Update 14_doping_and_devices_solutions.md

src/14_doping_and_devices_solutions.md

@@ -92,7 +92,7 @@ $$ I_s(T) \propto e^{-E_{gap}/k_BT}$$
 ### Subquestion 1
 
 ![](figures/diagram_14.png)
-
+* Include the energy bands here. You can find them at the book's section 18.2 
 
 ### Subquestion 2
 This a "particle in a box" problem.
@@ -114,6 +114,8 @@ $$g_h = \frac{4 \pi m_h^{\ast}}{\hbar^2}$$
 L can be found here for $k_x$ and $k_y$ using previous subquestions.
 Setting $$ E_e - E_h - E_c + E_v = 1 eV = \frac{\hbar^2 (k_x^2+k_y^2)}{2}
 (\frac{1}{m_e^{\ast}}+\frac{1}{m_h^{\ast}})$$
+Taking  $k_x^2+k_y^2=(\frac{\pi}{L})^2$, L can be found as $6.85$ nm approx.
+
 
 ### Subquestion 6