INGAAS GAAS QUANTUM-DOT LASERS WITH ULTRAHIGH CHARACTERISTIC TEMPERATURE (T-0=385K) GROWN BY METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION/

Low threshold current density (AlInGa)As/GaAs lasers based on InGaAs q uantum dots (QDs) are grown by metal organic chemical vapour depositio n (MOCVD). Quantum dots deposited at 490 degrees C and covered with Ga As are directly revealed in the active region. On a transmission elect ron microscopy (TEM) image of the laser structure no large clusters or dislocations are found over a macroscopic distance. We show that the properties of QD lasers can be strongly improved if the QDs are confin ed by Al0.3Ga0.7As barriers and the cladding layers are grown at high temperature. Optimisation of the laser structure geometry allows exten sion of the range of ultrahigh temperature stability (T-0 = 385 K) of the threshold current to 50 degrees C.