EASY

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What will happen if we increase temperature in an intrinsic semiconductor ?

Important Questions on Electronic Devices

MEDIUM

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

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

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

Which of the following statements is incorrect?

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

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

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

In a semiconductor, the concentration of minority carriers depends mainly on

HARD

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

With reference to semi-conductors answer the following

:

(i)

What is the change in the resistance of the semi

‐

conductor with increase in temperature?

HARD

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

In a semiconductor, the number density of intrinsic charge carriers at

27 ° C

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

. If the semiconductor is doped with an impurity atom, the hole density increases to

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

. The electron density in the doped semiconductor is _______

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

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

A donor impurity results in

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

In a semiconductor, the conductivity increases with the increase in temperature due to

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

An intrinsic semiconductor is converted into

n

-type extrinsic semiconductor by doping it with:-

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

At a certain temperature, the number density of charge carriers in a semiconductor is

n

. When an electric field is applied to it, the charge carriers drift with an average speed

v

. If the temperature of the semiconductor is raised.

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

An extrinsic semiconductor with electrons as majority carriers can be obtained by doping Ge or Si with

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

For a

p -

type semiconductor, which of the following statements is true?

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

The intrinsic carrier concentration of silicon sample at

300 K

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

What is the density of minority carrier? (after doping, the number of majority carriers is

5 \times 10^{20} / m^{3})

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

For extrinsic semiconductors; when doping level is increased;

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

As the temperature of the semiconductor is increased, the mobility of electrons and holes

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

Statement I: By doping silicon semiconductors with pentavalent material, the electrons density increases.

Statement II: The $n -$ type of semiconductor has a net negative charge.

In the above statements, choose the most appropriate answer from the options given below:

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

The electron concentration in an undefined

n

-type semiconductor is the same as hole concentration in a undefined

p

-type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them.

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

An intrinsic semiconductor is:

EASY

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

The conductivity of semiconductor increases with increase in temperature because

MEDIUM

Physics>Modern Physics>Electronic Devices>Conductors, insulators and Semiconductors

The conductivity of a semiconductor sample having electron concentration of

5 \times 10^{18} electrons m^{- 3}

, hole concentration of

5 \times 10^{19} holes m^{- 3}

, electron mobility of

2 .0 m^{2} V^{- 1} s^{- 1}

and hole mobility of

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

is

(Take charge of an electron as

1 .6 \times 10^{- 19} C

)

What will happen if we increase temperature in an intrinsic semiconductor ?

Important Questions on Electronic Devices

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