Emission of alkyl radicals from disordered selenium surface

Emission of alkyl radicals from disordered selenium surface 

To conduct experiments of this kind it is very convenient to make use of disorder adsorbent provided by a film of amorphous selenium. During deposition under vacuum conditions, the pressure being no higher than lO Torr, the amorphous modification of selenium is being formed [38]. There are two forms of amorphous selenium which differ in coordination numbers and radii of coordination spheres. The first form is 

Interaction of atomic hydrogen and selenium is accompanied by formation of volatile hydride, therefore the use of H-atoms as adsorbate is not convenient. From this stand-point it is better to use aliphatic radicals which are ready to interact with selenium [22]. 

The experiment with films of amorphous selenium with adsorbed ethyl radicals [39] showed that during heating of these films in vacuum 

If heating of amorphous selenium with absorbed ethyl radicals is conducted in presence of nitrogen or inert gas with pressure 100 Torr no signal is picked up from the sensor. This implies that in this case the signals of the sensor are controlled by adsorption of ethyl radicals on its surface. Consequently, the heating of amorphous selenium with adsorbed radicals and resulted crystallization lead to emission of radicals. 

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