Electroluminescence and Photoluminescence of GaAs at 77°K

The electroluminescence from forward biased GaAs $p-n$ junctions is compared with the photoluminescence of bulk homogeneously doped samples of GaAs. It is found that in the region of the absorption edge at ≈ 1.48 eV, the electroluminescence is similar to the $p$-type photoluminescence, while at lower photon energy the electroluminescence is similar to the $n$-type photoluminescence. The results show that centers responsible for the low-energy electroluminescence are present in the substrate and not introduced during the diffusion.