Scanning tunneling microscope demonstration

Scanning tunneling microscope demonstration using 35 xenon atoms (Eigler and Schweizer. 1990). 

We want to point out that many analytical apparatus originally designed for room temperature have been modified to allow operation at low temperature with much better performances. An example is the STM (scanning tunnelling microscope) [1,2] which allows to image the morphology of a surface. Spectacular demonstrations have been provided of what could be done with a 4K STM [2,3], Today several low-temperature STM of different design are in operation [4-12],... 

The Scanning Tunneling Microscope has demonstrated unique capabilities for the examination of electrode topography, the vibrational spectroscopic imaging of surface adsorbed species, and the high resolution electrochemical modification of conductive surfaces. Here we discuss recent progress in electrochemical STM. Included are a comparison of STM with other ex situ and in situ surface analytic techniques, a discussion of relevant STM design considerations, and a semi-quantitative examination of faradaic current contributions for STM at solution-covered surfaces. Applications of STM to the ex situ and in situ study of electrode surfaces are presented. 

The main contaminants in an ionic liquid will be introduced from the synthesis, absorbed from the atmosphere or produced as breakdown products through electrolysis (see above). The main contaminants for eutectic-based ionic liquids will be from the components. These will be simple amines (often trimethylamine is present which gives the liquid a fishy smell) or alkyl halides. These do not interfere significantly with the electrochemical response of the liquids due to the buffer behavior of the liquids. The contaminants can be effectively removed by recrystallization of the components used to make the ionic liquids. For ionic liquids with discrete anions the major contaminants tend to be simple anions, such as Li+, K+ and Cl-, present from the metathesis technique used. These can give significant difficulties for the deposition of reactive metals such as Al, W and Ti as is demonstrated below with the in situ scanning tunnelling microscope. 

Constant height repulsive (pushing mode) manipulation of a Cm molecule covalently bound to the Si(OOl) surface is modelled using ab initio density functional theory, with the scanning tunneling microscope tip included explicitly in the calculations. The formation of chemical bonds between the tip and the molecule is demonstrated. The bonds between the molecule, tip and surface are constantly rearranging, so that a continuous manipulation process is possible. Tip-induced manipulation considered here is compared with the tip-free model, and the effects due to the tip are discussed. 

The methods that are commonly used to produce semiconductors and electronic materials are now being used in catalyst preparation. As recently reported, lithography has been used to deposit metal in predetermined patterns. Deposition of small clusters using nano-scale scanning tunneling microscopic tip has also been demonstrated. 

The industry roadmap specifies the need for chemically amplified resists that provide lithographic performance suitable to sustain their extension to 20 nm dimensional regime [522]. The ultimate resolution of 0.3 nm has been demonstrated by moving atoms at will with a scanning tunneling microscope [523] but the process is too slow to be economically feasible (one atom/min or... 

To demonstrate the insensitivity of some of the most modern surface science techniques to the structure of the second layer under the adsorbed molecule. Figure 11a shows a scanning tunneling microscope picture of a monolayer of graphite adsorbed on a platinum (111) surface. The graphite structure is clearly visible, but there is no information on the platinum atoms underneath the graphite. 

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