Room temperature operation of AlInAs/AlGaAs quantum dot lasers

Separate confinement p-i-n heterostructures with highly strained InAlAs self-assembled quantum dots (QDs) in the active region have been grown by molecular beam epitaxy (MBE) on (001) GaAs. At low temperatures (4-50 K) stimulated emission occurs via excited states, followed by a transition from the excited states to the ground states from 50-140 K, with ground-state emission up to room temperatures. Structures with contact layers improving carrier confinement have a lowered current density threshold. For single QD layers, the dependence of threshold on dot density is found to be small. For increasing injection current, a broadening of the stimulated emission energy is also observed. (C) 1998 Elsevier Science B.V. All rights reserved.