Conductor

There are dozens of free electrons can move freely at no any group in conductor Electrons charged (-) get moved by electric field conductor has. That is called “Electric Current” which electric charge had moved. When if electric current occurs, it gets electric field at short time in conductor and it goes away along rearrangement of electrons. I.e, conductor means by the thing let current get flown by a lot of free-electrons

Insulator

It is the opposite concept of conductor. People often know insulator As non-conductive electricity, but it goes through a little bit of electricity or heat. That is, there is nothing non-conductive electricity or heat. Even water is conductor but, non-ionic water is a insulator. Also, Insulator can be conductor when it has high-temp. or high-electric field or dopants.

Semi-conductor

Semi-conductor has the mid-character of conductor and insulator Conductor is conductive, Insulator is non-conductive. Semi-conductor does not have free-electrons at ease, but that gets them at excited state. Generally, Semi-conductor materials refer to Ge, Si on 14 group in periodic table. Semi-conductor research was started with Ge, it is being studied with Boron(12 Group)&Phosphorus(15 group) as dopants into Si-wafer. Nowadays, it is sometime used to a chemical component to 13 groups and 15 groups.