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Questions and Answers
How does the Fermi level shift in an n-type semiconductor with an increase in temperature?
How does the Fermi level shift in an n-type semiconductor with an increase in temperature?
In an intrinsic semiconductor, how does the Fermi level shift with an increase in temperature?
In an intrinsic semiconductor, how does the Fermi level shift with an increase in temperature?
What causes the potential barrier in a p-n diode?
What causes the potential barrier in a p-n diode?
What happens to the width of the potential barrier in a p-n junction diode under forward bias?
What happens to the width of the potential barrier in a p-n junction diode under forward bias?
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What effect does reversing the polarity of the battery have in a series circuit with a semi-conducting device?
What effect does reversing the polarity of the battery have in a series circuit with a semi-conducting device?
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What is the primary characteristic of a p-type semiconductor?
What is the primary characteristic of a p-type semiconductor?
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What happens to current when a potential barrier is decreased in a p-n junction diode?
What happens to current when a potential barrier is decreased in a p-n junction diode?
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What is the effect of increasing temperature on the drift of charge carriers?
What is the effect of increasing temperature on the drift of charge carriers?
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What is the drift velocity of holes in p-type Germanium when an electric field of 10 V/m is applied?
What is the drift velocity of holes in p-type Germanium when an electric field of 10 V/m is applied?
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Which unit is used to express resistivity?
Which unit is used to express resistivity?
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What is the correct formula for calculating mobility?
What is the correct formula for calculating mobility?
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If minority carriers are injected into a semiconductor and travel a distance of 1 cm in 20 µsec under an electric field of 10 V/cm, what is the mobility in cm²/volt∙sec?
If minority carriers are injected into a semiconductor and travel a distance of 1 cm in 20 µsec under an electric field of 10 V/cm, what is the mobility in cm²/volt∙sec?
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What is the resistance of a wire of length 0.85 m and cross section 2.0 × 10–6 m² if the electrical resistivity is 4.3 × 10–7 Ω·m?
What is the resistance of a wire of length 0.85 m and cross section 2.0 × 10–6 m² if the electrical resistivity is 4.3 × 10–7 Ω·m?
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What is the unit for conductivity?
What is the unit for conductivity?
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In which scenario would the effective mass of an electron be considered negative?
In which scenario would the effective mass of an electron be considered negative?
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What is the mobility of holes in p-type Germanium in cm²/V-s if the drift velocity is 1.7 m/s and the electric field applied is 10 V/m?
What is the mobility of holes in p-type Germanium in cm²/V-s if the drift velocity is 1.7 m/s and the electric field applied is 10 V/m?
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If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, what is the effect on the majority carrier density?
If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, what is the effect on the majority carrier density?
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What primarily causes the current in an intrinsic semiconductor at room temperature?
What primarily causes the current in an intrinsic semiconductor at room temperature?
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Which equation correctly represents the mobility of charge carriers in a semiconductor?
Which equation correctly represents the mobility of charge carriers in a semiconductor?
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In a p-type semiconductor, what formula describes the conductivity due to holes?
In a p-type semiconductor, what formula describes the conductivity due to holes?
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How does resistivity change with an increase in temperature for good conductors?
How does resistivity change with an increase in temperature for good conductors?
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If a semiconductor is transparent to light of wavelength greater than λ, what can be said about its band gap energy?
If a semiconductor is transparent to light of wavelength greater than λ, what can be said about its band gap energy?
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Which statement is true regarding the resistivity of insulators as temperature increases?
Which statement is true regarding the resistivity of insulators as temperature increases?
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What is the effect of increasing temperature on the resistivity of semiconductors?
What is the effect of increasing temperature on the resistivity of semiconductors?
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Which of the following describes a material with a positive temperature coefficient of resistance?
Which of the following describes a material with a positive temperature coefficient of resistance?
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When forward bias is applied to a p-n junction diode, what happens to the Fermi level in n-type material relative to p-type?
When forward bias is applied to a p-n junction diode, what happens to the Fermi level in n-type material relative to p-type?
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What effect does reverse bias have on the Fermi level in n-type material?
What effect does reverse bias have on the Fermi level in n-type material?
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What happens to the width of the depletion layer when forward bias voltage is applied to a p-n junction diode?
What happens to the width of the depletion layer when forward bias voltage is applied to a p-n junction diode?
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The depletion layer in a p-n junction diode opposes the flow of which type of charge carriers?
The depletion layer in a p-n junction diode opposes the flow of which type of charge carriers?
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In a transistor, which part is heavily doped to produce a large number of majority carriers?
In a transistor, which part is heavily doped to produce a large number of majority carriers?
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When a forward biased GaAs diode is used, what type of radiation is primarily emitted?
When a forward biased GaAs diode is used, what type of radiation is primarily emitted?
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When discussing a p-n junction diode, what occurs during the recombination of electron hole pairs?
When discussing a p-n junction diode, what occurs during the recombination of electron hole pairs?
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In a p-n junction diode under reverse bias, which charge carrier predominantly flows?
In a p-n junction diode under reverse bias, which charge carrier predominantly flows?
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What happens to the current in a pn junction diode when the reverse bias is increased to a large value?
What happens to the current in a pn junction diode when the reverse bias is increased to a large value?
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What primarily composes the depletion layer in a pn junction?
