I wanted to start this question by giving my understanding of the make up of a PN junction. I do this so that you can pick me up on anything that I may be getting wrong in the lead up to my question.
I have been doing some research into PN junction diodes and understand that you have one junction which is formed by a p-type region and an n-type region. These two regions have been doped with impurities to give an excess of electrons (free electrons) in the n-type region and a deficit of electrons (free holes) in the p-type region. However due to imperfect manufacturing techniques, we also get minority carriers in the p and n type regions which means that the n-type has some atoms which have a deficit of electrons (free holes) and in the p-type we have some atoms which have an excess of electrons (fee electrons).
Now my question is this - how is it possible that these minority carriers exist? Wouldn't they just combine with the majority carriers?