Comparison Table: P Type vs N Type Semiconductor Properties
Understanding the Difference Between P Type And N Type Semiconductor is crucial for exams, as these concepts form the foundation of electronic devices and circuits in Physics and Engineering. Comparing their properties helps in analyzing devices like diodes and transistors, which are frequently asked in JEE and NEET exams.
Definition of P Type Semiconductor
A P type semiconductor is formed by doping an intrinsic semiconductor, such as silicon, with trivalent impurities like boron or aluminium. This process creates holes as the major charge carriers within the material.
Due to the presence of trivalent dopants, the number of holes exceeds electrons, making holes the majority carriers and electrons the minority carriers in a P type material. Related details can be linked with the Difference Between Circular And Rotational Motion page for conceptual clarity.
Definition of N Type Semiconductor
An N type semiconductor is formed by doping a pure semiconductor, like silicon, with a pentavalent impurity such as phosphorus or arsenic. This introduces excess electrons in the structure.
In N type semiconductors, electrons act as the majority charge carriers, while holes are present in a much lower concentration. This enhances the material’s electrical conductivity. Explore related comparisons at Difference Between Analog And Digital.
Difference Table
| P Type Semiconductor | N Type Semiconductor |
|---|---|
| Doped with trivalent impurities (e.g., Boron) | Doped with pentavalent impurities (e.g., Phosphorus) |
| Majority charge carriers are holes | Majority charge carriers are electrons |
| Holes carry positive charge | Electrons carry negative charge |
| Fermi level is closer to the valence band | Fermi level is closer to the conduction band |
| Minority charge carriers are electrons | Minority charge carriers are holes |
| Electrical conduction is mainly by holes | Electrical conduction is mainly by electrons |
| Created using Group III elements | Created using Group V elements |
| Acceptor atoms generate vacancies (holes) | Donor atoms release extra electrons |
| Example: Silicon with Boron | Example: Silicon with Phosphorus |
| Lower conductivity than N type for same doping | Higher conductivity than P type for same doping |
| Valence band accepts electrons, creating holes | Conduction band receives donated electrons |
| Mobility of holes is less than electrons | Mobility of electrons is higher |
| Colorless or pink in appearance | Colorless or bluish in appearance |
| Symbolized as ‘p’ in circuit diagrams | Symbolized as ‘n’ in circuit diagrams |
| Used in solar cells, LED p-layers | Used in solar cells, LED n-layers |
| Acts as anode in PN junction | Acts as cathode in PN junction |
| Electrons move from P to N region when forward biased | Electrons move from N to P region when forward biased |
| Holes move from P to N region in junction | Electrons move from N to P region in junction |
| Requires less ionization energy for holes | Requires less ionization energy for electrons |
| Common in p-type MOSFETs | Common in n-type MOSFETs |
Key Differences
- P type uses trivalent, N type uses pentavalent dopant
- P type majority carriers are holes, N type are electrons
- Fermi level lies closer to valence in P, conduction in N
- P type conduction due to holes, N type due to electrons
- P type created with Group III, N type with Group V elements
Examples
A typical P type semiconductor is silicon doped with boron, where boron atoms create holes as charge carriers. For an N type example, silicon doped with phosphorus introduces extra electrons for conduction, which is fundamental for diodes and transistors.
Such examples are often linked to electronic device explanations, similar to those found in Difference Between Ohmic And Non-Ohmic Conductors.
Applications
- P type and N type layers in diodes and transistors
- Solar cells require both P and N type regions
- Integrated circuits use both types for logic gates
- LEDs consist of both P type and N type sections
- Rectifiers in power supplies use PN junctions
One-Line Summary
In simple words, P type semiconductor has holes as majority carriers, whereas N type semiconductor has electrons as majority carriers.
