InAs quantum dot lasers with extremely low threshold current density (7A/cm(2)/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 7A/cm(2)/layer was obtained with a lasing wavelength of 1.21 mu m at room temperature, which is the lowest value for any known semiconductor laser.