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CBSE Class 12 NCERT Physics Semiconductor Electronics: Materials, Devices and Simple Circuits
Semiconductor Electronics: Materials, Devices and Simple Circuits

In a p-n junction diode, the current I can be expressed as
$I=I_{0} \exp \left(\frac{e V}{2 k_{B} T}-1\right)$
where $I_{0}$ is called the reverse saturation current, $V$ is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, $k_{B}$ is the Boltzmann constant $\left(8.6 \times 10^{-5} \mathrm{eV} / \mathrm{K}\right)$ and $\mathrm{T}$ is the absolute temperature. If for a given diode $\mathrm{l}_{0}=5$ $\times 10^{-12} \mathrm{~A}$ and $\mathrm{T}=300 \mathrm{~K}$, then
(a) What is the dynamic resistance?
(b) What will be the current if reverse bias voltage changes from $1 \mathrm{~V}$ to $2 \mathbf{V}$ ?

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The expression for current in a p-n junction diode, is given as $I=I_{0} \exp \left(\frac{e V}{2 k_{B} T}-1\right)$ Here, $l_{0}=5 \times 10^{-12} \mathrm{~A}$ $\mathrm{T}=300 \mathrm{~K}$...

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In a p-n junction diode, the current I can be expressed as
$I=I_{0} \exp \left(\frac{e V}{2 k_{B} T}-1\right)$
where $I_{0}$ is called the reverse saturation current, $V$ is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, $k_{B}$ is the Boltzmann constant $\left(8.6 \times 10^{-5} \mathrm{eV} / \mathrm{K}\right)$ and $\mathrm{T}$ is the absolute temperature. If for a given diode $\mathrm{l}_{0}=5$ $\times 10^{-12} \mathrm{~A}$ and $\mathrm{T}=300 \mathrm{~K}$, then
(a) What will be the forward current at a forward voltage of $0.6$ V?
(b) What will be the increase in the current if the voltage across the diode is increased to $0.7 \mathrm{~V}$ ?

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The expression for current in a p-n junction diode, is given as $I=I_{0} \exp \left(\frac{e V}{2 k_{B} T}-1\right)$ Here, $l_{0}=5 \times 10^{-12} \mathrm{~A}$ $\mathrm{T}=300 \mathrm{~K}$...

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In an intrinsic semiconductor the energy gap $\mathrm{E}_{\mathrm{g}}$ is $1.2 \mathrm{eV}$. Its hole mobility is much smaller than electron mobility and independent of temperature. What is the ratio between conductivity at $600 \mathrm{~K}$ and that at $300 \mathrm{~K}$ ? Assume that the temperature dependence of intrinsic carrier concentration $n_{i}$ is given by
$n_{i}=n_{0} \exp \left[-\frac{E_{g}}{2 k_{B} T}\right]$
where, $n_{0}$ is constant.

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Energy gap in an intrinsic semiconductor is given as $E_{g}=1.2 \mathrm{eV}$ The temperature dependence of the intrinsic carrier-concentration is given by the relation, $n_{i}=n_{0} \exp...

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The number of silicon atoms per $\mathrm{m}^{3}$ is $5 \times 10^{28} .$ This is doped simultaneously with $\mathbf{5} \times$ $10^{22}$ atoms per $\mathrm{m}^{3}$ of Arsenic and $5 \times 10^{20}$ per $\mathrm{m}^{3}$ atoms of Indium. Calculate the number of electrons and holes.

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Number of silicon atoms is given as $N=5 \times 10^{28}$ atoms $/ \mathrm{m}^{3}$ Number of arsenic atoms is given as $\mathrm{n}_{\mathrm{AS}}=5 \times 10^{22}$ atoms $/ \mathrm{m}^{3}$ Number of...

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In an unbiased p-n junction, holes diffuse to $n-$ region from $p$ – region because
(a) free electrons in the $n$-region attract them.
(b) they move across the junction by the potential difference.
(c) hole concentration in p-region is more as compared to n-region.
(d) All of the above.

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(c) is the correct option. The charge carriers' natural tendency is to disperse from the greater concentration zone to the lower concentration region. As a result, holes disperse from the p-region...

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Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separate by energy band gap respectively equal to $\left(E_{g}\right)_{S i},\left(E_{g}\right)_{c}$ and $\left(E_{g}\right)_{G e} .$ Which of the following statements is true?
(a) $\left(E_{g}\right)_{S i}<\left(E_{g}\right)_{G e}<\left(E_{g}\right)_{C}$
(b) $\left(E_{g}\right)_{C}<\left(E_{g}\right)_{G e}>\left(E_{g}\right)_{S i}$
(c) $\left(E_{g}\right)_{C}>\left(E_{g}\right)_{S i}>\left(E_{g}\right)_{G e}$
(d) $\left(E_{g}\right)_{C}=\left(E_{g}\right)_{S i}=\left(E_{g}\right)_{G e}$

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(c) is the correct option. Carbon has the largest energy bandgap among carbon, germanium, and silicon, while germanium has the smallest. The energy band gap can be related as:...

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Which of the statements given is true for $p$-type semiconductors?
(a) Electrons are majority carriers and trivalent atoms are the dopants.
(b) Electrons are minority carriers and pentavalent atoms are the dopants.
(c) Holes are minority carriers and pentavalent atoms are the dopants.
(d) Holes are majority carriers and trivalent atoms are the dopants

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Here, (d) is the correct explanation. The majority carriers in a p-type semiconductor are holes, while the minority carriers are electrons. Trivalent atoms such as aluminium in silicon atoms are...

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In an $\mathrm{n}$-type silicon, which of the following statement is true:
(a) Electrons are majority carriers and trivalent atoms are the dopants.
(b) Electrons are minority carriers and pentavalent atoms are the dopants.
(c) Holes are minority carriers and pentavalent atoms are the dopants.
(d) Holes are majority carriers and trivalent atoms are the dopants.

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Here, (c) is the correct option. The majority carriers in n-type silicon are electrons, while the minority carriers are holes. Dropping pentavalent elements like phosphorus into silicon atoms...

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