What is the Band Gap for a GaAsP Semiconductor LED Emitting Red Light?

[diegoarmando]

Question: A light-emitting diode (LED) made of the semiconductor GaAsP gives off red light $$\lambda$$=650nm. what is the band gap for this semiconductor?




I know the E=hc/$$\lambda$$

so it means the band gap is 1240/650=1.9 ev ??

 

[mgb_phys]

Sounds right - you can adjust the bandgap of GaAsP to tune the wavelength but that's in the right range.