What composition x of AlxGa1-xAs would emit red light at 680 nm? What composition of GaAs1-xPx?

Question

What composition x of [latex]Al_xGa_{1-x} As[/latex] would emit red light at 680 nm? What composition of [latex]GaAs_{1-x}P_x[/latex]?

Accepted Answer

The band gap [latex]E_g(eV)=1.24/\lambda(\mu m)=1.24/0.68=1.82 \space eV[/latex].

From Fig. 3–6, we get [latex]Al_{0.32}Ga_{0.68}As[/latex].

From Fig. 8–10, we get [latex]GaAs_{0.68}P_{0.32}[/latex].

Question 8.3: What composition x of AlxGa1-xAs would emit red light at 680...