The p-n junction diode is among the oldest semiconductor devices. It was mainly used as mixers in the 1940s during World War II. The theory for the p-n diode was developed later by Shockley in 1949,1 and it was instrumental in the invention of the bipolar junction transistor. The theory was subsequently refined by Sah et al.2 and Moll.3 More recent review articles on the device can be found in Refs. 4-7. The p-n junction has been the most common rectifier used in the electronics industry. It also serves as a very important fundamental building block for many other devices.