fix a couple of typos

src/14_doping_and_devices.md

@@ -144,7 +144,7 @@ Additional information can be obtained using Hall effect. However Hall effect is
 
 ### Light absorption
 
-See [previous lecture](.md#light-adsorption)
+See [previous lecture](12_band_structures_in_higher_dimensions.md#light-adsorption)
 
 ## Combining semiconductors: $pn$-junction
 
@@ -211,11 +211,11 @@ Density of states in a doped semiconductor:
 fig
 ```
 
-Charge balance determins the number of electrons and holes as well as the position of the Fermi level.
+Charge balance determines the number of electrons and holes as well as the position of the Fermi level.
 
-If dopant concentrations are low, then $n_e = n_h = n_i \equiv \sqrt{N_C N_V}e^{-E_G/2kT}$.
+If dopant concentration is low, then $n_e = n_h = n_i \equiv \sqrt{N_C N_V}e^{-E_G/2kT}$.
 
-If dopant concentrations are high, then in $n$-doped semiconductor $n_e = N_D - N_A$ and $n_h = n_i^2/n_e$ (or vice versa).
+If dopant concentration is high, then in $n$-doped semiconductor $n_e = N_D - N_A$ and $n_h = n_i^2/n_e$ (or vice versa in $p$-doped one).
 
 Temperature switches between intrinsic and extrinsic regimes, and controls the carrier density
 
@@ -248,7 +248,7 @@ For that we consider a doped semiconductor in the extrinsic regime.
 
 ### Exercise 3: Performance of a diode
 
-Consider a pn-junction diode as follows 
+Consider a pn-junction diode as follows
 
 <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/7/79/PN_diode_with_electrical_symbol.svg/800px-PN_diode_with_electrical_symbol.svg.png" width="50%" alt="pn diode"></img>