Heterogeneous de-excitation of electronically excited particles

The diversity of EEP reactions on a solid surface can be illustrated by the survey if interaction between excited atoms of mercury and zinc oxide [186]. When atoms of Hg get to an oxidized surface of ZnO at room temperature, an increase in the semiconductor electrical conductivity take place (Fig. 5.3, curve 2). The electrical conductivity change signal is irreversible, and in case of an increase in the temperature, after the Hg flux is disabled, an additional increase in the electrical conductivity (curves 3 and 4) takes place. One can logically suppose that we are dealing here with partial reduction of zinc oxide according to the scheme 

TRANSFER TO SCUD BODY Oikiiutiaa of ckBenUiyadtitiaBi EiarmiBnaa etc) kr Z Ut 

The superstoichiometric zinc yielded as the reaction proceeds ionizes by giving an electron to the ZnO conduction band. Thus, the electrical conductivity of the semiconductor increases. A competing process that determines the beyond cutoff lengths of the curves in Fig. 5.3 is represented by the reaction 

1 - admission of unexcited mercury vapour (the straight line merges into the abscissa) 2 - film temperature is 25 C 3 - 100 C 4 - 200 C. The dashed line designates the instant the source of Hg is switched off. 

Concentration of superstoichiometric zinc increases in series 2 3 films are at room temperature 

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