Hi. So we have all seen the band diagram of a PN junction. In order for the fermi level to be the same on both sides, the P bands are shifted up or the N bands are shifted down. Now that the fermi levels are equal, what would happen if you bent the diode into a ring (annulus) shape? How would the bands look that the second junction? Since the fermi levels are already aligned, it's hard for me to understand. Another thing that's puzzling me is the work function, i.e. the energy difference between the fermi level and the vacuum level. The work functions of N and P type Si are different. But what if we imagine a 1 meter long PN junction. If you measure the workfunction at either end, will you get the same number? I'm thinking you should since the fermi levels are equal.