# Semiconductor notes and topic for boards class 12 Physics (Handwritten)

Materials are divided on the basis of their conductivity. If materials conduct electricity, its a metal and if it does not then conduct it’s an insulator, but there is a third category as well which lies between these two, which is known as semiconductor.

A semiconductor is a material that can behave like an insulator but shows conductivity depending upon the surroundings and situation. Due to this nature of semiconductor, we can even control the flow of electrons in a circuit with the help of them.
In this article, I am going to provide you with some basic details about semi-conductors as well as if you are a class 12 student then I am going to give you important topics from chapter 14 Semiconductor.

## What is a semiconductor ?

As I told you earlier semiconductor lies between metal (conductors) and non-metal (insulators) therefore it behaves like an insulator and doesn’t conduct electricity but depending upon the situation it can also conduct electricity and behave like an insulator.

### Semiconductor classification on the basis of resistivity and conductivity:

How did we know about all these things that a particular material will conduct in same condition and in some it will not?

Well for that let’s divide solids on the basis of the relative value of electrical conductivity (σ) or resistivity (ρ) and classify them as:

a. Metal: Metals posses very low resistivity and high conductivity which means they can easily conduct electricity.

b. Semiconductor: As I told you earlier, there resistivity and conductivity lies between metal and an insulator.

c. Insulator: They have high resistivity and low conductivity due to which they don’t conduct electricity.

## Important topics:

Important topics from Semiconductor for boards are Energy Band, Semiconductor basics, p-n junction and Optoelectronic Devices such as solar cell, photodiode, and Zener diode.

For 1 marker and MCQ for class 12 boards, conceptual questions from these topics as well as a photodiode and p-n junction questions can be asked.

All these topics are provided in the notes given below, they are highly in-depth class 12 physics notes of Ray optics so refer to them, it’s more than enough for boards.

## Handwritten Notes:

This article is a brief summary of chapter 14, Semiconductor for all the derivation related to this chapter and other important things. I have prepared my special handwritten notes. These notes have all the derivation of this chapter and important topics for your board exam 🙂