By doping Germanium with Gallium, the types of semi-conductors formed are:

1. N-type

2. P-type

3. Intrinsic

4. Extrinsic

Which of the above are correct?

• Extrinsic p-Type Semiconductor is formed when a trivalent impurity is added to a pure semiconductor
•  By doping Germanium with Gallium, the types of semi-conductors formed are
• Example of trivalent impurity are Boron, Gallium, and Indium
• Trivalent impurity like boron, have 3 valence electrons
• Each atom of the impurity fits in the silicon crystal by forming covalent bonds with the surrounding silicon atoms
• The dopant boron atom has one less electron than surrounding silicon and thus vacancy is generated that acts as a hole.

This is explained with the help of the following atomic model:

∴ By doping Germanium with Gallium, the types of semi-conductors formed are both extrinsic and p-type.