Scanning force microscopy observation of GaAs and AlGaAs surfaces grown by molecular beam epitaxy

1992 ◽  
Vol 71 (1) ◽  
pp. 158-163 ◽  
Author(s):  
Yoon Soon Fatt
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Scanning Force Microscopy ◽  
Microscopy Observation ◽  
Force Microscopy ◽  
Scanning Force

Evolution of Roughness on InP Layers Observed by Scanning Force Microscopy

1993 ◽  
Vol 312 ◽  
Author(s):  
M. A Cotta ◽  
R. A Hamm ◽  
S. N. G Chu ◽  
T. W Staley ◽  
L. R Harriott ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Scanning Force Microscopy ◽  
Two Dimensional ◽  
Group Iii ◽  
Force Microscopy ◽  
Metalorganic Molecular Beam Epitaxy ◽  
Scanning Force ◽  
Dimensional Growth

AbstractThe evolution of surface roughness with increasing thickness of (100) InP layersgrown by metalorganic molecular beam epitaxy has been observed by scanningforce microscopy. The process of roughening gives rise to periodic elongatedfeatures on the surface aligned in the [011] direction, reflecting the surfaceanisotropy. The morphology eventually evolves to a grain-like surface. Theroughening is dependent on both the group III and V flux, and the growthtemperature, indicating that this phenomenon is kinetically controlled by surfacediffusion activation. For each set of parameters chosen for the growth, there is aminimum temperature where smooth, two-dimensional growth can be obtained.Below that temperature the roughening shows two distinct power law regimesdependent on the epitaxial layer thickness.

Scanned tip measurement of deep vertical facets on a flat surface: Measuring roughness on gaas laser waveguide mirrors

1993 ◽  
Vol 51 ◽  
pp. 532-533
Author(s):  
Chang Shen ◽  
Phil Fraundorf ◽  
Robert W. Harrick
Keyword(s):  
Integrated Circuits ◽  
Flat Surface ◽  
Scanning Force Microscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Optoelectronic Integrated Circuits ◽  
Laser Waveguide ◽  
Scanning Force ◽  
Gaas Laser

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.

Log-log scale roughness spectroscopy of surfaces

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.

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

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.

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

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.

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

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.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

Sign in / Sign up

Export Citation Format

Share Document