# PN junction

1. Apr 25, 2009

### iamlooting_yo

1. The problem statement, all variables and given/known data
Ideality factor and reverse saturation current

http://3.bp.blogspot.com/_h90yJnbZXIE/SfMcs8FCF8I/AAAAAAAAAFk/dJ7cnqLGntk/s1600-h/circuit_fordiodeparameterextraction.JPG
Use the circuit above to determine the I-V characteristic over 3 decades of current from 0.01 mA to 10 mA. Record the current and voltage values using the two DMMs and plot the I versus V date on a semilog graph paper.

Explain how you can determine the slope of the ln I versus V relationship from the semilog plot. From this graph, determine the ideality factor n and reverse saturation current I0.

I0 = 0.3nA (y-intercept of the graph from the semilog plot)
Gradient of ln I against V graph: q/nKT=ln⁡〖(9×〖10〗^3 )-ln⁡50 〗/(0.4-0.2)=25.96=26.0
Ideality factor, n=q/(26.0)KT=1/(26.0×0.0252)=1.53

2. Relevant equations

This is where I stuck:

Suggest an extension to this experiment by which the coefficient A of a diode in equation 6 can be determined

I0 =AT^3 e^((-Eg)/kT) (6)

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited by a moderator: Apr 24, 2017