Doping silicon or germanium with a trivalent impurity produces which semiconductor?

1. A trivalent atom has one fewer valence electron than silicon. 2. The missing electron leaves a hole behind. 3. This is obtained when Si or Ge is doped with a trivalent impurity. 4. That gives a p-type semiconductor. _Source: syllabus Physics Part II, Ch 14 'Semiconductor Electronics'_