What is the minimum wavelength of radiation required to detect a p-n junction diode made of a semiconductor having band gap 3.3 eV. [Planck's constant h = 6.6 10³⁴ J.s ]

Step-by-step solution

For a p-n junction diode to detect radiation, the energy of the incident photon must be greater than or equal to the band gap energy of the semiconductor. E E_g hc E_g hc E_g The threshold wavelength is given by: = hc E_g Substituting the standard values: = 6.6 10⁻³⁴ 3 10^8 3.3 1.6 10⁻¹⁹ = 19.8 10⁻²⁶ 5.28 10⁻¹⁹ = 3.75 10⁻⁷ m = 3750 Å Answer: 3750 Å