The resistivity of a uniformly doped n-type silicon sample is 0.50 Ω-cm. If the electron mobility (μn) is 1250 cm2/V-sec and the charge of an electron is 1.6 × 10-19 coulomb, the donor impurity concentration (ND) in the sample is

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UPSC ESE (Prelims) Electronics and Telecommunication Engineering 19 Feb 2023 Official Paper
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  1. 2 × 1016/cm3
  2. 1 × 1016/cm3
  3. 2.5 × 1015/cm3
  4. 2 × 1015/cm3

Answer (Detailed Solution Below)

Option 2 : 1 × 1016/cm3
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Given that,

n = 0.50 \(\Omega\)-cm

Electron mobility(\(\mu_n\)) = 1250 cm2/V-sec.

Electron charge(eq) = \(1.6\times 10^-19\)

ND = ?

\(\sigma = \frac{1}{e} = nq\mu n\)

\(n = N_D \frac{1}{eq\mu n}\)

\(\frac{1}{0.5\times1.6\times10^-19\times1250}\)

\(1\times 10\)-16 /cm3

Here, option 2 is correct.

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