GaAs on (001) Si templates for near-infrared InP quantum dot lasers

Abstract

We investigated the effects of thermal cycle annealing (TCA) at high temperatures on the defect density and morphology of GaAs epilayers grown on (001) Si substrates. Several types of TCA combined with dislocation filter layers (DFLs) were introduced to reduce the defect densities in the GaAs grown on Si substrates. Plan-view transmission electron microscopy shows that the defect density of a 2.7  μm-thick GaAs/Si template with optimized TCA and DFLs is 1.4 × 107 cm−2, lower than a 1.1  μm-thick GaAs/Si template by a factor of 40. The surface roughness of the optimized GaAs/Si template is 1.3 nm after insertion of the DFLs. Additionally, optically pumped InP quantum dot micro-disk lasers (MDLs) were fabricated on these GaAs/Si templates to evaluate the template quality. Room-temperature continuous-wave lasing of 1.5  μm-diameter MDLs was observed, with ultralow lasing thresholds ranging from 0.5 to 2  μW.