Podcast Beta
Questions and Answers
What are III–V compounds commonly used for?
Which of the following is a common material used for light detectors?
What characteristic of a semiconductor determines the wavelengths of light it can absorb or emit?
Which binary compound is often used for light-emitting diodes?
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The band gap of GaAs is approximately how many electron volts?
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Which material is typically used in semiconductor lasers?
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Which compound is known for its use in fluorescent materials used in television screens?
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What is the relationship between energy, wavelength, and the equation provided for photon light?
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What is an elemental semiconductor?
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Which of the following factors can affect the electrical conductivity of semiconductors?
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What type of semiconductor is silicon classified as?
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Which columns in the periodic table primarily contain semiconductor materials?
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What is the significance of crystal growth in semiconductor technology?
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Which of the following methods is involved in semiconductor crystal growth?
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What role does the arrangement of atoms play in semiconductors?
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Which characteristic makes semiconductors preferable for electronic devices?
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Study Notes
Semiconductor Materials
- Semiconductors have electrical conductivity between metals and insulators.
- Conductivity is highly variable due to temperature, light, and impurities. This makes them ideal for electronic devices.
- Found in Group IV and neighboring columns of the periodic table.
- Group IV semiconductors (silicon (Si) and germanium (Ge)) are elemental.
- Compound semiconductors are formed from combinations of elements from Groups III and V, II and VI, and IV.
- Germanium was used early in transistors and diodes; silicon is now dominant in rectifiers, transistors, and integrated circuits (ICs).
- Compound semiconductors are used in high-speed and optoelectronic devices.
- Examples of binary III-V compounds include GaN, GaP, and GaAs (common in light-emitting diodes, or LEDs).
- Ternary (e.g., GaAsP) and quaternary (e.g., InGaAsP) compounds offer greater material property flexibility.
- II-VI compounds (e.g., ZnS) are used in fluorescent materials.
- InSb, CdSe, PbTe, and HgCdTe are used in light detectors.
- Si and Ge are used in infrared and nuclear radiation detectors.
- GaN and other III-V compounds are used in LEDs.
- GaAs, AlGaAs, and other ternary and quaternary compounds are used in semiconductor lasers.
Energy Band Gap
- A key characteristic differentiating semiconductors from metals and insulators.
- Determines the wavelengths of light absorbed or emitted.
- The energy of a photon (E, in eV) and its wavelength (λ, in μm) are related by λ = 1.24/E.
- GaAs has a band gap of ~1.43 eV (near-infrared light).
- GaP has a band gap of ~2.3 eV (green light).
- A table of band gaps and other properties for various semiconductors is available in Appendix III (not shown here).
- The variation in band gaps allows LEDs and lasers to be built with wavelengths across a wide range of the infrared and visible spectrum.
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Description
This quiz covers the essential concepts of semiconductor materials, focusing on their conductivity, types, and applications. Explore the differences between elemental and compound semiconductors along with specific examples used in electronics. Perfect for students in materials science or electronics courses.
