Extrinsic Semiconductors If NA 1017 cm3 at 300 K what is th
     Extrinsic Semiconductors If N_A = 10^17 cm^-3 at 300 K, what is the electron concentration? 
  
  Solution
here we need to know whitch type of transsistor is
ie for si ni=1.5*10^10;
for ge ni=2.34*10^13;
for GaAs ni=1.8*10^6;
based on the ni
electrron concentration n=(ni^2)/Na;
for si n=2.25*10^3;
for ge n=5.47*10^9;

