Ultrahigh gain and non-radiative recombination channels in 1.5 µm range metamorphic InAs–InGaAs quantum dot lasers on GaAs substrates

Abstract

Metamorphic InAs–InGaAs quantum dot (QD) lasers grown on GaAs substrates by molecular beam epitaxy have been studied. The lasing wavelength of about 1.5 µm and the threshold current density of 1650 A cm−2 for a 2 mm cavity laser diode have been observed. The characteristic temperature of 66 K has been shown in the temperature range from 30 to 80 °C. The analysis of spontaneous emission efficiency corroborates the high contribution of non-radiative recombination in the total recombination current, even at high current densities. The possibility of achieving modal gain as high as 190 cm−1 has been demonstrated.