13.1.2 Exploring p-n junctions

• Match the type of semiconductor with its majority charge carrier:

  p-type ↔️ Holes

  n-type ↔️ Electrons
• In a p-type semiconductor, Group III elements create an excess of holes
• What acts as a barrier to further diffusion in a p-n junction?

  Built-in potential difference
• What is the process of adding impurities to pure semiconductors to modify their conductivity called?

  Doping
• What type of electrical behavior does a p-type semiconductor exhibit?

  Conducts positive charge
• Semiconductors have electrical properties between conductors and insulators.

  True
• Diffusion in a p-n junction occurs due to differences in charge carrier concentration.


  True
• Match the type of material with its key feature in a band diagram:

  Conductor ↔️ Overlapping valence and conduction bands

  Insulator ↔️ Large gap between valence and conduction bands

  Semiconductor ↔️ Intermediate gap between valence and conduction bands
• The energy difference between the valence band and the conduction band in a semiconductor is called the bandgap.
• What does the built-in potential in a p-n junction oppose?

  Further diffusion
• What is formed when a p-type and an n-type semiconductor are joined?

  p-n junction
• Match the type of biasing with its effect on the depletion region:

  Forward Bias ↔️ Depletion region narrows

  Reverse Bias ↔️ Depletion region widens
• Semiconductors have electrical conductivity between that of conductors and insulators.


  True
• Which group III element is commonly used to dope p-type semiconductors?

  Boron
• In a p-n junction, holes from the p-side move to the n-side
• Steps in the formation of the depletion region

  1️⃣ Diffusion of holes and electrons

  2️⃣ Recombination of charge carriers

  3️⃣ Creation of the depletion region

  4️⃣ Establishment of built-in potential
• The depletion region is devoid of free charge carriers
• Match the bias state with its key features in a p-n junction:

  No Bias ↔️ Flat bands, built-in voltage

  Forward Bias ↔️ Lowered voltage, depletion narrows

  Reverse Bias ↔️ Raised voltage, depletion widens
• Steps for forward biasing a p-n junction

  1️⃣ Apply positive voltage to p-side

  2️⃣ Depletion region narrows

  3️⃣ Current increases exponentially
• Diodes use p-n junctions to rectify AC into DC
• What allows transistors to act as amplifiers in electronic circuits?

  Current control through p-n junctions
• What are semiconductors classified between in terms of electrical properties?

  Conductors and insulators
• What is formed when a p-type and an n-type semiconductor are joined?

  p-n junction
• What is doping used for in semiconductors?

  Modify conductivity
• The depletion region in a p-n junction is devoid of free charge carriers.


  True
• Holes are the majority charge carriers in n-type semiconductors.

  False
• In n-type semiconductors, an excess of electrons serves as the majority charge carriers.
• Steps in the formation of a depletion region in a p-n junction:

  1️⃣ Diffusion of holes and electrons across the junction

  2️⃣ Recombination of holes and electrons

  3️⃣ Creation of a depletion region devoid of free charge carriers

  4️⃣ Establishment of a built-in potential
• Recombination of holes and electrons in a p-n junction leads to the neutralization of charges.
• What happens to the depletion region in a p-n junction under forward bias?

  It shrinks
• In a semiconductor, the two main energy bands are the valence band and the conduction band.
• At the junction of a p-n junction, a depletion region is created, which is devoid of free charge carriers.
• Under reverse bias, the depletion region widens, resulting in a very small saturation current.
• Doping is the process of adding impurities to pure semiconductors to modify their conductivity.
• In n-type semiconductors, Group V elements are added to create an excess of electrons.
• The built-in potential difference opposes further diffusion
• Recombination of holes and electrons results in their neutralization


  True
• Band diagrams illustrate energy levels in semiconductor materials

  True
• How does forward bias affect the depletion region width?

  It narrows it
• Reverse bias results in a small saturation current in a p-n junction


  True