The text from book is:
1. Electron leaves negative terminal of the battery and enters the right end (N-type material) of the diode. 2. Electron then travels through the N-type material. 3. The electron nears the junction and recombines and becomes a valence electron. 4. The electron now travels through the P-type material as a valence electron. 5. The electron then leaves the diode and flows back to the positive terminal of the battery.
The electrons from N-type material combines with the positive ions in junction. And they become Valence electrons. But how do they cross the negative part of junction? Will not the electrostatic repulsion let it not cross it?
One solution I believe if my doubt is correct is that, the barrier electric field produced by depletion layer behaves like a battery with opposite polarity.
And thus the valence electron crosses because of the field and reaches to P-type material.
But this produces a contradiction when forward current keeps flowing and the depletion layer, so the barrier field, reduces after some time. Please correct me.