What primarily composes the depletion layer in a pn junction?
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In a p-type semiconductor, what charge carriers predominantly increase with a rise in temperature?
In a p-type semiconductor, what charge carriers predominantly increase with a rise in temperature?
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What is the nature of charge carriers in the n-type depletion layer?
What is the nature of charge carriers in the n-type depletion layer?
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What is the potential difference in an unbiased pn junction?
What is the potential difference in an unbiased pn junction?
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What happens to the minority carrier current in a diode when reverse bias is applied?
What happens to the minority carrier current in a diode when reverse bias is applied?
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Why is the electrical resistance of the depletion layer large?
Why is the electrical resistance of the depletion layer large?
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In a forward biased p-n junction, what is the typical order of the current?
In a forward biased p-n junction, what is the typical order of the current?
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What is the approximate positive carrier concentration in sample A at room temperature?
What is the approximate positive carrier concentration in sample A at room temperature?
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What is the density of electrons if the Hall coefficient of a material is $1.25 \times 10^{-11} \ m^3/C$ and the charge of an electron is $1.6 \times 10^{-19} \ C$?
What is the density of electrons if the Hall coefficient of a material is $1.25 \times 10^{-11} \ m^3/C$ and the charge of an electron is $1.6 \times 10^{-19} \ C$?
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The Hall effect is observed when a specimen is carrying current and placed in a magnetic field. The resultant electric field inside the specimen will be in what direction?
The Hall effect is observed when a specimen is carrying current and placed in a magnetic field. The resultant electric field inside the specimen will be in what direction?
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When the electron density (ne) and hole density (nh) are present, when is the Hall coefficient positive?
When the electron density (ne) and hole density (nh) are present, when is the Hall coefficient positive?
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What is the effect known as when an e.m.f. is generated across an open-circuited p-n junction when light is incident on it?
What is the effect known as when an e.m.f. is generated across an open-circuited p-n junction when light is incident on it?
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What type of output does a solar cell provide?
What type of output does a solar cell provide?
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What type of material does a solar cell consist of?
What type of material does a solar cell consist of?
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In the context of carrier mobilities, which of the following conditions is correct for the Hall coefficient to remain positive?
In the context of carrier mobilities, which of the following conditions is correct for the Hall coefficient to remain positive?
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Study Notes
Solid State Physics Multiple Choice Questions
- Absolute Zero: Silicon acts as an insulator at absolute zero.
- Valence Electrons: Carbon, silicon, and germanium atoms have four valence electrons each.
- Energy Band Gap: The forbidden energy gap in insulators is greater than 6 eV. In semiconductors, it's in the range of 1-2 eV.. In insulators, it's 3-4 eV.
- Energy Band Gap Relationships: The energy band gap of carbon (Eg)c is greater than silicon (Eg)si and germanium (Eg)Ge.
- Crystalline Solids: Elements in crystalline solids give rise to a band spectrum.
- Diamond vs Silicon vs Germanium: Diamond > silicon > germanium in terms of band gaps.
- Conduction Band: The conduction band contains free electrons and is above the valence band.
- Forbidden Band: The forbidden band does not contain electrons and is between the valence and conduction bands.
- Valence Band: The valence band contains valence electrons.
- Intrinsic Semiconductor: Examples include silicon (Si) and germanium (Ge).
- Extrinsic Semiconductor: Contains impurities.
- N-type Semiconductor: Doped with elements from group 15 (e.g., phosphorus).
- P-type Semiconductor: Doped with elements from group 13 (e.g., boron).
- Energy Bands in Solids: The arrangement of allowed energy levels in a solid forms energy bands. The formation of energy bands is prominent in solids.
- Energy Band Gap in Silicon: 1.1 eV.
- Energy Band Gap in Germanium: 0.7 eV.
- N-type and P-type N-type semiconductors have excess electrons, while P-type has excess holes.
- Conductivity: The reciprocal of resistivity.
- Resistivity: The resistance of a conductor of unit length and unit cross-section area.
- Temperature and Conductivity: In metals conductivity decreases while in semiconductors it increases.
- Intrinsic vs Extrinsic Semiconductor: Intrinsic semiconductors are pure, while extrinsic are impure.
- Energy Gap: Energy gap changes based on the temperature of the element.
- Mobility The reciprocal of resistivity and rate of movement of either electrons or holes under certain circumstances.
- Electric Field The effect of electrical charges.
- Conduction in Intrinsic Semiconductors: Due to both free electrons and holes.
- Charge Carriers in P-Type: Holes.
- Charge Carriers in N-Type: Free electrons
- P-N Junction: A p-n junction is a boundary between p-type and n-type semiconductors.
- Forward Bias: Current flows from positive to negative end of supply.
- Reverse Bias: No appreciable current flows through junction.
- Depletion Region: The region where the neutral portions meet.
- Forbidden Band: The band that does not have any energy states.
- Hall Effect: A phenomenon that can determine the sign and concentration of charge carriers in a substance
- Solar Cell: A device that converts light energy into electrical energy.
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Description
Test your understanding of semiconductor physics concepts, including the behavior of p-n junctions, Fermi level shifts in n-type and intrinsic semiconductors, and the effects of temperature on charge carriers. This quiz also covers mobility, resistivity, and the effects of electric fields in semiconductor devices.
