2.5 Performing a literature search for the required constants, draw the room-temperature thermal-equilibrium band diagrams for the following heterojunctions and calculate the values of the built-in potential and the width of the depletion region. Indicate the sources used in extracting the required constants:
a. Si-doped Al0.3Ga0.7As/undoped GaAs, while the dopant distribution is uniform with a concentration equal to 10^16 cm^-3.
b. Si-doped GaAs/undoped In0.2Ga0.8As, while the dopant distribution is uniform with a concentration equal to 10^16 cm^-3.
c. B-doped Si0.8Ge0.2/P-doped Ge, while both dopant distributions are uniform. Boron concentration is equal to 10^17 cm^-3, and the phosphorus concentration is 10^15 cm^-3. Assume all dopants activated and the interface to be ideal with no strain. Use Vegard's law wherever needed.