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Barrier potential

by ranju
Tags: barrier, potential
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Jul19-14, 11:31 AM
P: 96
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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Simon Bridge
Jul20-14, 08:12 AM
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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?

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