I have the following two questions in the derivation of current in a diode.
1) In forward bias, an assumption "abrupt junction" is made and field is equal to 0 is also made. But then we still use built in potential. How is this okay?
2) In most semiconductor classes and also in Millman and Halkias they have left reverse bias case as similar. But can anyone help me out with the actual derivation? Because i don't see how the exponential decrease in hole concentration with distance occurs if the field is non zero in the continuity equation
Any help would be appreciated. Thanks