Three photodiodes D1, D2 and D3 are made of semiconductors having band gaps of 2.5eV, 2eV and 3eV, respectively. Which ones will be able to detect light of wavelength 6000 Å?
Hint: To detect radiation, its energy should be more than that of the energy bandgap.
Step 2: Find the energy of the radiation.
Given, the wavelength of light
The energy of the light photon:
Step 2: Compare the radiation energy with the energy of the bandgap.
The incident radiation which is detected by the photodiode having energy should be greater than the band-gap. So, it is only valid for diode D2. Then, diode D2 will detect this radiation.
