COMEDK · Physics · 30. Semiconductors
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than \(1.24 \mu \mathrm{~m}\) is incident on it. The band gap (in eV ) for the semiconductor is
- A 2.48 eV
- B 1 eV
- C 1.1 eV
- D 0.7 eV
Answer & Solution
Correct Answer
(B) 1 eV
Step-by-step Solution
Detailed explanation
Conductivity increases when photon energy \(\geq\) band gap energy \(E_g\). The threshold wavelength \(\lambda = 1.24\ \mu m\) gives the minimum photon energy equal to \(E_g\). Using \(E(\text{in eV}) = \dfrac{1.24}{\lambda(\text{in } \mu m)}\): \(E_g = \dfrac{1.24}{1.24} = 1\)…
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