InAs Quantum Dot Lasers with Extremely Low Threshold Current Density (7 A/cm2/Layer)

This paper describes the successful stacking of multilayered InAs quantum dots (QD) on a GaAs substrate up to 12 layers. The laser oscillated from the ground state under the condition of mirror loss at less than 7–8 cm-1. The extremely low threshold current density per QD-layer of 7 A/cm2/layer was obtained with a lasing wavelength of 1.21 µm at room temperature, which is the lowest value for any known semiconductor laser.