Update 14_doping_and_devices_solutions.md

src/14_doping_and_devices_solutions.md

@@ -3,7 +3,7 @@ from matplotlib import pyplot as plt
 import numpy as np
 from math import pi
 ```
-# Solutions for lecture 13 exercises
+# Solutions for lecture 14 exercises
 
 ## Exercise 1: Crossover between extrinsic and intrinsic regimes