AlGaAs Bragg reflectors

Optical properties of Al_xGa_1-xAs Bragg reflectors, part 2

Simulation of reflectance spectra

The screen shot below shows a SCOUT (version 2) configuration for the investigation of a Bragg reflector based on 10 double layers of high and low aluminum content deposited on a GaAs substrate. Four parameters determine the reflectance: The two thickness values (d1 and d2) and the two composition parameters x1 and x2. The SCOUT view shows a sketch of the layer stack, the two relevant dielectric functions, the values of the four parameters and the corresponding reflectance spectrum in the range 1.0 ... 3.0 eV. Moving parameter sliders like the ones shown in the lower right corner one can easily inspect the influence of the individual parameters on the optical properties of the reflector.

Simulating various spectra and draging them to the Collect program one can generate useful 3D views that visualize the relations between parameters and spectra. Some examples are shown below.

Variation of the aluminum content x1 of layer 1 (d1=d2=80 nm, x2=0.8):

Thickness variation of layer 1 (x1=0.2, d2=80 nm, x2=0.8):

Variation of the number of double layers (x1=0.2, d1=d2=80 nm, x2=0.8):

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