Articles you may be interested inGaAs-based room-temperature continuous-wave 1.59 μ m GaInNAsSb single-quantum-well laser diode grown by molecular-beam epitaxy Appl. Phys. Lett. 87, 231121 (2005) GaAsSb/ GaAs quantum well ͑QW͒ lasers grown by solid source molecular beam epitaxy are fabricated into ridge lasers and tested. These devices have a lasing wavelength around 1.2 m that is substantially blueshifted relative to the electroluminescence peak. The magnitude of the blueshift increases as the cavity length is shortened, indicating that the blueshift increases with injection level. This blueshift is attributed to material gain saturation and band filling effects. The internal quantum efficiency is ϳ75%, the transparency current density is ϳ120 A / cm 2 , and the threshold characteristic temperature is ϳ60 K, all typical for GaAsSb/ GaAs based edge emitting lasers. The extracted gain constant is ϳ800 cm −1 for single QW active regions and approximately half that amount for double QWs. This discrepancy is attributed to nonuniform carrier distribution in double QW structures.