Self-assembled monolayer

The self-assembled monolayer (English self- assembled monolayer, SAM) is an important part of nanotechnology. A self-assembled monolayer forms spontaneously upon immersion of surfactants or organic substances in a solution or suspension. Suitable substances are, for example, alkanethiols, alkyltrichlorosilanes and fatty acids. These form on metals such as gold, silver, platinum and copper and graphite and silicon simple monolayers with a high internal order. In general, the formation of ordered layers is observed only on terraces of single crystals of defects such as dislocations and kinks observed a different behavior. Such treated surfaces are stable in air for months. In contrast to conventional coating processes such as chemical vapor deposition ( chemical vapor deposition Sheet CVD) have a defined thickness of the SAM, which is used depending on the molecule in the range of 0.1 nm to several nanometers. The sensitivity of organic layers to reactive gas can be visualized using scanning tunneling microscopy. On the basis of these potential reactivity organic monolayers are often tested in ultra-high vacuum.

In the semiconductor technology, the self-assembled monolayer is used for stabilization and tailored surface functionalization of electrodes. Depending on the length of the alkyl chains used and the permeability of the charge transfer rate is influenced. The field of application of SAM - modified electrodes is very wide. Among other things, the technique of self-assembled monolayer is used in the electrochemical scanning tunneling microscope in cell studies, sensors and nanoelectronics.