Fig. 5

a The lnσ-1/T plot with different P doping ratios. The value listed on each line is the corresponding conductivity activation energy E a . b The schematic drawing of the shift of Fermi level
a The lnσ-1/T plot with different P doping ratios. The value listed on each line is the corresponding conductivity activation energy E a . b The schematic drawing of the shift of Fermi level