A question about Schockley's Diode Equation

[alfred_duj]

Can anyone help me what is the difference between:

Id=Is(e^(kV/Tk)-1)

and

Id=Is(e^(vd/nVt)-1)?

Thank you!

 

[ssankurathri]

hi,

I = Is( exp(Vd/nVT) - 1) ---------------eq.1

where

I is the diode current,
IS is a scale factor called the saturation current,
VD is the voltage across the diode,
VT is the thermal voltage,
and n is the emission coefficient, also known as the ideality factor. The emission coefficient n varies from about 1 to 2 depending on the fabrication process and semiconductor material and in many cases is assumed to be approximately equal to 1 (thus the notation n is omitted).
The thermal voltage VT is approximately 25.85 mV at 300 K, a temperature close to “room temperature” commonly used in device simulation software. At any temperature it is a known constant defined by:

VT = kT/q
where

q is the magnitude of charge on an electron (the elementary charge),
k is Boltzmann’s constant,
T is the absolute temperature of the p-n junction in kelvins

If we substitue VT (called " volt equivalent temperature") value in eq.1, u will get another equation.


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