Engineering Physics

Solved Problems

1.    A semiconductor diode laser has a peak emission wavelength of 1.55 μm. Find its band gap in eV.

 

(Set-2–May 2008)

Sol: Energy gap of semiconductor, E_g = energy of emitted photon, hν

where c = velocity of light = 3 × 10⁸ m/s

Wavelength, λ = 1.55 μm = 1.55 × 16^-6 m

Energy gap, E_g = ?

2.    Calculate the wavelength of emitted radiation from GaAs which has a band gap of 1.44 eV.

 

(Set-3–May 2008)

Sol: Energy gap of semiconductor, E_g = hν

h = Planck’s constant = 6.63 × 10^-34 J-S