Hi,

We bought Si-doped GaAs substrates with a doping concentration of ~2x10^18 1/cm³.

In the photo luminescence (PL) of the bare wafers at 77 K we observe a broad peak at wavelengths above 900 nm and a huge and very broad peak around 1050 nm (beside the GaAs peak around 820 nm).

Does anybody know the origin of these (defect related) peaks?

The binding energy of Si in GaAs is usually ~6 meV.

Attached the PL of two wafers with comparable dopings and the PL of one undoped GaAs substrate.

Thanks a lot,

Arne