semiconductor diode

a diode is an semiconductor device which is used in various types of electronics instruments. It has two terminals positive and negative. the main feature which made the diode to be very useful is that it can allow the flow of current through it in only one direction called forward bias and it doesn't allow the flow of current through it in another direction. It consists of two type of semiconductor known as p-type and n-type. when they are fused together the nearer + and - fuses to form a depletion layer. so to cross the depletion layer by electrons some energy is needed.the following diagrams illustrate the introduction and characteristics of diode