A photodiode is fabricated from a semiconductor with band gap of 2.8 eV. Cn it detect a wavelength of 6000 nm ? Justify
Asked by vinitapahel123 | 1st Dec, 2015, 03:54: PM
Energy band gap of photodiode, Eg = 2.8 eV
Wavelength, λ = 600 nm = 6000 × 10-9 m
The energy of a signal is given by:
where, h = Planck's constant = 6.626 × 10-34 Js
c = Speed of light = 3 × 108 m/s
The energy (E) of a signal of wavelength 6000 nm is 0.207 eV, which is less than 2.8 eV i.e, the energy band gap of a photodiode.
E < Eg.
Hence, the photodiode cannot detect the radiation of the given wavelength 6000 nm.
Answered by Faiza Lambe | 1st Dec, 2015, 04:25: PM
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