In terms of semiconductors, and electrons moving from the valence to conduction bands, how do the remaining electron holes contribute to electrical conductivity?

Also, can anyone provide a short qualitative description of the properties of an electron hole as I am not totally familiar with the concept?

basically, they behave like a positron. when an electron and a hole meet they cancel each other out and that bit of the semiconductor becomes inert. the holes are drawn towards areas of negative charge. thats about it really.

The often behave as if they were more massive than electrons/positrons, though.

The often behave as if they were more massive than electrons/positrons, though.

 

But so do electrons within semiconductors.