Which of the following dopant is NOT used in Ge to obtain n-type semiconductor?

Step-by-step solution

Ge is a Group 14 element. To obtain an n-type semiconductor, Ge must be doped with a pentavalent impurity (Group 15 element) such as P, As, or Sb. Boron (B) is a trivalent impurity (Group 13 element). Doping Ge with B results in a p-type semiconductor. Therefore, B is not used to obtain an n-type semiconductor. Answer: B