Temperature-dependent Sellmeier equation for the refractive index of AlxGa1-xAs in the 1.46∼1.58 μm range

In this paper, we present a temperature-dependent Sellmeier equation for Al_xGa^1-xAs. This is a ternary alloy that is lattice matched to GaAs over the entire composition range and is the most commonly used alloy in semiconductor optoelectronic devices. Not only can aluminum mole fraction change the refractive index, but temperature can also play an important role. Thus, it would be of great interest to investigate the temperature-dependent variation of the refractive index of Al_xGa^1-xAs. This will be useful for in-situ monitoring when a sample is grown by molecular beam epitaxy (MBE) techniques. The experimental sample consisted of a GaAs DBR cavity with 18 pairs of GaAs/AlAs for top DBR stack and 22 pairs of GaAs/AlAs for bottom DBR stack. This structure is used to characterize and extract the parameters for the Sellmeier equation.