Reply To: Calculate EQE in CHARGE

[Khashayar Ghaffari]

Hi Arpan,

This is a very good question and helps clarify some of the terms used in previous posts here:

In the solar cell example we calculate photovoltaic efficiency; this is done by dividing the generated power ("P") by input power ("Psolar"). This is including the calculated current in CHARGE since P = J (current flux) x Voc.

On the other hand, in an article like our CMOS example here the output of interest is external quantum efficiency which is based on the collection/absorption ratios:

The original question here is regarding EQE for solar cell example; I assume then that the output of interest is related to carriers and not power. In any case, both types of efficiencies rely on the optical efficiency calculated in FDTD, and collection efficiency calculated in CHARGE. Aside from our published examples, I've seen different definitions of efficiency for optoelectronic devices across published works so the terminologies can be confusing.

If efficiency (photovoltaic or external) is needed vs wavelength, multiple CHARGE simulations are needed since one generation input is used in each run. I am not sure about the best approach to separate wavelengths; I would separate wavelengths without overlap unless you have more information about how the overlapping can be helpful e.g. increase accuracy.

Hope this answers all 3 of your questions.

Best regards