Barrier Potential: Explaining the Contradiction

In summary, the equation for the barrier potential is directly proportional to temperature, indicating that an increase in temperature should lead to an increase in the barrier potential. However, a statement contradicts this by stating that as temperature increases, more minority charge carriers are produced, causing a decrease in the barrier potential. This indicates that the equation for the barrier potential does not take into account the minority carrier concentrations. Further clarification is needed on the effects of temperature on the barrier potential.
  • #1
ranju
223
3
The equation for the barrier potential is as follows:

Vb = Vt loge(Na*Nd/square(n)) mV
where Vt=KT/e

This equation shows that the barrier potential is directly proportional to the temperature. So as temperature increases the barrier potential should increase.

But in contradiction to this, I have found the following statement:

" With increase in temperature, more minority charge carriers are produced, leading to their increased drift across the junction. As a result, equilibrium occurs at a lower barrier potential. It is found that the Vb decreases by about 2 mV/0C

Please explain...
 
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  • #2
There is more than one effect happening here.
Presumably the equation for the barrier potential did not take into account the minority carrier concentrations.
Where are you reading this?
 

FAQ: Barrier Potential: Explaining the Contradiction

What is barrier potential?

Barrier potential refers to the energy barrier that exists between a p-n junction in a semiconductor material. It is created by the difference in charge concentration between the p-type and n-type regions, resulting in a potential energy difference that impedes the flow of current.

How does barrier potential work?

Barrier potential works by creating a barrier that prevents majority carriers (electrons in n-type material and holes in p-type material) from crossing from one region to the other. This barrier is created by the electric field at the p-n junction, which is formed by the difference in charge concentration.

Why is barrier potential considered a contradiction?

Barrier potential is considered a contradiction because it creates an energy barrier that inhibits current flow, yet it is also necessary for the functioning of many electronic devices. This apparent contradiction is explained by the fact that barrier potential can be manipulated and controlled to allow current flow under certain conditions.

What are some practical applications of barrier potential?

Barrier potential has many practical applications in electronic devices, such as diodes, transistors, and solar cells. In diodes, barrier potential is used to control the direction of current flow, while in transistors it is used to amplify and switch electronic signals. In solar cells, barrier potential helps to convert light energy into electrical energy.

How can barrier potential be affected?

Barrier potential can be affected by various factors, such as temperature, doping concentration, and external voltage. Higher temperatures can decrease barrier potential, making it easier for current to flow, while changes in doping concentration can alter the barrier height. Applying an external voltage can also manipulate the barrier potential, either increasing or decreasing it depending on the direction of the voltage.

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