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Consider a situation in which reverse biased current of a particular P-N junction increases when it is exposed to a light of wavelength ≤ 621 nm. During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly:
- 2 eV
- 4 eV
- 1 eV
- 0.5 eV
Correct answer: 2 eV
Solution
The threshold wavelength corresponds to the band gap: Eg = hc/lambda = 1240 (eV.nm)/621 nm ~ 2.0 eV. So the band gap is nearly 2 eV.
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