Suggestion:

As the secondary electron emission depend on the application (where the sensor is used), I suggest you to perform factorial experiments in which you vary the parameters (current, voltage, thickness o the coating etc...), so you get a computational model to optimize the thickness of the deposited layer.

https://en.wikipedia.org/wiki/Factorial_experiment

Thanks ALin,

Do you know where I can Simulate? Any Softwares or Programs?

You could search on the internet about this subject... there are a lot of software that could be use ...

http://www.reliasoft.com/doe/