The electrical conductivity of a semiconductor increases when electromagnetic radiation of a wavelength shorter than 2480 nm is incident on it. The bandgap (in eV ) for the semiconductor is

Question

The electrical conductivity of a semiconductor increases when electromagnetic radiation of a wavelength shorter than 2480 nm is incident on it. The bandgap (in eV ) for the semiconductor is (A) 0.9 (B) 0.7 (C) 0.5 (D) 0.1

Tardigrade Admin · Accepted Answer

Band gap is the energy gap between conduction and valence band <img class="img-fluid question-image" alt="Solution" src="https://cdn.tardigrade.in/q/nta/p-kfgw42rb0nhx1af0.jpg" /> For excitation of e- from valence band to conduction band Ephton≥ Eg (hC/λ )≥ Eg ( textE) textg = ( text1240 texteV/λ text(nm)) textE textg = ( text1240 eV/ text2480 ) = text0.5 texteV

Q. The electrical conductivity of a semiconductor increases when electromagnetic radiation of a wavelength shorter than $2480 nm$ is incident on it. The bandgap (in $e V$ ) for the semiconductor is

$0.9$

$0.7$

$0.5$

$0.1$

Band gap is the energy gap between conduction and valence band

For excitation of $e^{-}$ from valence band to conduction band
$E_{p h t o n} \geq E_{g}$
$\frac{h C}{λ} \geq E_{g}$
$(E)_{g} = \frac{1240 eV}{λ (nm)}$
$E_{g} = \frac{1240 eV}{2480} = 0.5 eV$

Q. The electrical conductivity of a semiconductor increases when electromagnetic radiation of a wavelength shorter than 2480nm is incident on it. The bandgap (in eV ) for the semiconductor is

0.9

0.7

0.5

0.1