The intrinsic carrier concentration in silicon at T = 300 K is known to be n i = 1 . 5 × 10 16 m - 3 . A sample of silicon is doped with 5 × 10 22 m - 3 arsenic (a group V element). Under these circumstances the concentrations of electrons ( n ) and holes ( p ) in the sample are

n = 5 × 10 22 m - 3 , p = 4 . 5 × 10 9 m - 3

n = 1 . 5 × 10 22 m - 3 , p = 0 . 5 × 10 9 m - 3

n = 1 . 5 × 10 16 m - 3 , p = 1 . 5 × 10 16 m - 3

n = 4 . 5 × 10 9 m - 3 , p = 5 × 10 22 m - 3

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In a pure semiconductor crystal, if current flows due to breakage of crystal bonds, then what is the semiconductor is called?

Important Questions on Semiconductor Electronics: Materials, Devices and Simple Circuits

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

In an unbiased p - n junction electrons diffuse from n-region to p-region because:

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an

N

-type semiconductor, the density of electrons is

10^{19} m^{- 3}

and their mobility is

1.6 m^{2} V^{- 1} s^{- 1}

, then the resistivity of the semiconductor (since it is an

N

-type semiconductor contribution of holes is ignored) is close to:

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

$G e$ and $S i$ diodes start conducting at $0.3 V$ and $0.7 V$ respectively. In the following figure if $G e$ diode connection are reversed, the value of $V_{0}$ changes by: (assume that the Ge diode has large breakdown voltage)

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

The given circuit has two ideal diodes connected as shown in the figure below. The current flowing through the resistance $R_{1}$ will be

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

n -

type semiconductor contains:

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

The forward biased diode connection is :

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

Consider the junction diode as ideal. The value of current flowing through AB is:
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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

Identify the semiconductor devices whose characteristics are given below, in the order $(a), (b), (c), (d)$ :

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

What are the majority and minority carriers in a p-type semiconductors

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

Intrinsic carrier concentration of a silicon sample at

300 K

1.5 \times 10^{16} m^{- 3} .

After doping, the number of majority carriers is

2.25 \times 10^{20} m^{- 3} .

The minority carrier density is

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

The $V - I$ characteristic of a diode is shown in the figure. The ratio of forward to reverse bias resistance is:

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

A semiconductor has equal electron and hole concentration

6 \times 10^{8} m^{- 3}

. On doping with a certain impurity electron concentration increases to

9 \times 10^{12} m^{- 3}

. Calculate the new hole concentration. Also identify the new semiconductor.

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

Which one of the following represents forward bias diode?

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

2 V

battery is connected across

A B

as shown in the figure. The value of the current supplied by the battery when in first case battery's positive terminal is connected to

A

and in second case when positive terminal of battery is connected to

B

will respectively be:
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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

The reading of the ammeter for a silicon diode in the given circuit is:

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

The barrier potential of a p-n junction depends on:

(a)

type of semi-conductor material

(b)

amount of doping

(c)

temperature
Which one of the following is correct?

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

Both the diodes used in the circuit shown are assumed to be ideal and have negligible resistance when these are forward biased. Built in potential in each diode is

0.7 V

. For the input voltages shown in the figure, the voltage (in Volts) at point A is ________
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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

The intrinsic carrier concentration in silicon at

T = 300 K

is known to be

n_{i} = 1.5 \times 10^{16} m^{- 3}

. A sample of silicon is doped with

5 \times 10^{22} m^{- 3}

arsenic (a group

V

element). Under these circumstances the concentrations of electrons

(n)

and holes

(p)

in the sample are

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

When indium is doped to silicon as impurity, the resulting material is

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Physics>Modern Physics>Semiconductor Electronics: Materials, Devices and Simple Circuits>p-n Junction and Semiconductor Diode

The density of an electron-hole pair in pure germanium is

3 \times 10^{16} m^{- 3}

at room temperature. On doping with aluminium, the hole density increases to

4.5 \times 10^{22} m^{- 3}

. Now the electron density (in

m^{- 3}

) in doped germanium will be

In a pure semiconductor crystal, if current flows due to breakage of crystal bonds, then what is the semiconductor is called?

Important Questions on Semiconductor Electronics: Materials, Devices and Simple Circuits

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