Temperature-insensitive semiconductor quantum dot laser

Different approaches to the design of a genuinely temperature-insensitive quantum dot (QD) laser are proposed. Suppression of the parasitic recombination outside the QDs, which is the dominant source of the temperature dependence of the threshold current in the conventional design of a QD laser, is accomplished either by tunneling injection of carriers into the QDs or by band-gap engineering. Elimination of this recombination channel alone enhances the characteristic temperatures T-0 above 1000 K. Remaining sources of temperature dependence (recombination from higher QD levels, inhomogeneous line broadening, and violation of charge neutrality in QDs) are studied. Tunnelinginjection structures are shown to offer an additional advantage of suppressed effects of inhomogeneous broadening and neutrality violation. (C) 2002 Elsevier Science Ltd. All rights reserved.