Estimation of Surface Diffusion Length from AFM Images of Faceted GaAs(111) Homoepitaxial Films

1992 ◽  
Vol 280 ◽  
Author(s):  
K. Yang ◽  
L. J. Schowalter ◽  
T. G. Thundat
Keyword(s):  
Atomic Force Microscope ◽  
Surface Diffusion ◽  
Growth Condition ◽  
Diffusion Length ◽  
Vicinal Surfaces ◽  
Average Displacement ◽  
Atomic Force ◽  
Gaas Films

ABSTRACTGaAs films grown on exact (111) substrates in the reconstruction regime always show facets. We have studied the surfaces of these films with an atomic force microscope. The facets are composed of vicinal surfaces which are tilted by small angles (∼ 2°) from the exact (111) plane. From the geometry of the facet, average displacement of adatoms is calculated. The results indicate that the diffusion length under the growth condition is more than 0.2 μm.

A study of surface diffusion on gold with an atomic force microscope

1995 ◽  
Vol 331-333 ◽  
pp. 885-890 ◽  
Author(s):  
H. Göbel ◽  
P. von Blanckenhagen
Keyword(s):  
Atomic Force Microscope ◽  
Surface Diffusion ◽  
Atomic Force

Films Grown on Vicinal GaAs(111) Substrates By Molecular Beam Epitaxy

1992 ◽  
Vol 263 ◽  
Author(s):  
K. Yang ◽  
L. J. Schowalter
Keyword(s):  
Molecular Beam Epitaxy ◽  
Surface Morphology ◽  
Atomic Force Microscope ◽  
Surface Reconstruction ◽  
Molecular Beam ◽  
Vicinal Surfaces ◽  
Atomic Force ◽  
Morphology Of Films ◽  
Surface Morphologies

ABSTRACTThe faceted surface morphology of films grown on on-axis GaAs(111) substrates in the reconstruction regime is studied with an atomic force microscope. It reveals that facets are vicinal surfaces. Surface morphologies of films grown on substrates tilted toward different directions have been compared. An explanation is given for all observed surface morphologies. Smooth films can only be obtained on substrates tilted toward [211] in the surface reconstruction regime.

Characterization of photosystem II with the atomic-force microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1146-1147
Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon
Keyword(s):  
Photosystem Ii ◽  
Atomic Force Microscope ◽  
Three Dimensional ◽  
Biologically Active ◽  
Atomic Force ◽  
Freeze Etching ◽  
Image Averaging ◽  
Oxygen Evolving ◽  
Averaging Techniques

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

The atomic-force microscope and its future in biology

1993 ◽  
Vol 51 ◽  
pp. 704-705
Author(s):  
Jean-Paul Revel
Keyword(s):  
Silicon Nitride ◽  
Laser Beam ◽  
Atomic Force Microscope ◽  
Scanning Tunneling Microscope ◽  
Point Of View ◽  
Scanning Tunneling ◽  
Close Relative ◽  
Tunneling Microscope ◽  
Atomic Force ◽  
Sharp Point

The last few years have been marked by a series of remarkable developments in microscopy. Perhaps the most amazing of these is the growth of microscopies which use devices where the place of the lens has been taken by probes, which record information about the sample and display it in a spatial from the point of view of the context. From the point of view of the biologist one of the most promising of these microscopies without lenses is the scanned force microscope, aka atomic force microscope.This instrument was invented by Binnig, Quate and Gerber and is a close relative of the scanning tunneling microscope. Today's AFMs consist of a cantilever which bears a sharp point at its end. Often this is a silicon nitride pyramid, but there are many variations, the object of which is to make the tip sharper. A laser beam is directed at the back of the cantilever and is reflected into a split, or quadrant photodiode.

The application of atomic force microscope in microbiological research

2014 ◽  
Vol 5 (1) ◽  
pp. 27-30
Author(s):  
Małgorzata Tokarska-Rodak ◽  
Maria Kozioł-Montewka ◽  
Jolanta Paluch-Oleś ◽  
Dorota Plewik ◽  
Grażyna Olchowik ◽  
...  
Keyword(s):  
Atomic Force Microscope ◽  
Atomic Force ◽  
Microbiological Research

Failure Analysis of Laser Blown Metal Fuse Failures in Submicron Technology by C-AFM

2006 ◽  
Author(s):  
Liang-Feng Wen ◽  
Chien-Hui Chen ◽  
Allen Timothy Chang
Keyword(s):  
Failure Analysis ◽  
Atomic Force Microscope ◽  
Laser Cutting ◽  
Spot Size ◽  
Repair Rate ◽  
Atomic Force ◽  
Measurement Laser

Abstract This paper presents a method of using a conductive atomic force microscope (C-AFM) to characterize a submicron metal fuse that has been blown open inadequately by laser. In order to obtain a proper I-V curve measured using the C-AFM without affecting the incompletely opened fuse, the paper proposes a method of preserving the fuse by coating its surface with spin-on glass. The paper explains how differences in laser cutting machines resulted in the high failure repair rate of customer product despite equivalent energy and spot size settings. Analysis of the fuse bank circuitry on wafers helped to find the critical physical differences between a fully blown and a poorly blown fuse. By overcoming difficulties in preserving the blown fuse failure sites for C-AFM measurement, laser settings could be easily optimized to ensure proper fuse opening.

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