Optimisation of the dislocation filter layers in 1.3-μm InAs/GaAs quantum-dot lasers monolithically grown on Si substrates

The authors report 1.3-mu m InAs/GaAs quantum-dot (QD) lasers monolithically grown on a Si substrate by optimising the dislocation filter layers (DFLs). InAlAs/GaAs strained layer superlattices (SLSs) have been presented as DFLs in this study. A distinct improvement in the InAs/GaAs QDs was observed when using InAlAs/GaAs SLSs because of the effective filtering of threading dislocations. Consequently, a laser with a threshold current density of 194 A/cm(2) at room temperature and an operating temperature as high as 85 degrees C is successfully demonstrated. These results show the potential for integrating III-V QD materials on a Si platform via InAlAs/GaAs SLSs as DFL.