Most of the technology that we use every day and modern electronics is heavily dependent on semiconductors. We use semiconductors in telephones, computers, all digital technology and anything that uses radio waves to work. The most common devices that are made of semiconducting material is the diode and the transistor.
The simplest form of a semiconducting device is the diode. The resistivity value of a semiconductor lies between that of an insulator and a conductor. The ability to conduct electricity by a semiconductor can be varied by applying an external electric field.
Semiconductors can be made of a single element or a combination of materials. In the earlier days, germanium was used to make semiconducting devise. Now, silicon is the most common material used to produce semiconductors commercially. Other materials may also be used such silicon carbide. The conductivity of the semiconductor can be hugely varied by a process called 'doping'.
Doping is when other elements, called 'impurities' are added to the semiconducting material in a melted state. When this new combination of material solidifies, the new crystal structure is different in formation to the intrinsic semiconducting material.
The impurity is added when the intrinsic material is a melted state so when the new combination solidifies, the arrangement of the electrons around the atom is changed.
The two types of doping n-type and p-type which refers to the resultant overall charge of the material after doping. N-type causes a negative charge and p-type a positive charge.
With metals, it it is difficult to control the amount of electricity flowing through them as they will conduct almost under any condition. Semiconductors allow us to control the flow of electrons in them making it very useful.
The main difference between metals and semiconductors is that it is very difficult to control electricity flow in a conductor. The power to control the flow of electrons in a semiconductor allows us to use them in devices where current flow needs to be changed such as in switches and amplifiers.
