13.1.1 Understanding intrinsic and extrinsic semiconductors

• The lowest unoccupied energy level in intrinsic semiconductors is called the conduction band.
• In intrinsic semiconductors, the number of electrons and holes is equal.
• N-type semiconductors are formed by doping with elements that have extra valence electrons.
• Electrons are the majority carriers in n-type semiconductors.

  True
• Intrinsic semiconductors have an equal number of electrons and holes in their crystal lattice.


  True
• What is the highest occupied energy level in intrinsic semiconductors called?

  Valence band
• Match the material type with its energy band characteristics:

  Insulator ↔️ Large energy gap

  Semiconductor ↔️ Small energy gap

  Conductor ↔️ No energy gap
• What is the primary process of charge carrier generation in intrinsic semiconductors?

  Thermal excitation
• What is the process called that creates extrinsic semiconductors?

  Doping
• Holes are the majority carriers in p-type semiconductors.
• Which element is commonly used as a dopant in N-type semiconductors?

  Phosphorus
• P-type semiconductors are formed by doping with elements that have fewer valence electrons
• Intrinsic semiconductors have an equal number of electrons and holes in their crystal lattice.

  True
• In intrinsic semiconductors, charge carriers are generated primarily via thermal excitation
• Increasing the temperature of an intrinsic semiconductor increases both electron and hole concentrations.


  True
• Match the property with the type of semiconductor:

  Donor impurities ↔️ N-type

  Acceptor impurities ↔️ P-type
• In p-type semiconductors, holes are the majority charge carriers.


  True
• Steps of the doping process for creating n-type semiconductors

  1️⃣ Add donor impurities to an intrinsic semiconductor

  2️⃣ Extra electrons are added to the conduction band

  3️⃣ Electrons become the majority carriers

  4️⃣ Electron conductivity increases
• Match the semiconductor type with its majority carrier and concentration:

  Intrinsic ↔️ Electrons and Holes (Equal)

  N-type ↔️ Electrons >> Holes

  P-type ↔️ Holes >> Electrons
• What is the process called that modifies the electrical properties of an intrinsic semiconductor by adding impurities?

  Doping
• Electrons are the majority carriers in N-type semiconductors.


  True
• How does temperature affect the conductivity of intrinsic semiconductors?

  Increases conductivity
• The energy gap in semiconductors is larger than in insulators.

  False
• What maintains electrical neutrality in intrinsic semiconductors?

  Equal electrons and holes
• How are extrinsic semiconductors created?

  By doping
• P-type semiconductors have electrons as the majority carriers.

  False
• What type of impurities are added to create n-type semiconductors?

  Donor impurities
• Match the property with the correct semiconductor type:

  Majority Carrier in N-type ↔️ Electrons

  Majority Carrier in P-type ↔️ Holes

  Dopant in N-type ↔️ Phosphorus

  Dopant in P-type ↔️ Boron
• P-type semiconductors increase conductivity by creating holes in the valence band.

  True
• In p-type semiconductors, acceptor impurities create holes
• Intrinsic semiconductors have low conductivity at room temperature
• Match the material type with its energy band properties:

  Insulator ↔️ Large energy gap

  Semiconductor ↔️ Small energy gap

  Conductor ↔️ No energy gap
• What type of dopant is used to create n-type semiconductors?

  Phosphorus
• P-type semiconductors are formed by doping with elements that have fewer valence electrons
• N-type semiconductors are formed by doping with elements like phosphorus
• What is the primary difference in charge carrier concentrations between intrinsic and extrinsic semiconductors?

  Extrinsic semiconductors are doped
• What is the highest occupied energy level in intrinsic semiconductors called?

  Valence band
• In intrinsic semiconductors, charge carriers are generated primarily via thermal excitation
• P-type semiconductors are formed by doping with elements that have fewer valence electrons
• What is the process called that creates extrinsic semiconductors?

  Doping