Learning Forum

[anael sedilot]

Dear Sir or Madame,

I am trying to simulate a photodiode following the same procedure as the one given in the example of the utc PD from lumerical. 

I have seen that during the first step (FDTD simulation for generation rate), it is considered that every photon absorbed will create an electron hole pair. I guess that in taht case the photons absorbed in the p and n doped layer of the device will also create an exciton which is not true since it is free-carrier absorption.

 

Is there a way to correct this ? I was thinking of removing the imaginary part of the doped layer but this will give a wrong result since absorption will decrease in the device... How to take the free carrier absorption into account in this case ? 

 

For example is it possible to limit the area of exciton generation to the intrisic region of the device ? if so what should be change in the generation rate analysis script ?

 

Thank you in advance for your help

 

Best regards

[Guilin Sun]

Yes I agree that photons are not 100% converted to n-p carriers. For excitons it can be  modeld by such as radiative recombination. If you do not want such excitons, you can simply ignore such recommbination. Such recombinations are material based. so it is possible to limit the aear of exitons with proper material properties.

Please note that the simulation accuracy can only be as accurate as your simulation model, with infinitely small mesh.