Observation of optical anisotropy of GaAsSb-capped InAs quantum dots

摘要

Self-Assembled InAs Quantum Dots grown on GaAs substrates satisfy the qualitative requirement for photonic devices such as laser diode. And QDs formed by Strasky-Krastanov (SK) growth mode show a broad photoluminescence (PL) spectrum and in-plane asymmetries of dot shape and distribution of strain due to the nonuniformity of its size. In this study, we report the optical anisotropy of InAs QDs capped by GaAs_(1-x)Sb whose composition of Sb is different. GaAsSb cap layers allow the excitation wavelength of InAs QDs to be extended to the 1.55 μm region. We observed optical anisotropy of these samples at ground state by PL measurement.The samples are InAs QDs capped by GaAssb grown on a GaAs substrate by molecular beam epitaxy. The composition of Sb is 15% and 25%.We use the He-Ne laser as a light sauce whose excitation wavelength is 632.8 nm. The temperature of samples was set to 13 K. The degree of linear polarization (DLP) of the PL spectrum was measured by a set of a rotating half-wave plate and a fixed polarizer.