Why study Semiconductor Physics

 Why study Semiconductor Physics

Semiconductor Physics:

We are already familiar with simple devices of electronics like the radio, television, calculator etc. If we look inside in these electronic devices we will find resistors, capacitors, inductors, transformers, semiconductor diodes, transistors and some IC’s. 

(In this website we already posted the article related to the resistors, capacitors, inductors and transformers, please read those article to know about these electronic components).

So we already know something about resistors, capacitors, inductors, and transformers, but small semiconductor devices likes diodes and transistors are new to us.

In the modern electronic systems, the whole electronic circuit, containing many diodes, transistors, resistors, etc.,

And these small semiconductors devices when fabricated on a single chip then this chip is called an IC. IC stands for Integrated Circuit.

Let us take a simple example of a semiconductor diode. It is a two terminal device. It has a very important property of conducting in only one direction.

In the following figure : a circuit is shown in which a battery, a bulb and a semiconductor diode is connected in series.

When the diode is connected in this manner, the bulb glows.

Now in the following figure: same above circuit is drawn but the only difference is the diode position . the diode position is opposite in this case. And when the diode is connected in this manner the bulb does not glow. It means no current is flowing in the circuit. Although the battery is present. The diode does not permit the current to flow.

Thus, we find that a diode conducts only in one direction only. This unidirectional conducting property of a diode finds great applications in electronics. The power available at the mains in our homes is generally AC, and we often required DC power to operate some appliances, the diode makes it possible to convert AC into DC.

 

Another important component is the transistor. The transistor is used for amplifying weak electrical signals. A transistor is a three terminal device.

 

Relatively newer devices, like

 

1. junction field-effect transistor (JFET),

 

2. metal-oxide semiconductor field effect transistor (MOSFET),

3. silicon controlled rectifier (SCR),

4. Unijunction transistor (UJT), etc.,

 

are finding wide applications in electronics. All these devices are made of semiconductor materials.