The effect of substrate temperature on the current threshold of GaAs-AlxGa1−xAs double-heterostructure lasers grown by molecular beam epitaxy

The current threshold densities (Jth) of broad-area double-heterostructure (DH) lasers, the photoluminescence (PL) intensities of the p-GaAs cap layers, P-AlxGa1−xAs (x∼0.3) confinement layers, and the GaAs active layers of the DH wafers are investigated as a function of the substrate temperature (450–650 °C) during MBE growth. The PL intensities of the P-AlxGa1−xAs (x∼0.3) confinement layers and the GaAs active layers increase and the Jth’s of the DH lasers decrease with increasing substrate temperature. The improvement of Jth with increasing substrate temperature is found to be well correlated to the improvement of the optical qualities of the AlxGa1−xAs layers with increasing substrate temperature. However, the PL intensities of the p-GaAs cap layers are relatively independent of substrate temperature.