Understanding Diode Barrier Potential and Its Role in PN Junction Diodes

Click For Summary
SUMMARY

The barrier potential in a PN junction diode is indeed equivalent to the 'forward voltage' specified in datasheets. When the applied voltage exceeds this barrier potential under forward bias conditions, the diode conducts. The conduction behavior of a diode is characterized by a continuous exponential function, as described by the Shockley equation, which illustrates that the forward characteristic is smooth rather than abrupt. At higher currents, ohmic effects begin to dominate the conduction process.

PREREQUISITES
  • Understanding of PN junction diode operation
  • Familiarity with barrier potential and forward voltage concepts
  • Knowledge of the Shockley equation and its implications
  • Basic principles of semiconductor physics
NEXT STEPS
  • Study the Shockley equation in detail to understand diode current-voltage characteristics
  • Explore the effects of temperature on diode performance and barrier potential
  • Investigate the role of recombination in the depletion region of PN junctions
  • Learn about the impact of ohmic effects on diode conduction at high currents
USEFUL FOR

Electrical engineers, semiconductor physicists, and students studying diode behavior and characteristics in electronic circuits.

Physicist3
Messages
103
Reaction score
0
Hi,

For a PN junction diode, am I correct in thinking that the barrier potential (due to depletion region and hole-electron recombination etc.) is the same as the 'forward voltage' quoted on datasheets? Also, when a forward bias condition is created and the applied voltage is greater than the barrier potential, am I correct in thinking that the diode will then conduct?
 
Engineering news on Phys.org
You've pretty much got it.
 
One thing people don't seem to get is that the conduction of a diode is a continuous exponential function.

From the wikipedia article:
"The diode is commonly said to have a forward "threshold" voltage, which it conducts above and is cutoff below. However, this is only an approximation as the forward characteristic is according to the Shockley equation absolutely smooth".

The flow is exponential relative to the barrier voltage until it is dominated by ohmic effects at higher currents.
 

Similar threads

Understanding the second approximation of diodes
  • · Replies 8 ·
Replies
8
Views
3K
Is my understanding of the working principle of a solar cell correct?
  • · Replies 1 ·
Replies
1
Views
1K
Fundamentals of the PN Junction
  • · Replies 12 ·
Replies
12
Views
3K
Undergrad Measuring the built-in potential of a pn junction
  • · Replies 10 ·
Replies
10
Views
3K
Help with the Key Points of Zener Breakdown and Avalanche Breakdown
  • · Replies 1 ·
Replies
1
Views
2K
What is the polarity of a Pn junction diode
  • · Replies 42 ·
2
Replies
42
Views
9K
Some fundamental questions about pn junctions
  • · Replies 10 ·
Replies
10
Views
3K
What Explains the Lack of Current in a PN Junction at Equilibrium?
  • · Replies 3 ·
Replies
3
Views
2K
Why does a transistor in saturation act like a short circuit?
  • · Replies 5 ·
Replies
5
Views
4K
Basic Semiconductor Questions: Answered!
  • · Replies 6 ·
Replies
6
Views
2K