For each of the following semiconductors, sketch the energy band diagrams:
a. Indium phosphide ( \( \ln P \) ), \( E_{g}=1.35 \mathrm{eV}, x=4.4 \mathrm{eV} \);
b. Germanium \( (\mathrm{Ge}), E_{g}=0.67 \mathrm{eV}, x=4.0 \mathrm{eV} \);
c. Gallium nitride \( (\mathrm{GaN}), E_{g}=3.437 \mathrm{eV}, x=4.1 \mathrm{eV} \);
d. Amorphous silicon dioxide \( \left(\mathrm{SiO}_{2}\right), E_{g}=9 \mathrm{eV}, x=0.9 \mathrm{eV} \).