FAQs on Difference Between P Type and N Type Semiconductors
1. What is the difference between P-type and N-type semiconductors?
P-type and N-type semiconductors differ primarily in the type of charge carriers that facilitate electrical conduction:
- P-type semiconductors have holes (positive charge carriers) created by adding trivalent impurities (like boron) to pure silicon.
- N-type semiconductors contain free electrons (negative charge carriers) introduced by adding pentavalent impurities (like phosphorus).
- P-type: Majority carriers – holes; Minority carriers – electrons.
- N-type: Majority carriers – electrons; Minority carriers – holes.
2. How are P-type semiconductors formed?
P-type semiconductors are formed when a small amount of trivalent impurity (such as boron, aluminium, or gallium) is added to pure silicon or germanium. This creates more holes than electrons in the crystal lattice.
- Trivalent atoms have 3 valence electrons.
- One valence electron less means a hole is created.
- Holes act as majority charge carriers.
- This process is called acceptor doping.
3. What is the main characteristic of an N-type semiconductor?
N-type semiconductors are characterised by an abundance of free electrons generated by adding pentavalent impurities (like phosphorus, arsenic, or antimony) to pure silicon or germanium.
- Electrons are the majority charge carriers.
- Doping process is called donor doping.
- Pentavalent atoms provide an extra electron.
- This increases electrical conductivity.
4. What are the applications of P-type and N-type semiconductors?
P-type and N-type semiconductors are essential components in modern electronics:
- PN junction diodes: Made by combining P-type and N-type materials, used in rectifiers.
- Transistors: Utilize layers of P-type and N-type semiconductors (like NPN and PNP).
- LEDs and Solar Cells: Use the properties of both types for light emission and energy conversion.
- Integrated circuits (ICs): Contain millions of P-type and N-type regions.
5. What is the role of majority and minority charge carriers in P-type and N-type semiconductors?
In P-type semiconductors, holes act as majority carriers and electrons as minority carriers, while in N-type semiconductors, electrons are majority carriers and holes are minority carriers.
- Majority carriers facilitate most electrical conduction.
- Minority carriers contribute less to conduction but are crucial during phenomena like PN junction operation.
6. Why is the electrical conductivity different in P-type and N-type semiconductors?
The electrical conductivity varies because P-type semiconductors rely on hole movement while N-type semiconductors depend on free electron movement.
- N-type conductivity is typically higher, as electrons have higher mobility than holes.
- Difference in carrier mobility affects the ease with which current flows.
7. How is doping used to create P-type and N-type semiconductors?
Doping is the process of adding specific impurities to pure (intrinsic) semiconductors to increase conductivity.
- P-type: Add trivalent impurities (3 valence electrons) to create holes.
- N-type: Add pentavalent impurities (5 valence electrons) to add free electrons.
- This controls the type and number of charge carriers.
8. What are some common impurities added to make N-type and P-type semiconductors?
Specific elements are chosen for doping to create N-type and P-type semiconductors:
- N-type: Phosphorus (P), Arsenic (As), Antimony (Sb)
- P-type: Boron (B), Aluminium (Al), Gallium (Ga)
These impurities are called donors (for N-type) and acceptors (for P-type).
9. How does a PN junction form and what is its importance?
A PN junction is formed by joining P-type and N-type semiconductors together, which is fundamental in electronics.
- At the junction, electrons from N-type diffuse to the P-type region and recombine with holes.
- This results in the formation of a depletion region with no free charge carriers.
- PN junctions are essential for diodes, solar cells, LEDs, and transistors.
10. State two differences between P-type and N-type semiconductors.
P-type and N-type semiconductors differ in the following ways:
- P-type has holes as majority carriers; N-type has electrons as majority carriers.
- P-type is formed by adding trivalent impurities; N-type by pentavalent impurities.
11. Why are electrons the majority carriers in N-type semiconductors?
In N-type semiconductors, pentavalent impurities (like phosphorus) are added, supplying extra electrons that serve as the majority charge carriers required for conduction.
