Scanning Tunneling Microscopy of HF-Controlled Si(111) Surfaces

1992 ◽  
Vol 259 ◽  
Author(s):  
Hiroshi Tokumoto ◽  
Yukinori Morita ◽  
Kazushi Miki
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Surface Structure ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Smooth Surfaces ◽  
Tunneling Microscopy ◽  
Dry Air ◽  
Stm Images ◽  
Made In

ABSTRACTScanning tunneling microscopy (STM) was made in order to examine the surface structure and roughness in an atomic scale. The surfaces were prepared by several ways: NH4F (pH = 8) dipping just after RCA cleaning or after keeping in dry air for a few weeks; dipping into NH4F (pH = 8) solution or dipping into solutions with pH=10 just after boiling in HNO3. The STM images clearly showed that the surface structure and roughness are dependent on the sample treatments. The smooth surfaces with less defects were obtained for surfaces prepared by removing the HNO3-oxidized layer by NH4F (pH = 8) dipping.

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).

Applications of Scanning Tunneling Microscopy in the Materials Characterization Laboratory

1990 ◽  
Vol 48 (1) ◽  
pp. 316-317
Author(s):  
J.B Liu ◽  
Boyd Clark ◽  
R.M. Fisher
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Surface Structure ◽  
Surface Topography ◽  
Density Wave ◽  
Atomic Scale ◽  
Materials Characterization ◽  
Dimensional Structure ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Specimen Handling

Scanning tunneling microscopy, first developed by G.Binnig, H.Rohrer, Ch.Gerber, and E.Weibel [1] in 1982 as a method of directly observing atom sites at the surface of graphite and other crystalline materials, is now being used in an ever increasing variety of applications as a result of steady and rapid advances in instrumentation, interpretation, and specimen handling techniques [2]. As a result the STM is widely recognized as a powerful method of observing surface structure on an atomic scale and is fast becoming an accessory tool in materials characterization laboratories that are devoted to solving industrial problems. Some examples representative materials characterization studies are described in mis paper.The first STM studies employed its high resolution capabilities for fundamental studies of the topography of atoms at surfaces [2]. More recently the value of the STM to observe both surface topography and electronic structure has been utilized. Figure 1 is a STM image of a charge density wave (CDW) from a TaS3 sample at 143K[3]. In this work the advantage of STM, due to sensitivity to both surface topography and electron structure, is apparent.The development of long scan STMs with scan capabilities of several micrometers or more has opened up a whole new class of materials where the magnifications required are comparable to that of a conventional SEM. The 3-dimensional structure of a processed optical recording disk, as revealed by the STM, is illustrated in Figure 2. The ability of the STM to observe both the course and ultrafine structure of such a sample makes it a powerful tool for relating processing conditions to surface structure defects and hence to the quality and reliability of the optical storage disk itself.

Simulating Stm Images for the Gaas (110) Surface

1997 ◽  
Vol 492 ◽  
Author(s):  
James R. Chelikowsky ◽  
Hanchul Kim
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Ab Initio ◽  
Surface Structure ◽  
Gaas Surface ◽  
Scanning Tunneling ◽  
Semiconductor Surfaces ◽  
Tunneling Microscopy ◽  
Pseudopotential Calculations ◽  
Stm Image ◽  
Stm Images

ABSTRACTScanning tunneling microscopy (STM) is one of the most successful experimental tools for probing the structure of semiconductor surfaces. However, care must be taken in interpreting the images at the atomistic limit. Often a “naive” interpretation of the STM image can yield an incorrect surface structure. We illustrate this situation via ab initio pseudopotential calculations for the STM image of the (110) GaAs surface. We will compare theoretical STM images to experimental images for the relaxed surface and for a surface with an As vacancy.

Scanning tunneling microscopy of polymers: A status report

1989 ◽  
Vol 47 ◽  
pp. 330-331
Author(s):  
P.E. Russell ◽  
I.H. Musselman
Keyword(s):  
High Resolution ◽  
Scanning Tunneling Microscopy ◽  
Sample Surface ◽  
Atomic Scale ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Status Report ◽  
Tunneling Microscopy ◽  
Research Issues ◽  
Wide Range

Scanning tunneling microscopy (STM) has evolved rapidly in the past few years. Major developments have occurred in instrumentation, theory, and in a wide range of applications. In this paper, an overview of the application of STM and related techniques to polymers will be given, followed by a discussion of current research issues and prospects for future developments. The application of STM to polymers can be conveniently divided into the following subject areas: atomic scale imaging of uncoated polymer structures; topographic imaging and metrology of man-made polymer structures; and modification of polymer structures. Since many polymers are poor electrical conductors and hence unsuitable for use as a tunneling electrode, the related atomic force microscopy (AFM) technique which is capable of imaging both conductors and insulators has also been applied to polymers.The STM is well known for its high resolution capabilities in the x, y and z axes (Å in x andy and sub-Å in z). In addition to high resolution capabilities, the STM technique provides true three dimensional information in the constant current mode. In this mode, the STM tip is held at a fixed tunneling current (and a fixed bias voltage) and hence a fixed height above the sample surface while scanning across the sample surface.

Atomic-scale surface science phenomena studied by scanning tunneling microscopy

2009 ◽  
Vol 603 (10-12) ◽  
pp. 1315-1327 ◽  
Author(s):  
F. Besenbacher ◽  
J.V. Lauritsen ◽  
T.R. Linderoth ◽  
E. Lægsgaard ◽  
R.T. Vang ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Surface Science ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Scale Surface

Radical induced intermolecular linkage and energy level modifications of a porphyrin monolayer

2017 ◽  
Vol 53 (6) ◽  
pp. 1104-1107 ◽  
Author(s):  
Abdolreza Jahanbekam ◽  
Colin Harthcock ◽  
David Y. Lee
Keyword(s):  
Energy Level ◽  
Scanning Tunneling Microscopy ◽  
Surface Structure ◽  
Energy Levels ◽  
New Method ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Molecular Scale

A new method to directly modify the surface structure and energy levels of a porphyrin monolayer was examined with molecular-scale resolution using scanning tunneling microscopy and spectroscopy (STM and STS) and presented in this communication.

Reconstructed (12, 2, 7) Si surface structure observed by scanning tunneling microscopy

2000 ◽  
Vol 87 (2) ◽  
pp. 711-716
Author(s):  
Tsutomu Kawamura ◽  
Tomohide Kanzawa ◽  
Shiro Kojima ◽  
George A. Rozgonyi
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Surface Structure ◽  
Scanning Tunneling ◽  
Tunneling Microscopy
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