Holes can move through the material just as electrons do, and they contribute to the conductivity of the material as well. This is a difficult concept to grasp
; the idea of a hole is an abstraction, since the hole is not actually an object, like an electron, but rather the absence of an object. To help understand, consider that the hole exists in the Valence Band, not the conduction band (since it was created by an electron getting pulled from the Valence Band to the Conduction Band). Thus, electrons in other bonds can easily slide into that hole without requiring any extra energy. In that fashion, an electron from one bond can move into a hole left in another bond. Then, yet another electron from yet another bond can move into the hole left by the previous electron, and so on. Ad infinitum, ad nauseum
while the power is on. Later, Gil.