Doubt in semiconductor diode theory ?

In summary, the conversation discusses the concept of current flow in a semiconductor diode. The forward biasing of the diode causes electrons and holes to recombine and eliminate each other, but the current flow is still attributed to the movement of electrons. It is explained that the holes do not actually move, but rather act as vacancies for the electrons to jump into.
  • #1
munna007
34
0
doubt in semiconductor diode theory ?

hello friends :smile:...

in this picture diode is forward biased. positive terminal of battery repel holes n negative repel electrons , finaly electrons n holes recombine n eliminate each other.

but its said that current flow is due to electrons . but electrons -holes both are eliminated. then how can we say that current flow is due to electrons.
?
how can they come out of both terminals of battery as they are eliminated inside ...?

please clarify my confusion...
 

Attachments

  • DSC00026.jpg
    DSC00026.jpg
    29.3 KB · Views: 425
Engineering news on Phys.org
  • #2


munna007 said:
finaly electrons n holes recombine n eliminate each other.
but electrons -holes both are eliminated. then how can we say that current flow is due to electrons.
?
how can they come out of both terminals of battery as they are eliminated inside ...?
It is not like that. The current outside the diode terminals (i.e., in the wire) is due to flow of electrons only. But inside the diode, the holes actually did not move. It is the electron which move forward and leaves a hole in backward direction, so as the electron progresses, it appears that hole moves in opposite direction to that of electron. It is a steady state process in forward biased diode, since new electrons come in through N side and after passing through P it reaches the battery and completes its path.
 
  • #3


The "holes" (positive) don't move. Only the electrons move. Then the electrons jump to the battery leaving the "hole" for the next electron to jump into.
 
  • #4


oki understand now...i think hole is actually a vacancy for electron. it can not move...

thanks friends.
 

Related to Doubt in semiconductor diode theory ?

1. What is a semiconductor diode?

A semiconductor diode is a two-terminal electronic component that allows current to flow in only one direction. It is made of a semiconductor material, typically silicon, with two layers of different doping. The boundary between these layers is called the junction, which gives the diode its unique properties.

2. How does a diode work?

A diode works by utilizing the properties of the junction between two layers of semiconductor material. The P-type layer has an excess of positively charged holes, while the N-type layer has an excess of negatively charged electrons. When a voltage is applied across the diode, the holes and electrons are attracted to the opposite layer, creating a depletion zone in the middle. This depletion zone acts as a barrier to current flow in one direction, allowing current to flow freely in the other direction.

3. What is reverse bias and forward bias in a diode?

Reverse bias refers to the condition where the voltage applied to a diode is in the opposite direction of its normal operation. In this state, the depletion zone widens, and current flow is greatly reduced. Forward bias, on the other hand, refers to the condition where the voltage applied to the diode is in the same direction as its normal operation. This decreases the width of the depletion zone, allowing current to flow more easily through the diode.

4. What is the purpose of a diode in a circuit?

A diode serves many purposes in a circuit, such as rectifying alternating current (AC) into direct current (DC), protecting components from reverse polarity, and regulating voltage. In AC-DC power supplies, diodes are used to convert the incoming AC current into DC current. They are also commonly used in voltage regulators to maintain a steady output voltage.

5. How does temperature affect the performance of a diode?

Temperature can greatly affect the performance of a diode. As the temperature increases, the number of charge carriers in the semiconductor material also increases, leading to a decrease in the width of the depletion zone. This can cause the diode to conduct more current in the reverse direction, leading to potential failure. It is important to consider the operating temperature range of a diode when designing a circuit to ensure its proper functioning.

Similar threads

I have a question about diodes and the PN junction
    • Electrical Engineering
Replies
2
Views
951
Semiconductor -- Conduction and Valence bands
    • Electrical Engineering
Replies
1
Views
797
Understanding the second approximation of diodes
    • Electrical Engineering
Replies
8
Views
2K
Some fundamental questions about pn junctions
    • Electrical Engineering
Replies
10
Views
2K
Fundamentals of the PN Junction
    • Electrical Engineering
Replies
12
Views
1K
I am confused -- how to bias the diode in a boost converter?
    • Electrical Engineering
Replies
23
Views
2K
Diffusion current and carrier concentration equilibrium (unbiased)
    • Electrical Engineering
Replies
1
Views
945
Help with the Key Points of Zener Breakdown and Avalanche Breakdown
    • Electrical Engineering
Replies
1
Views
910
Why does a transistor in saturation act like a short circuit?
    • Electrical Engineering
Replies
5
Views
2K
What is the polarity of a Pn junction diode
    • Electrical Engineering
2
Replies
42
Views
8K

Hot Threads

Recent Insights

Back
Top