Long-wavelength laser based on self-assembled InAs quantum dots in InAlGaAs on InP (001)

摘要

Seven stacks of self-assembled InAs quantum dots (QDs) separated by 28 nm thick InAlGaAs barriers were grown on InP (001) substrate by a solid-source molecular-beam epitaxy and were investigated by cross-sectional transmission electron microscopy and photoluminescence spectroscopy. Gain guided broad-area lasers with a stripe width of 75 μm were fabricated by using the seven-stacked InAs QD layers with the InAlGaAs-InAlAs material system on InP (001). The lasing operation from InAs QDs was observed up to 260 K and the characteristic temperature of the uncoated QD laser calculated from the temperature dependence of threshold current density was 377 K for temperatures up to 200 K, and 138 K above 200 K. The drastic decrease in the characteristic temperature above 200 K was mainly related to the thermal behavior of carriers in QDs, and possibly the thermal coupling of the QDs to the wetting layer and the waveguide region.