InGaAs/GaAs Quantum Dot Lasers with Ultrahigh Characteristic Temperature (T₀= 385 K) Grown by Metal Organic Chemical Vapour Deposition

Abstract

Low threshold current density (AlInGa)As/GaAs lasers based on InGaAs quantum dots (QDs) are grown by metal organic chemical vapour deposition (MOCVD). Quantum dots deposited at 490° C and covered with GaAs are directly revealed in the active region. On a transmission electron 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 confined by Al 0.3 Ga 0.7 As barriers and the cladding layers are grown at high temperature. Optimisation of the laser structure geometry allows extension of the range of ultrahigh temperature stability ( T 0 =385 K) of the threshold current to 50° C.