Question

When Ge is doped with a pentavalent impurity, the energy required to free the weakly bound electron from the dopant is about:

• A. 0.001 eV
• B. 0.01 eV
• C. 0.72 eV
• D. 1.1 eV

Hint:

In n-type semiconductors, donor electrons require a small energy (~0.01 eV in Ge) to jump into the conduction band.

Answer 1

The Correct Option is B

Doping and Energy Levels in Ge
- Germanium (Ge) is a group IV element, and when doped with a pentavalent impurity (donor), extra free electrons are introduced into the conduction band.
- The energy required to free these donor electrons is very small compared to the band gap of Ge.
- In Ge, this ionization energy is approximately 0.01 eV. Thus, the correct answer is 0.01 eV.