Semiconductor A substance that does not

Semiconductor A substance that does not conduct electricity at low temperatures but does so at higher temperamres. 

Many naturally occurring substances, in particular the oxide films that form spontaneously on some metals, are semiconductors. Also, electrochemical reactions are used in the production of semiconductor chips, and recently semiconductors have been used in the construction of electrochemical photocells. So there are good technological reasons to study the interface between a semiconductor and an electrolyte. Our main interest, however, lies in more fundamental questions How does the electronic structure of the electrode influence the properties of the electrochemical interface, and how does it affect electrochemical reactions What new processes can occur at semiconductors that are not known from metals ... 

The net flow corresponds to the difference of polar flows, its nullity being obtained by the equality of both polar flows. In this case, it does not mean that the exchange is stopped but it still exists without net result. This notion corresponds to the dynamic equilibrium met in a semiconductor junction or in reaction kinetics. The reversible chanical reaction between two substances A and B is symbolically represented with the help of opposite arrows labeled with the corresponding specific rate (kinetic constant) (see Figure 6.4). 

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