Band structures and optical properties of Ga1−xInxAs quantum wires grown by strain-induced lateral ordering

Abstract

Band structures and optical matrix elements of strained multiple quantum wires (QWRs) are investigated theoretically via the effective bond-orbital model, which takes into account the effects of valence band anisotropy and the band mixing. In particular, the Ga1−xInxAs QWRs grown by strain-induced lateral ordering (SILO) are considered. Recently, long wavelength Ga1−xInxAs QWR lasers have been fabricated via a single step molecular beam epitaxy technique which uses the SILO process [S. T. Chou, K. Y. Cheng, L. J. Chow, and K. C. Hsieh, Appl. Phys. Lett. 17, 2220 (1995); J. Appl. Phys. 78, 6270 (1995); J. Vac. Sci Technol. B 13, 650 (1995); K. Y. Cheng, K. C. Hsien, and J. N. Baillargeon, Appl. Phys. Lett. 60, 2892 (1992)]. Low threshold current and high optical anisotropy have been achieved. Multiaxial strains [combinations of biaxial strains in the (001) and (110) planes] for QWRs are considered. Our calculated anisotropy in optical matrix elements (for light polarized parallel versus perpendicular to the QWRs’ axis) is in good agreement with experiment. We also find that the strain tends to increase the quantum confinement and enhance the anisotropy of the optical transitions.