Study of Two Different Deep Levels in Undoped LEC SI–GaAs by Photoluminescence Spectroscopy

Undoped LEC SI–GaAs crystals can be classified into two groups with respect to the deep PL emission band. One group dominantly exhibits emission peak energy at 0.8 eV, and the other at 0.65 eV. The profile along the growth direction and the wafer diameter for resistivity was similar to that for the 0.8 eV PL peak intensity in the 0.8 eV dominant crystals, while it was opposite to that for the 0.65 eV PL peak intensity in the 0.65 eV dominant crystals. The presence of these emission bands was found to depend on the growth conditions. Results suggest that two deep levels related to different origins are present in undoped LEC SI–GaAs.