X-Git-Url: https://www.hackdaworld.org/gitweb/?a=blobdiff_plain;f=solid_state_physics%2Ftutorial%2F1_06s.tex;h=4e965e31368b9f3353ef8b25dc84beb491688101;hb=6c4e0f74452033badf606ba05abc9c77b2331566;hp=f3d699245dd17b1ce1038f7576de916a868cb5e6;hpb=6d283effbe3004ef67ebae4a627ca228dcd8ad4c;p=lectures%2Flatex.git

diff --git a/solid_state_physics/tutorial/1_06s.tex b/solid_state_physics/tutorial/1_06s.tex
index f3d6992..4e965e3 100644
--- a/solid_state_physics/tutorial/1_06s.tex
+++ b/solid_state_physics/tutorial/1_06s.tex
@@ -51,11 +51,19 @@
 	        =\ldots=5.97 \cdot 10^{-28} \, kg\frac{m}{s}$
        \end{itemize}
  \item Phonon momentum necessary for transition:\\
-       $p=\hbar \cdot \Delta k=\hbar \cdot 0.85 \, \frac{2\pi}{a}
+       $\Delta p=\hbar \cdot \Delta k=\hbar \cdot 0.85 \, \frac{2\pi}{a}
          =\frac{0.85 \, h}{a}=\ldots=1.04 \cdot 10^{-24} \, kg\frac{m}{s}$\\
        $\rightarrow$ Phonon momentum 3 orders of magnitude below
                      the momentum necessary for transition!
- \item 
+ \item \begin{itemize}
+        \item Photon momentum insufficient.
+              Momentum contribution of phonon (lattice vibration) required.\\
+              $\Rightarrow$ Probability of transition very small.
+	\item Recombination energy of electron-hole pairs most probably
+	      released as vibrational energy of the lattice.\\
+	      $\Rightarrow$ Only direct band gap semiconductors suitable for
+	                    effective photon generation.
+       \end{itemize}
 \end{enumerate}
 
 \section{\ldots}