Room temperature lasing of GaAs quantum wire vertical-cavity surface-emitting lasers grown on (7Â 7Â 5)B GaAs substrates by molecular beam epitaxy

Self-organized GaAs/(GaAs)4(AlAs)2 quantum wires (QWRs) grown on (7 7 5)B-oriented GaAs substrates by molecular beam epitaxy have been applied to an active region of vertical-cavity surface-emitting lasers (VCSELs). The (7 7 5)B GaAs QWR-VCSEL with an aperture diameter of 3 μm lased at a wavelength of 765 nm with a threshold current of 0.38 mA at room temperature. This is the first demonstration of laser operation of the QWR-VCSEL by current injection. The light output was linearly polarized in the direction parallel to the QWRs due to the optical anisotropy of the self-organized (7 7 5)B GaAs QWRs.