Semiconductor Diode

5.2

Semiconductor Diode

Semiconductor

A group of materials that conduct electricity better than an insulator but less efficient than metal conductors.

Elements commonly used as semiconductors include silicon, germanium and selenium.

	Doping process
	Process of adding small amounts of foreign atoms such as antimony and boron atoms.

Types of semiconductors

n-type semiconductor
- Silicone (4 valence electrons) is doped with pentavalent atoms such as antimony, phosphorus or arsenic to increase the number of free electrons.
- This silicone has electrons as the majority charge carrier.
p-type semiconductor
- Silicone is doped with trivalent atoms such as boron, indium and gallium which have more positive holes.
- This silicone has a positive hole as the majority charge carrier.

Semiconductor diode

It is obtained when the p-type and n-type semiconductors are combined.

It acts as a tool that allows the current to flow in one direction only.

The diode works in two ways:

Forward-biased
- The depletion layer shrinks, R decreases
- The junction voltage decreases
- The supplied V is higher than the junction voltage
- Current flows
Reverse-biased
- The depletion layer thickens, R increases
- The junction voltage increases
- The supplied V is lower than the junction voltage
- Current does not flow