# Semiconductors, Solid-State Physics

We know, that conductors, conduct because their valence energy band is "half" full, and k ("wave vector") can increase and therefore the electrons under the influence of a electric field can "move", and similarly insulators wont conduct, because ther valence band is full, and we have a "big" energy gap between the valence and conductivity band.

My question: Why can't under the infulence of a electric field electrons "jump" onto the next energy band (that's the conductivity band) , where their k ("wave vector") can increase "more freely" and therefore conduct electricity?

• It takes energy to make the jump but if the electric field is large enough you can make an insulator conduct. – Farcher Mar 4 '16 at 9:09
• So... under a large enough electric field electrons "jump" from the valence band onto the conductivity band? , or is that not the right way to understand this? – Luka8281 Mar 4 '16 at 9:22
• The strong electric field causes bound electrons to be ejected from atoms and become mobile charge carriers. – Farcher Mar 4 '16 at 9:25
• That means those electrons are in the conductivity energy band ? – Luka8281 Mar 4 '16 at 9:31
• What kind of electric field? From context, I think you mean a static or slowly varying field, not an optical, radio, or x-ray electric field. Can you clarify? – garyp Mar 4 '16 at 11:51