Keywords: quantum dots, semiconductor lasers, nanomaterials, threshold current density, self assembly, spontaneous emission, carrier distribution, nanotechnology, temperature
Effect of temperature on threshold current density in InP/AlGaInP quantum dot laser structures
The authors have grown self-assembled InP quantum dot lasers on GaAs substrate by MOVPE with 750°C growth temperature. The operating temperature has a distinctive effect on the threshold current density. The authors have measured the threshold current density between 190-350K. At low temperatures, the threshold current increases with temperature, reaches a local maximum and then decreases for further increase in temperature before increasing again at temperatures above 280K. This behaviour is explained, using measurements of the spontaneous emission spectra at threshold, in terms of the carrier distribution in the quantum dot and quantum well states, without the need to invoke the temperature dependence of Auger recombination.