6190-Å emission at 77 K of Ga1−xAlxAs double heterostructure lasers

The Ga1−xAlxAs laser diodes which emit a wavelength of 6190 Å at 77 K with threshold current densities as low as 300 A/cm2 were fabricated using a double heterostructure with lightly doped active regions. This lasing wavelength is the shortest ever attained in Ga1−xAlxAs lasers for such a low threshold current density. The maximum external quantum efficiency of these diodes was found to be about 35% at 77 K. The extensive studies made of the properties of these visible-light-emitting lasers, especially of the spectral distributions, are described in full detail.