Toward quantum dot laser diodes emitting at 1.5 μm

Abstract

Quantum Dot laser diodes have been made using InAs self- assembled quantum dots (QDs) in the active region of separate confinement heterostructures. The lasers grown by Molecular Beam Epitaxy (MBE) with stacked InAs QDs grown on GaAs gave record low thresholds of 13 A/cm<SUP>2</SUP> at 77 K and 82 A/cm<SUP>2</SUP> at 15 degree(s)C. On InP substrates, InAs QDs have been grown by Metal-Organic Chemical Vapor Deposition (MOCVD) with InP claddings, and by MBE in InGaAlAs separate confinement heterostructures. For the InAs/InP by MOCVD, the QD photoluminescence (PL) peaks between 1.51 micrometers and 1.57 micrometers at 77 K and close to 1.6 micrometers at 300 K. Transmission Electron Microscope analysis correlated with the PL results reveal that the QD density depends on the growth interrupt time which follows the InAs deposition. For the InAs/InGaAlAs by MBE, the QD electroluminescence peaks at approximately 1.42 micrometers at 300 K.