Basic Materials for Electronics: Conductor, Insulator and Semiconductor

Today electronics is very important in our modern life. We are surrounded by electronics devices. From morning to night, every time, every second we use electronic devices to accelerate our daily work, to make our life easier. Computer, TV, mobile and there are thousands of electronic device which are mode of diode, transistor and integrated circuits. To understand how these devices work, we first have to study and understand the semiconductor materials that neither conductors nor insulators. Semiconductor contains some free electrons but these amounts of electrons are not sufficient to use in practical application.

Depending on the conductivity or presence of electrons in a material, materials are divided into three categories.

                        1. Conductor                 
                        2.  Semiconductor          
                        3. Insulator

From Bohr’s atom model and from atom model, we know that a atom consists of three particle

            1.  Electron    
            2.  Proton and      
            3.   Neutron

 

Fig-1: Atomic Stracture

Proton is positively charged particle (Ve+) and it charge is 1.62×10^-19C and Neutron is neutral. These two particle forms the nucleus of the atom and electron rotates this nucleus at certain orbit or shells, which is negatively charged and its charge is - 1.62×10^-19C.

Valence Orbit and Valence Electron:

In electronics, all that matters is valence orbit and valence electrons. Valence orbit is the outer orbit of an atom and the electrons that stay in this orbit is called valence electrons. This orbit controls the electrical properties of atom.

Free Electrons:

The attraction between the core and the valence electron is very week, a small outside force can easily separate this electrons from their valence orbit and become free. That’s why we often call the valence electron a free electron.

Conductor:

Conductor

A conductor is an element whose resistivity is very low and conductivity is very high.  The best conductors are silver, copper and gold. The best conductors have one valence electron.

Insulators:

Insulator

A insulator is an element whose resistivity is very high and conductivity is very low. Good insulators are glass, wood etc. The best insulators have eight valence electron.

Semiconductor:

Semiconductor

A semiconductor is an element with electrical properties between those of a conductor and those of an insulator. Some common semiconductors are germanium, silicon etc. The best semiconductors have four valence electrons.