Field dependent mobility not working?

device
mobility

#1

I’m trying to use the E-field-dependent mobility model in a transport simulation of a Silicon diode. I tried to activate this model by setting beta=1.3, and v_sat =1e7 V/cm in the ‘High Field’ electron mobility model settings in the material properties window of Lumerical Device. When I try to plot mobility (mun) vs field (F in V/m) using the ‘Visualize’ button, it appear to be constant up to 1e9V/m, where by the model it should be reduced by more than 100x. I have the same problem with GaAs, where field-dependent mobility appears to be enabled with default parameters by default. Am I doing something wrong? Does anybody know if the field dependent mobility model affects transport calculations? Maybe this is only an issue with the plotting function.

Any advice would be appreciated. Thanks!

Best,
Dodd


#2

Hi Dodd,

This looks like a shortcoming of the visualizer to me. The field-dependent mobility models do work in DEVICE. You can confirm this by visualizing the “mobility” dataset from the results available in the CHARGE solver region after a simulation. If you have the “high-field” mobility model turned on, you will see that the mobility for electron (mun) and holes (muh) will decrease with applied bias in the regions where the electric field is increasing.

Let me know if you need any help verifying this.

Cheers!


P-i-n Germanium photodetector with high field model