Thermal Performance of GaInSb quantum well lasers for silicon photonics applications

A key component for the realisation of silicon-photonics are integrated lasers operating in the important communications band near 1.55 µm. One approach is through the use of GaSb-based alloys which may be grown directly on silicon. While GaSb-based lasers on silicon have been demonstrated, further development is needed to address high threshold current density and temperature sensitivity. In this study variable temperature and high hydrostatic pressure techniques were used to investigate the non-radiative loss mechanisms in the active region of strained Ga0.8In0.2Sb/Al0.35Ga0.65As0.03Sb0.97 composite quantum well (CQW) lasers grown on GaSb substrates emitting at 1.55 μm. While the temperature dependence of the threshold current characteristics at room temperature could be explained by both carrier leakage or Auger recombination, the differential quantum efficiency behaviour can only be explained by carrier leakage. The hydrostatic pressure investigation confirmed the presence of carrier leakage from the quantum well (QW) to the barrier X minima. While further improvement may be possible by increasing the width of the gain medium, carrier confinement could be improved by a small adjustment to the barrier Al and As alloy composition. The results of this investigation provide valuable design information for the ongoing monolithic integration of GaSb-based lasers on silicon.