Characterization of Epitaxial Fe on GaAs(110) by Scanning Tunneling Microscopy

1989 ◽  
Vol 151 ◽  
Author(s):  
R. A. Dragoset ◽  
P. N. First ◽  
Joseph A. Stroscio ◽  
D. T. Pierce ◽  
R. J. Celotta
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Lattice Mismatch ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Small Lattice ◽  
Low Coverage ◽  
Substrate Temperatures ◽  
Stm Images ◽  
Interesting System

ABSTRACTIron on GaAs(110) comprises an interesting system not only due to small lattice mismatch, 1.4%, but also because of the magnetic properties of the overlayer. In the present work, scanning tunneling microscopy (STM) was used to investigate bcc Fe films in the 0.1 Å to 20 Å thickness range, grown at 300 K and 450 K substrate temperatures. STM images show Volmer-Weber growth with the formation of 3-D Fe islands 20–30 Å in diameter for 0.1–1 Å deposition at 300 K, increasing to 40–50 Å for thicker films. Iron island sizes at low coverage and thin film roughness at higher coverages both show significant dependence upon growth temperature.

Characterization of Dislocation Reactivity and Dynamics in Thin Metal Films Using Scanning Tunneling Microscopy

2000 ◽  
Vol 6 (S2) ◽  
pp. 702-703
Author(s):  
R.Q. Hwang
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Chemical Properties ◽  
Metal Films ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Cu Film ◽  
External Forces ◽  
Complex Phenomena ◽  
Stm Images

The accommodation of strain in metal films can lead to complex phenomena, both structurally and chemically. It can generically lead to the formation of dislocations. These dislocations play an important role in defining the evolution and response of the film to further growth and external forces. The structures of the dislocations are directly analogous to bulk dislocations, but their properties are very different due to the presence of the surface. In addition, the strain can greatly affect the chemical properties of the film, leading to alternative strain relief mechanisms involving vacancy formation resulting from reaction with gases such as sulfur and oxygen. Using STM and LEEM, we have investigated these phenomena in the prototype systems of Cu and Ag on Ru(0001).For example, figure la - d shows a sequence of STM images of a 2 layer Cu film on Ru(0001) during exposure to oxygen. Dislocations present in the film are altered by reaction with oxygen.

THE LOW COVERAGE PHASES OF Pb ON Ge(001): SCANNING TUNNELING MICROSCOPY AND FIRST PRINCIPLES

2002 ◽  
Vol 09 (05n06) ◽  
pp. 1809-1814
Author(s):  
NOBORU TAKEUCHI ◽  
G. FALKENBERG ◽  
R. L. JOHNSON
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Packing Density ◽  
First Principles ◽  
Density Functional ◽  
The Other ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Experimental Bias ◽  
Low Coverage ◽  
Stm Images

Using scanning tunneling microscopy and first principles total energy calculations, we have studied the atomic structure of the low coverage phases of Pb on Ge(001): the (2 × 2) and the c(4 × 8)- α reconstructions. Based on the analysis of the experimental bias-dependent STM images and supported by the ab initio pseudopotential density-functional calculations, we present models for each structure. In both cases, there is a coexistence of Ge and Pb dimers. The (2 × 2) phase is formed by asymmetric Pb dimers parallel and in the trenches between the underlying Ge dimers. The Pb coverage is 0.5 ML and it corresponds to the maximum packing density of Pb dimers without breaking Ge dimers. The c(4 × 8) - α reconstruction has a Pb coverage of 0.75 ML and it is characterized by asymmetric Pb dimers forming chains along the [110] direction. However, in this case half of the Ge dimers are broken. The other half remain intact and they are perpendicular to the Pb dimers.

Scanning Tunneling Microscopy of Amorphous Carbon Films

1990 ◽  
Vol 48 (1) ◽  
pp. 318-319
Author(s):  
Mircea Fotino ◽  
D.C. Parks
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Amorphous Carbon ◽  
Carbon Films ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Amorphous Carbon Films ◽  
Image Optimization ◽  
Step Procedure ◽  
Stm Images

In the last few years scanning tunneling microscopy (STM) has made it possible and easily accessible to visualize surfaces of conducting specimens at the atomic scale. Such performance allows the detailed characterization of surface morphology in an increasing spectrum of applications in a wide variety of fields. Because the basic imaging process in STM differs fundamentally from its equivalent in other well-established microscopies, good understanding of the imaging mechanism in STM enables one to grasp the correct information content in STM images. It thus appears appropriate to explore by STM the structure of amorphous carbon films because they are used in many applications, in particular in the investigation of delicate biological specimens that may be altered through the preparation procedures.All STM images in the present study were obtained with the commercial instrument Nanoscope II (Digital Instruments, Inc., Santa Barbara, California). Since the importance of the scanning tip for image optimization and artifact reduction cannot be sufficiently emphasized, as stressed by early analyses of STM image formation, great attention has been directed toward adopting the most satisfactory tip geometry. The tips used here consisted either of mechanically sheared Pt/Ir wire (90:10, 0.010" diameter) or of etched W wire (0.030" diameter). The latter were eventually preferred after a two-step procedure for etching in NaOH was found to produce routinely tips with one or more short whiskers that are essentially rigid, uniform and sharp (Fig. 1) . Under these circumstances, atomic-resolution images of cleaved highly-ordered pyro-lytic graphite (HOPG) were reproducibly and readily attained as a standard criterion for easily recognizable and satisfactory performance (Fig. 2).

Electronic trap characterization of the Sc2O3∕La2O3 high-κ gate stack by scanning tunneling microscopy

2008 ◽  
Vol 92 (2) ◽  
pp. 022904 ◽  
Author(s):  
Y. C. Ong ◽  
D. S. Ang ◽  
K. L. Pey ◽  
Z. R. Wang ◽  
S. J. O’Shea ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Gate Stack

Manufacturing and Characterization of Nanostructures Using Scanning Tunneling Microscopy with Diamond Tip

2016 ◽  
Vol 42 ◽  
pp. 14-46 ◽  
Author(s):  
Oleg G. Lysenko ◽  
Vladimir I. Grushko ◽  
Sergey N. Dub ◽  
Eugene I. Mitskevich ◽  
Nikolay V. Novikov ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Measuring System ◽  
Scanning Tunneling ◽  
Surface Load ◽  
Tunneling Microscopy ◽  
Electromagnetic Probe ◽  
High Pressure High Temperature ◽  
Single Crystal Diamond ◽  
Selection Of

Nanoscale experiments with diamond tip that include processing, visualization and tunneling spectroscopy of the surface are presented. Single crystal diamond synthesized by the temperature gradient method under high pressure–high temperature (HPHT) conditions is proposed as a multifunctional tip for scanning tunneling microscopy (STM). Sequence of the procedures covering growing crystals with predetermined physical properties, selection of the synthesized crystals with the desired habit and their precise shaping have been developed. The original STM’s peculiarity is the electromagnetic probe-to-surface load measuring system. The results of fabrication and characterization of nanostructures for nanoelectronics, data storages and biology are demonstrated and discussed.

Sign in / Sign up

Export Citation Format

Share Document