Applied Physics Unit 1,2 & 3

Which of the following is an example of a semiconductor material?

• Copper
• Gold
• Aluminum
• Silicon

Which of the following properties is true for semiconductors?

• Semiconductors are perfect insulators.
• 1. Their resistance decreases with temperature.

• Semiconductors can only conduct electricity at absolute zero.
• Semiconductors cannot be used in electronic devices.

The energy gap of silicon is approximately:

• 1.1 eV
• 1.5 eV
• 2.0 eV
• 0.5 eV

In semiconductors, current conduction is due to:

• The movement of magnetic fields.
• The vibration of atoms in the lattice.
• The movement of electrons and holes.
• The flow of protons and neutrons.

An intrinsic semiconductor is:

• A semiconductor with controlled impurities.
• A material that conducts electricity poorly.
• A compound semiconductor made of multiple elements.
• A pure semiconductor material with no impurities.

Which impurity is added to silicon to form an N-type semiconductor?

• Boron
• Gallium
• Arsenic
• Phosphorus

In a P-type semiconductor, the majority charge carriers are:

• holes
• protons
• neutrons
• electrons

Which of the following is true for extrinsic semiconductors?

• Extrinsic semiconductors have enhanced conductivity due to doping with impurities.
• Extrinsic semiconductors do not conduct electricity under any circumstances.
• Extrinsic semiconductors are made entirely of pure silicon without any impurities.
• Extrinsic semiconductors have lower conductivity than intrinsic semiconductors.

At the junction of a PN diode, a depletion region is formed due to:

• The presence of impurities in the semiconductor material.
• The application of an external voltage to the diode.
• The diffusion of charge carriers (electrons and holes) leading to recombination.
• The generation of thermal energy within the diode.

The potential barrier for a silicon diode is approximately:

• 0.3 volts
• 1.2 volts
• 0.7 volts
• 0.5 volts