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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 1019 m -3 and their mobility is 1.6 m2 / (V.s) then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored ) is close to :

  • Option 1)

    2\Omega m\: \:

  • Option 2)

    4\Omega m\: \:

  • Option 3)

    0.4\Omega m\: \:

  • Option 4)

    0.2\Omega m\: \:

Answers (1)

best_answer

 

Electrical Conductivity (σ) -

\sigma =e \left (n_{e}\mu _{e}+n_{h}\mu _{h} \right )
 

- wherein

n_{e}= electron \: density

n_{h}= hole \: density

\mu _{e}= mobility \: of \: electron

\mu _{h}= mobility \: of \: holes

For intrinsic semiconductors (no impurities), the number of electrons will be equal to the number of holes. 

So  n_{e}=n_{h}=n_{i} 

 \sigma =n_{i}e (\mu _{e}+ \mu _{h} )

 

For N-type semiconductor electrons are majority carriers .

Conductivity \sigma \approx ne \mu

Resistivity \rho = \frac{1}{\sigma} = \frac{1}{n_{e}e \mu}

= \frac{1}{10^{19} \times 1.6 \times \times 10^{-19} \times 1.6 }

= 0.4 \Omega m


Option 1)

2\Omega m\: \:

Option 2)

4\Omega m\: \:

Option 3)

0.4\Omega m\: \:

Option 4)

0.2\Omega m\: \:

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