Effects of Discrete Protein-Surface Interactions in Scanning Force Microscopy Adhesion Force Measurements

Monolithic integration of optoelectronic integrated circuits (OEIC) requires high quantity etched laser facets which prevent the developing of more-highly-integrated OEIC's. The causes of facet roughness are not well understood, and improvement of facet quality is hampered by the difficulty in measuring the surface roughness. There are several approaches to examining facet roughness qualitatively, such as scanning force microscopy (SFM), scanning tunneling microscopy (STM) and scanning electron microscopy (SEM). The challenge here is to allow more straightforward monitoring of deep vertical etched facets, without the need to cleave out test samples. In this presentation, we show air based STM and SFM images of vertical dry-etched laser facets, and discuss the image acquisition and roughness measurement processes. Our technique does not require precision cleaving. We use a traditional tip instead of the T shape tip used elsewhere to preventing “shower curtain” profiling of the sidewall. We tilt the sample about 30 to 50 degrees to avoid the curtain effect.

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Log-log scale roughness spectroscopy of surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146965 ◽

1993 ◽

Vol 51 ◽

pp. 224-225

Author(s):

P. Fraundorf ◽

B. Armbruster

Keyword(s):

Power Spectrum ◽

Autocorrelation Function ◽

Power Spectra ◽

Scanning Force Microscopy ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Force Microscopy ◽

Scanning Force ◽

Lateral Structure ◽

Scale Roughness

Optical interferometry, confocal light microscopy, stereopair scanning electron microscopy, scanning tunneling microscopy, and scanning force microscopy, can produce topographic images of surfaces on size scales reaching from centimeters to Angstroms. Second moment (height variance) statistics of surface topography can be very helpful in quantifying “visually suggested” differences from one surface to the next. The two most common methods for displaying this information are the Fourier power spectrum and its direct space transform, the autocorrelation function or interferogram. Unfortunately, for a surface exhibiting lateral structure over several orders of magnitude in size, both the power spectrum and the autocorrelation function will find most of the information they contain pressed into the plot’s origin. This suggests that we plot power in units of LOG(frequency)≡-LOG(period), but rather than add this logarithmic constraint as another element of abstraction to the analysis of power spectra, we further recommend a shift in paradigm.

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Anisotropy of Nanoindentation – a tool for the determination of nanocrystal orientation ?

MRS Proceedings ◽

10.1557/proc-779-w5.14 ◽

2003 ◽

Vol 779 ◽

Author(s):

David Christopher ◽

Steven Kenny ◽

Roger Smith ◽

Asta Richter ◽

Bodo Wolf ◽

...

Keyword(s):

Crystal Surface ◽

Scanning Force Microscopy ◽

Depth Range ◽

Dislocation Loops ◽

Force Microscopy ◽

Pile Up ◽

Out Of Plane ◽

Scanning Force ◽

Dynamics Simulations

AbstractThe pile up patterns arising in nanoindentation are shown to be indicative of the sample crystal symmetry. To explain and interpret these patterns, complementary molecular dynamics simulations and experiments have been performed to determine the atomistic mechanisms of the nanoindentation process in single crystal Fe{110}. The simulations show that dislocation loops start from the tip and end on the crystal surface propagating outwards along the four in-plane <111> directions. These loops carry material away from the indenter and form bumps on the surface along these directions separated from the piled-up material around the indenter hole. Atoms also move in the two out-of-plane <111> directions causing propagation of subsurface defects and pile-up around the hole. This finding is confirmed by scanning force microscopy mapping of the imprint, the piling-up pattern proving a suitable indicator of the surface crystallography. Experimental force-depth curves over the depth range of a few nanometers do not appear smooth and show distinct pop-ins. On the sub-nanometer scale these pop-ins are also visible in the simulation curves and occur as a result of the initiation of the dislocation loops from the tip.

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Structural and Spectroscopic Study of Langmuir-Schäfer Films of Bis Zn-Ethane-Bridged Porphyrins Dimer

MRS Proceedings ◽

10.1557/proc-771-l7.29 ◽

2003 ◽

Vol 771 ◽

Author(s):

G. Panzera ◽

S. Conoci ◽

S. Coffa ◽

B. Pignataro ◽

S. Sortino ◽

...

Keyword(s):

Surface Pressure ◽

Scanning Force Microscopy ◽

Structural Features ◽

Solid Surfaces ◽

Condensed Phases ◽

Brewster Angle Microscopy ◽

Force Microscopy ◽

Vis Spectroscopy ◽

Scanning Force ◽

Supramolecular Aggregates

AbstractThin films (1-24 layers) of bis-zinc ethane-bridged porphyrin dimer (1) have been transferred on solid surfaces, by the Langmuir- Schäfer (LS) horizontal method. The related surface pressurearea isotherm curve shows that in dependence of the film pressure different condensed phases may occur in the monolayer. The inspection of the monolayer by Brewster Angle Microscopy (BAM) reveals the presence of peculiar networks whose structural features seemingly change upon film compression. On the other hand, the Scanning Force Microscopy (SFM) analysis performed on LS films shows fractal networks constituted by nanoscopic supramolecular aggregates, whose shape and size depend again on the LS deposition surface pressure. Finally, also UV-vis spectroscopy measurements indicates that the absorption is almost linearly related to the film thickness that is directly connected to the surface pressure.

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Photoelectric Response of Self Assembled Films of Bacterio-Rhodopsin Purple Membrane Integrated on Silicon

MRS Proceedings ◽

10.1557/proc-774-o5.4 ◽

2003 ◽

Vol 774 ◽

Author(s):

D. Ricceri ◽

G. Scicolone ◽

O. Di Marco ◽

S. Conoci ◽

B. Pignataro ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Light Exposure ◽

Scanning Force Microscopy ◽

Purple Membrane ◽

Morphological Properties ◽

Force Microscopy ◽

Scanning Force ◽

Scanning Electron ◽

Tungsten Lamp

AbstractBacterio-rhodopsin purple membrane (PM) thin films have been prepared by selfassembling (SA) technique. Morphological properties of the layers were inspected by Scanning Electron Microscopy (SEM) and Scanning Force Microscopy (SFM) highlighting the presence of densely packed PM films. Reflectance Uv-vis spectra on these films revealed the typical bR absorption at 570 nm. By using a tungsten lamp illuminations (250-350 mW) chopped at 0.5Hz, photoelectric responses were detected. Differential (light-on and light-off) photocurrent signals of up to 1 μA/cm2 were obtained upon light exposure.

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