A photodetector is made from a semiconductor In ${_{0.53}Ga}_{0.47}As$ with $E_g = 0.73 eV$. What is the maximum wavelength, which it can detect

1000 nm 1703 nm 500 nm 173 nm

1703 nm

Limiting value of $h_v$ is $E_g$, such that $hv=\frac{hc}{λ}=E_g$ or $λ=\frac{hc}{E_g}=\frac{6.63×10^{-34}J-s×3×10^8ms^{-1}}{0.73×1.6×10^{-19}J}=1703nm$