Three photodiodes D1, D2 and D3 are made of semiconductors having band gaps of 2.5 eV, 2 eV and 3 eV respectively. which of them will not able to detect light of wavelength 600 NM

Asked by vk335548 | 5th Mar, 2019, 10:32: PM

Expert Answer:

Max wavelength 1 = hc/E= 6.6 x 10⁻³⁴ x 3 x 10⁸/ 2 x 1.6 x 10⁻¹⁹= 6.18 x 10⁻⁷ m
max wavelength 2 = hc/E= 6.6 x 10⁻³⁴ x 3 x 10⁸/ 2.5 x 1.6 x 10⁻¹⁹= 3.96 x 10⁻⁷m
max wavelength 3 = hc/E= 6.6 x 10⁻³⁴ x 3 x 10⁸/ 3 x 1.6 x 10⁻¹⁹= 4.125 x 10⁻⁷m
as given A= 6 x 10⁻⁷mThe wave length on incident energy radiation must be greater for optical signals. which is true in case of D2

Answered by Ankit K | 6th Mar, 2019, 10:37: AM