Life Sciences Commons^™

New Methods For Depositing And Imaging Molecules In Scanning Tunneling Microscopy, Victor N. Morozov, Nadrian C. Seeman, Neville R. Kallenbach

Scanning Microscopy

Methods and apparatus are described to deposit and image molecules by scanning tunneling microscopy (STM) under an inert atmosphere. Three methods of applying molecules have been evaluated: equilibrium adsorption from the vapor phase, sublimation, and electrospraying. Using these methods, a variety of organic and biopolymer molecules have been deposited and imaged on graphite and on gold (111), grown epitaxially on mica. Compared with alternatives, such as the use of high vacuum apparatus or glove boxes, these procedures offer some important advantages: they are inexpensive, convenient, and more rapid. Mercaptoethanol, ethanolamine, ethanol, acetic acid, and water produce two-dimensional crystalline adlayers on …

Scanning Tunneling Microscopy: A Chemical Perspective, C. Julian Chen

Scanning Microscopy

In this review article, scanning tunneling microscopy (STM) is presented in a chemical perspective. The typical distance from the nucleus of the apex atom of the tip to the top-layer nuclei of the sample is 4-6 Å, where a strong attractive atomic force, i.e., a partial covalent bond, arises between the tip and the sample. The origin of the covalent bond is the back-and-forth transfer of electrons between two atoms, which Pauling has called resonance. While a bias voltage is applied between them, a net electron current in a specific direction arises. This tunneling current is a result of …

A Scanning Tunneling Microscopy Study Of Vanadium Oxide, Takanori Oshio, Yoshiyuki Sakai, Tohru Moriya, Shaw Ehara

Scanning Microscopy

Atomic resolution images of the (010) surface of a divanadiun pentoxide (V₂O₅) single crystal were successfully obtained by the use of a scanning tunneling microscope (STM).

The images of the filled states at sample bias voltage, Vs = -2 V and the empty states at Vs = +2 V correspond to oxygen and vanadium ions, respectively.

As for the vanadium ion sites, an additional peak of the electronic states at the conduction band edge due to the defects of vanadyl oxygen ions was found in the normalized conductance spectrum through the tunneling spectroscopy (TS) measurement.

Morphology Studies Of Iron-Manganese Thin Films, G. Mathew, K. -W. Ng, A. R. Sethuraman, J. M. Stencel

Scanning Microscopy

Fe-based catalysts are known to be effective for Fischer-Tropsch synthesis from coal but are sensitive to sulfur poisoning. Addition of manganese to these catalysts has been proposed in an effort to combat this catalyst deactivation. To investigate the fundamental physical aspects of Mn incorporation into Fe, different compositions of model thin films of Fe-Mn, ranging from 100% Fe to 100% Mn were studied for the very first time, using scanning tunneling microscopy (STM), atomic force microscopy (AFM) and scanning electron microscopy. Our preliminary results indicate that the grain size of iron varied from 50 nm to 150 nm using the …