1.in band diagrams, books usually show parabolic bands for the conduction band and the valence band. They will also make note of the acceptor and donor leves in the band gap. However, they always draw straight horizontal lines for these levels. Is that correct? The impurity levels are independent of k? 2. Another thing that really bothers me about band diagrams is when people draw them filled. If I understand things, electrons can only exist in states on the actual curve of the band. For instance the conduction band at k=0 is parabolic and at energy 0. There cannot be an electron at k=0 at energy E above E=0 (unless it's on another band). I'm correct, right?