Maximum Built-In Voltage of a PN junction

[Corwin_S]

Hi,

I'm familiar with the expression for calculating the built-in voltage of a p-n junction. How can I find the maximum built-in voltage before the semiconductor becomes degenerate (i.e., a bad metal) if I only know the material and the intrinsic carrier concentration at a given temperature?

Unfortunately it is not as simple as taking a derivative and setting it to zero, because the derivative of the built-in voltage expression goes as 1/x.

Cheers

 

[nasu]

Can you define the "built-in voltage of a semiconductor"?

 

[Corwin_S]

Absolutely, look at 4.2.3 of this link for the standard formula:
http://ecee.colorado.edu/~bart/book/book/chapter4/ch4_2.htm

 

[nasu]

The formula (and the figure) refers to a junction and not to a semiconductor. This is what I found confusing.
Thank you for clarification.

 

[Corwin_S]

The formula (and the figure) refers to a junction and not to a semiconductor. This is what I found confusing.
Thank you for clarification.

I see! Indeed that was a mistake.