Semiconductors

 Semiconductors are materials whose conductivity lies between conductors and insulators. They are the main element for electronic circuits. There are two kinds of semiconductors; single element conductors and compound conductors. Compound conductors are very useful in electronic circuits.
 Silicon, mostly used in electronic circuits due to its conductivity controlling level and there is so much silicon in the world. It has 4 valance bonds, which means 4 covalent bonds with neighboring atoms. But it is not useful when it is pure because it doesn't give desirable conductivity while its intrinsic. So it needs to be doped.