Use of tilted-superlattices for quantum-well-wire lasers

Lasers with quantum-well-wire (QWW) active regions have been demonstrated using tilted-superlattice (TSL) structures with lateral dimensions in the low nanometer range. They are formed directly by molecular-beam epitaxy (MBE) without sophisticated lithography technologies. Separate-confinement-heterostructure lasers having TSL-QWWs as active regions were fabricated. The TSL-QWWs consist of a 5-nm GaAs layer and a 5-nm (AlGaAs(x=0.25)-GaAs) TSL layer which are sandwiched by AlGaAs(x=0.25) waveguide and AlGaAs (x=0.5) cladding layers. Threshold current densities as low as 460 A/cm/sup 2/ and differential quantum efficiencies of 29% per facet were obtained in a laser thus fabricated with a long cavity (1120 mu m) at room temperature. The lasing wavelength was 827 nm, which corresponds to the QWW state energy.