Assertion: impurity | /r/CapableOf | give off electron
Facets:
Source sentences:
text: The generation of free carriers requires not only the presence of impurities, but also that the impurities give off electrons to the conduction band in which case they are called donors or that they give off holes to the valence band in which case they are called acceptors (since they effectively accept an electron from the filled valence band).