Update 14_doping_and_devices_solutions.md

src/14_doping_and_devices_solutions.md

@@ -36,14 +36,12 @@ Check both cases with lecture notes approximated solutions by doing a Taylor exp
 If all the dopants are ionized, the Fermi level gets shifted up towards the conduction band.
 This result can be obtained when using results in Exercise 1 - Subquestion 2 and the following:
 
-$$ n_D \approx 0$$
 $$ n_e - n_h = N_D - N_A $$
 
 
 ### Subquestion 2
 Now,
-$$ n_D^{\ast} = N_D (1-\frac{1}{e^({E_D-E_F})/k_BT+1})$$
-$\ast$ indicates non-ionized concentrations.
+$$ n_D = N_D\frac{1}{e^({E_D-E_F})/k_BT+1} $$
 ### Subquestion 3
 
 ??? hint "how?"