Update 14_doping_and_devices_solutions.md

src/14_doping_and_devices_solutions.md

@@ -13,7 +13,7 @@ $$ n_e n_h = \frac{1}{2} \left(\frac{k_BT}{\pi\hbar^2}\right)^3
 (m_e^{\ast}m_h^{\ast})^{3/2}e^{-\beta E_{gap}}$$
 
 Charge balance condition:
-$$ D = N_D - N_A$ - n_e + n_h$
+$$ D = N_D - N_A$ - n_e + n_h $$
 
 ### Subquestion 2
  
@@ -34,10 +34,12 @@ Check both cases with lecture notes approximated solutions by doing a Taylor exp
 
 ### Subquestion 1
 
-
+If all the dopants are ionized, the Fermi level gets shifted up towards the conduction band.
 
 ### Subquestion 2
 
+
+
 ### Subquestion 3