Photoluminescence and photoluminescence excitation spectra of strained high-density InGaAs/Al_xGa_1-xas quantum wire structures on submicron grating

High-density In_0.2Ga_0.2As/Al_0.2Ga _0.8As quantum wire (QWR) gain-coupled distributed feedback (DFB) laser structures and an In_0.2Ga_0.8As/Al _0.38Ga_0.62As QWR structure were successfully grown on submicron gratings by a constant metalorganic chemical vapor deposition (MOCVD) growth technique in which submicron gratings were preserved even after an epitaxial growth of 1 μm thickness. Owing to the stronger quantum confinement effect of the AlGaAs barrier layer, strong photoluminescence from the QWR was observed even at room temperature. The Stokes shift of the QWR in the DFB laser structure was about 6 meV which indicates the high optical quality of the InGaAs/AlGaAs QWRs. The photoluminescence excitation spectra of the strained QWR did not show marked polarization anisotropy in contrast to those of the lattice-matched GaAs QWR due to the strain effects. It is expected that the high-density QWR structure fabricated using the constant MOCVD growth technique will be widely used in future photonic devices such as laser diodes and optical modulators.