Semiconductors and Doping Quiz

How many valence electrons are there in Si?

• 3

• 14

• 4

• 2

Name the bonding in Si.

• Ionic bond.

• Covalent bond

• Metallic bond

• • Hydrogen bond.

Differentiate p-type and n-type types, explain doping effects, and create energy band diagrams for each.

• p-type: doped with donors, adds holes; n-type: doped with acceptors, creates electrons.
• p-type: has a Fermi level near conduction band; n-type: has a Fermi level near valence band.
• p-type: doped with acceptors (e.g., Boron), creates holes; n-type: doped with donors (e.g., Phosphorus), adds electrons. Energy band diagrams show p-type with Fermi level near valence band and n-type with Fermi level near conduction band.
• p-type: creates electrons; n-type: creates holes.

How can we increase the conductivity of semiconductors?

• Doping with impurities, increasing temperature, or applying an electric field.
• Applying a magnetic field
• Cooling the semiconductor
• Using pure silicon only

A semiconductor in its purest form is called.......

• Insulator

• Superconductor

• Intrinsic semiconductor

• Extrinsic semiconductor

A P-type semiconductor results when…..

• A pentavalent impurity is added to an intrinsic semiconductor.

• A trivalent impurity is added to an intrinsic semiconductor.

• Either a pentavalent or trivalent impurity is added to an intrinsic semiconductor

• None of the above

A doped semiconductor is also known as

• Intrinsic semiconductor

• Extrinsic semiconductor

• Diffused semiconductor

• None of the above

In a N-type semiconductor, the donor level

• Is at the Centre of the energy gap

• Is lower than the Centre of energy gap

• Is higher than the Centre of energy gap

• Can be anywhere depending upon the doping concentration