ABSTRACT
I must start this chapter with a word of warning. The p-n junction is often described as the simplest semiconductor device with which to start learning electronics. I won't quibble over the fact that simpler device structures exist (photoconductors, for example) since, structurally speaking, the p-n junction is quite simple. However, be warned. Understanding how the p-n junction actually works physically is in fact quite difficult! For those of you who have done a little electronics before, and are now using this book for your further education studies, who think you know how a p-n junction works, I can assure you, you don't. This may actually be the toughest chapter in the book, tougher even than the quantum mechanics section. It is arguably the most important device chapter in the book since the humble p-n junction takes us on to an understanding of the LED, the photodiode, the LASER and, of course, the bipolar transistor. This is therefore a fundamentally important chapter for an understanding of electronic devices.
