intrinsic Fermi level formula might be wrong
see https://moodle.epfl.ch/mod/forum/discuss.php?d=91594#p176881
instead of
E_{fi}=\frac{E_c+E_v}{2}-\frac{kT}{q}\ln{\frac{N_c}{N_v}}
it prefer, to fix the units... but I'm not sure:
E_{fi}=\frac{E_c+E_v}{2}- kT \ln{\frac{N_c}{N_v}}