Microscopy ◽  
Atomic Force Microscope ◽  
Recent Article ◽  
Atomic Scale ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force

For biologic studies, atomic force microscopy (AFM) has been prevailing over scanning tunneling microscopy (STM) because it has the capability of imaging non-conducting biologic specimens. However, STM generally gives better resolution than AFM, and we're talking about resolution on the atomic scale. In a recent article, Franz Giessibl (Atomic resolution of the silicon (111)- (7X7) surface by atomic force microscopy, Science 267:68-71, 1995) has demonstrated that atoms can be imaged by AFM.

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.

Resolution Issues in Scanned Probe Microscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 1187-1188
Author(s):  
P. E. Russell
Keyword(s):  
Scanning Force Microscopy ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Probe Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sample Height ◽  
Scanned Probe Microscopy ◽  
Scanning Force

Scanned Probe Microscopy first received widespread recognition in the form of scanning tunneling microscopy (STM) images clearly showing atomic resolution of the Si 111 surface in the characteristic 7×7 surface reconstruction. For this sample, STM imaging under carefully controlled ultrahigh vacuum conditions reveals the clear image of each atom position within the surface unit cell with excellent contrast and clearly atomic resolution. Over the past few years, versions of scanning force microscopy (commonly referred to as atomic force microscopy or AFM) have become much more widespread than STM. A very common, and very difficult question, is: What is the resolution of AFM? The simple answer is that SPM in general, and STM and AFM in particular, routinely obtain sub-angstrom resolution—in the z axis, or the sample height direction. This high resolution capability is easily demonstrated by scanning a cleaved crystal of known lattice spacing and observing single and multiple atomic steps.

scholarly journals Mapping Dielectric Properties with Torsionally Stabilized Nano Impedance Microscopy: Hard Materials to Biomolecules

2011 ◽  
Vol 19 (6) ◽  
pp. 16-20 ◽  
Author(s):  
Kendra Kathan-Galipeau ◽  
Xi Chen ◽  
Bohdana Discher ◽  
Dawn A. Bonnell
Keyword(s):  
Significant Contribution ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Hard Materials ◽  
Insulating Surfaces ◽  
Atomic Force ◽  
Wide Range ◽  
Local Properties

During the last twenty-five years of scanning tunneling microscopy (STM), atomic resolution has become routine in studies of a wide range of materials. While less routine, atomic force microscopy (AFM) also can achieve atomic resolution, even on insulating surfaces. These two microscopy approaches have significantly advanced our understanding of the surface physics and chemistry of many important phenomena. A significant contribution of scanning probe microscopy is that it can characterize local properties as well as structure. Surprising levels of spatial resolution have been achieved in scanning probes that can access continuum properties such as resistance, capacitance, etc..

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.

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