So I understand P and N type semiconductors and the depletion region makes sense.
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/pnjun.html (using this as reference for my question).
So the electrons diffuse across into the acceptor holes in the P region, this makes sense. Which leaves "positively" charged holes in the N region near the depletion region (as shown in the website above).
So 2 questions:
Why don't more electrons (in the N region) keep moving into the new positively charged holes near the depletion region? (from the N region). Is it due to the Negative Ions created? Is the depletion region electric field that strong? or is it because they are not Donor electrons and still in the valence band and aren't at the required energy levels to be excited up to the conduction band?
Same thing I suppose for the other side, why don't the electrons that just diffused over to the P region keep moving around into other holes in the P region (or to the left if you looking at the picture in the link above)