Atomic Scale Characterization of (NH4)2Sx-Treated GaAs (100) Surface

1994 ◽  
Vol 332 ◽  
Author(s):  
Naoki Yokoi ◽  
Hiroya Andoh ◽  
Mikio Takai
Keyword(s):  
Surface Region ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Ion Scattering ◽  
Tunneling Microscopy ◽  
Xps Spectra ◽  
Sulfur Layer ◽  
Scale Characterization ◽  
Medium Energy Ion Scattering

ABSTRACTThe geometric structure of GaAs (100) surfaces, treated in a (NH4)2Sx solution and annealed in N2 environment, has been studied in an atomic scale using high-resolution Rutherford backscattering (RBS), X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). RBS analysis using medium energy ion scattering (MEIS) could provide the thickness of the sulfur layer on the GaAs surface of about 1.5 monolayers. RBS channeling spectra indicated that the disorder of atoms in the surface region of S-terminated samples was smaller than that of untreated one. XPS spectra showed that S atoms on the surface bonded only As atoms. STM observation revealed that S atoms had a periodicity of 4 Å corresponding to that of Ga or As atoms in the (100) plane.

Atomic-scale Characterization of HF-treated 4H-SiC(0001)1×1 Surfaces by Scanning Tunneling Microscopy

2007 ◽  
Vol 996 ◽  
Author(s):  
Kenta Arima ◽  
Hideyuki Hara ◽  
Yasuhisa Sano ◽  
Keita Yagi ◽  
Ryota Okamoto ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Chemical Preparation ◽  
Local Structures ◽  
Wet Chemical ◽  
Low Energy Electron ◽  
Scale Characterization

AbstractScanning tunneling microscopy (STM) observations are performed on 4H-SiC(0001) surfaces after wet-chemical preparation steps including HF treatments.1×1 structures are formed on a terrace together with other local structures. Their atomic images are investigated in conjunction with low-energy electron diffraction and electron spectroscopy for chemical analysis. It is suggested that each bright dot forming the 1×1 phase corresponds to an OH-terminated Si atom.

scholarly journals Atomic-Scale Characterization of Droplet Epitaxy Quantum Dots

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 85
Author(s):  
Raja S. R. Gajjela ◽  
Paul M. Koenraad
Keyword(s):  
Quantum Dots ◽  
Optoelectronic Devices ◽  
Atomic Scale ◽  
Droplet Epitaxy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Etch Pits ◽  
Cross Sectional ◽  
Scale Characterization

The fundamental understanding of quantum dot (QD) growth mechanism is essential to improve QD based optoelectronic devices. The size, shape, composition, and density of the QDs strongly influence the optoelectronic properties of the QDs. In this article, we present a detailed review on atomic-scale characterization of droplet epitaxy quantum dots by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). We will discuss both strain-free GaAs/AlGaAs QDs and strained InAs/InP QDs grown by droplet epitaxy. The effects of various growth conditions on morphology and composition are presented. The efficiency of methods such as flushing technique is shown by comparing with conventional droplet epitaxy QDs to further gain control over QD height. A detailed characterization of etch pits in both QD systems is provided by X-STM and APT. This review presents an overview of detailed structural and compositional analysis that have assisted in improving the fabrication of QD based optoelectronic devices grown by droplet epitaxy.

Heterogeneous Oxidation and Precipitation of Aqueous Mn(II) at the Goethite Surface: A SPM Study

1998 ◽  
Vol 4 (S2) ◽  
pp. 600-601
Author(s):  
John Rakovan ◽  
F. Hochella Michael
Keyword(s):  
Lateral Force ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Mineral Surfaces ◽  
Tunneling Microscopy ◽  
Heterogeneous Oxidation ◽  
Force Microscopy ◽  
Solution Interface ◽  
Atomic Force

Since its invention inl982 scanning probe microscopy (SPM) has become an important analytical tool in every branch of physical science. The two most widely used types of SPM are atomic force Microscopy (AFM) and scanning tunneling microscopy (STM). Both AFM and STM allow measurement of the microtopography of a surface down to the atomic scale. Many spin-off applications such as lateral force and magnetic force allow measurement of a variety of the physical properties of a surface while imaging its microtopography. SPM can be done in both air and liquid and hence can be used to observe the interactions that take place at a solid-solution interface.SPM has been used in mineralogy and geochemistry since 1989. Here as in other applications the great strength of SPM is in the characterization of the heterogeneous nature of mineral surfaces and the ability to observe many geochemical processes in real time.

scholarly journals Topographic signatures and manipulations of Fe atoms, CO molecules and NaCl islands on superconducting Pb(111)

2022 ◽  
Vol 13 ◽  
pp. 1-9
Author(s):  
Carl Drechsel ◽  
Philipp D’Astolfo ◽  
Jung-Ching Liu ◽  
Thilo Glatzel ◽  
Rémy Pawlak ◽  
...  
Keyword(s):  
Co Adsorption ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Microscopy Imaging ◽  
Probe Microscopy ◽  
Functionalized Tips ◽  
Microscopy Techniques ◽  
Electronic And Structural Properties

Topological superconductivity emerging in one- or two-dimensional hybrid materials is predicted as a key ingredient for quantum computing. However, not only the design of complex heterostructures is primordial for future applications but also the characterization of their electronic and structural properties at the atomic scale using the most advanced scanning probe microscopy techniques with functionalized tips. We report on the topographic signatures observed by scanning tunneling microscopy (STM) of carbon monoxide (CO) molecules, iron (Fe) atoms and sodium chloride (NaCl) islands deposited on superconducting Pb(111). For the CO adsorption a comparison with the Pb(110) substrate is demonstrated. We show a general propensity of these adsorbates to diffuse at low temperature under gentle scanning conditions. Our findings provide new insights into high-resolution probe microscopy imaging with terminated tips, decoupling atoms and molecules by NaCl islands or tip-induced lateral manipulation of iron atoms on top of the prototypical Pb(111) superconducting surface.

The Atomic-Scale Characterization of Defects on Cleaved Vanadium and Molybdenum Oxide Surfaces Using Stm

1994 ◽  
Vol 357 ◽  
Author(s):  
Gregory S. Rohrer ◽  
Richard L. Smith
Keyword(s):  
Atomic Scale ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Coordination Polyhedra ◽  
Single Crystal Surfaces ◽  
Surface Plane ◽  
Crystallographic Shear ◽  
Scale Characterization ◽  
Reliable Interpretation

AbstractScanning tunneling microscopy (STM) was used to determine the structure of cleaved, single crystal surfaces of V205, V6013, Mo18052, and Mo8023. Constant current images were recorded in ultrahigh vacuum and in air. By imaging well-defined surfaces that exhibit structural and chemical similarities, and comparing the observations to the known bulk structures, it is possible to establish a reliable interpretation for the contrast in the STM images. A comparison of images from the V6013(001) and the V205(001) surfaces clearly shows that the surface V coordination polyhedra that are capped by vanadyl 0 can be distinguished from those that are not. This allows vacancies in the vanadyl 0 position to be identified on cleaved V205(001) surfaces. Mo18052(100) and Mo8023(010) provide models for two different characteristic types of surface/crystallographic shear (CS) plane intersections. The shear in Mo8023 lies in the (010) surface plane and creates dark contrast along the [001]. The CS planes in Mo18052, on the other hand, have components of shear both in and normal to the (100) surface plane and create white contrast parallel to [010]. These standards for contrast identification can be used to identify defects on inhomogeneous surfaces.

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