A P-N junction is created by combining a P-type and an N-type component, resulting in a semiconductor diode. In N-type semiconductors, the majority of charge carriers are free electrons, while in P-type semiconductors, holes dominate the circuit. When an N-type semiconductor is joined with a P-type, you get a P-N Junction semiconductor diode. You can also define this semiconductor diode as a two-terminal device that permits electric current to flow in one direction and blocks it from flowing in the opposite direction.
When the diode is forward-biased, it allows the flow of electric current. In forward biasing, the positive terminal of a battery is connected to the P-type semiconductor, and the negative terminal is linked to the N-type semiconductor. Moreover, in reverse-biased conditions, where a voltage is applied in the opposite direction, it blocks the electric current.
Semiconductor materials like silicon, germanium, and gallium arsenide are used to create PN junction diodes, where Silicon is commonly preferred over germanium. This is because Silicon-based diodes are more affordable and can work at higher temperatures compared to germanium-based ones.
What are Forward Bias Voltages of Silicon and Germanium Diodes?
When the silicon diode is forward-biased, it requires a voltage of 0.7 volts (forward bias voltage) to start the flow of current. If you apply anything below 0.7 Volts, the silicon diode acts as an insulator and blocks the electric current.
On the other hand, a germanium diode has a lower forward bias voltage and needs 0.3 volts to start the current flow. This means that if the voltage applied to a germanium diode is less than 0.3V, it prevents current flow. However, if you apply 0.3 volts or anything more than that, the germanium diode starts conducting.
Also See: What is Homojunction?
What are the Advantages of P-N Junction Semiconductor Diode?
The basic advantages of this diode in various electronic applications are:
1. It helps in converting alternating current (AC) to direct current (DC) in power supply devices.
2. The diode acts as a switch in digital electronics as logic circuits. When you make it forward-biased, you turn it on (short circuit) by allowing current to flow, If it is reverse-biased, it indicates off condition (open circuit) and blocks the current. This switching behavior is very useful in electronic circuits, especially, in digital circuits.
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