What is a semiconductor diode anyway?
A semiconductor diode is as its name suggests made out of a semiconductor which in this case is silicon, another common type is germanium. In the case of the silicon diode it is made up of two types of silicon. The p (positive) and n (negative) parts of the diode are made by mixing in with the silicon chemical impurities. One forces the new material to have extra electrons orbiting the silicon atoms were as the other causes there not to be enough electrons in the outer shell of the silicon atoms, these are referred to as holes. This gives you two types of silicon when two of these different materials are put together to form a pn junction a very strange thing happens. Around the contact area between the two materials the extra electrons move into orbit around the silicon atoms with less electrons. So the n material is in fact positive and the p region is negative. This has the effect of creating an area of neutral potential were the two substances meet so there are no atoms short of el
