Three photodiodes `D_1 , D_2 ` and `D_3` are made of semiconductors ha – InterviewSolution

InterviewSolution

1.	Three photodiodes `D_1 , D_2 ` and `D_3` are made of semiconductors having band gaps of ` 2.5 eV , 2 eV` and 3 eV , respectively . Which one will be able to detect light of wavelength ` 6000 Å ` ?
Answer» Energy of the incident photon, `E=(hc)/lambda=((6.6xx10^(-34))xx(3xx10^(8)))/((6xx10^(-7))xx1.6xx10^(-19))=2.06eV` The incident radiation can be detected by a photodiode if energy of incident radiation photon is greater than the band gap. This is true for `D_(2)(=2eV)`. Therefore, only `D_(2)` will detect these radiations.

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