A GaInAsSb/AlGaAsSb multiple-quantum-well diode laser structure consisting of Al0.6Ga0.4As0.05Sb0.95cladding layers, Al0.3Ga0.7As0.02Sb0.98confining layers, and four 15-nm-thick Ga0.87In0.13As0.12Sb0.88quantum wells with 20-nm-thick Al0.3Ga0.7As0.02Sb0.98barrier layers was grown by organometallic vapor phase epitaxy. These lasers, emitting at 2.1&mgr;m, have exhibited pulsed threshold current densities as low as 1.2 kA/cm2. ©1997 American Institute of Physics.