Three photo diodes D1, D2, D3 are made up of semiconductors having band gap of 2 5 eV, 2 eV - Physics - Semiconductor Electronics Materials Devices And Simple Circuits

Question

Three photo diodes D1, D2, D3 are made up of semiconductors having
band gap of 2 5 eV, 2 eV and 3eV respectively Ehich one will be
able to detect light of wavelength 6000 A?

Vijaya Nittala · Accepted Answer

λmax1=hcE=6 6×10-34×3×1082×1
6×10-19=6 18×10-7 mλmax2=hcE=6
6×10-34×3×1082 5×1 6×10-19=3
96×10-7 mλmax3=hcE=6
6×10-34×3×1083×1 6×10-19=4
125×10-7 m
Given λ=6000A=6×10-7 m
For detection of optical signal the wavelength of incident energy
radiation must be greater It is true only for D2 Only D2 can detect
the radiation

Three photo diodes D1, D2, D3 are made up of semiconductors having band gap of 2.5 eV, 2 eV and 3eV respectively. Ehich one will be able to detect light of wavelength 6000 A?