Density of electrons in an n-type semiconductor is $10^{19} m^{-3}$. If the drift velocity is 0.02 mm/s, when an electric field $1.33 × 10^{-5}V/m$ is applied. Find the resistivity of semiconductor [contribution of holes is ignored]
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 0.4 Ωm
To calculate the Resistivity of n-type semiconductor -
(Resistivity) $ρ = \frac{1}{neμ}$
$μ$ = Mobility of electrons
$n$ = Electron Density
Also,
Drift Velocity, $v_d=μE$
$⇒μ=\frac{v_d}{E}=\frac{0.02×10^{-3}m/s}{1.33×10^{-5}V/m}=1.5×10^{-3}m^2/V.s$
$∴ρ =\frac{1}{(10^{19}m^{-3})×(1.6×10^{-19}C)×(1.5×10^{-3})}$
$=0.4Ωm$