ABSTRACT
This chapter discusses the behavior of semiconductors leads to an explanation of the behavior of the junction diode in electrical circuits. In terms of their electrical conductivity, materials can be grouped into three categories, namely conductors, semiconductors and insulators. The higher the resistivity of a material the lower is its conductivity. Conductors are metals, with insulators being polymers or ceramics. Semiconductors include silicon, germanium and compounds such as gallium arsenide. With a pure semiconductor, each hole is produced by the electron release and so it has an equal number of electrons and holes. With n-type material, the majority charge carrier is electrons and for p-type it is holes. However, in the n-type semiconductor it has electrons available for conduction and in the p-type semiconductor it has holes available for conduction. The junction diode is a device involving a pn junction and has a high resistance to the flow of current in one direction and a low resistance in the other.
