Optimizations of Defect Filter Layers for 1.3-μm InAs/GaAs Quantum-Dot Lasers Monolithically Grown on Si Substrates

III-V semiconductors monolithically grown on Si substrates are expected to be an ideal solution to integrate highly efficient light-emitting devices on a Si platform. However, the lattice mismatch between III-V and Si generates a high density of threading dislocations (TDs) at the interface between III-V and Si. Some of these TD will propagate into the III-V active region and lead to device degradation. By introducing defect filter layers (DFLs), the density of TDs propagating into the III-V layers can be significantly reduced. In this paper, we present an investigation on the development of InGaAs/GaAs strained-layer superlattices as DFLs for 1.3-μm InAs/GaAs quantum-dot lasers monolithically grown on a Si substrate. We compare two broad-area InAs/GaAs quantum-dot lasers with non-optimized and optimized InGaAs/GaAs DFLs. The laser device with optimal DFLs has a lower room-temperature threshold current density of 99 A/cm2 and higher maximum operation temperature of 88 °C, compared with 174 A/cm2 and 68 °C for the reference laser.