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oe1(光电查) - 科学论文

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?? 中文（中国） ▾

  • Long coherent dynamics of localized excitons in (In,Ga)N/GaN quantum wells

    摘要： We study the coherent dynamics of localized excitons in 100 periods of 2.5-nm-thick (In,Ga)N/GaN quantum wells with 7.5% indium concentration, measured with spectroscopic resolution through two-pulse and three-pulse photon echoes at the temperature of 1.5 K. A long-lived coherent exciton dynamics is observed in the (In,Ga)N quantum wells: When the laser photon energy is tuned across the 43-meV-wide inhomogeneously broadened resonance line, the coherence time T2 varies between 45 and 255 ps, increasing with stronger exciton localization. The corresponding narrow homogeneous linewidths ranging from 5.2 to 29 μeV as well as the relatively weak exciton-phonon interaction (0.7 μeV/K) confirm a strong, quantum-dot-like exciton localization in a static disordered potential inside the (In,Ga)N quantum well layers.

    关键词： localized excitons,photon echoes,exciton-phonon interaction,coherent dynamics,(In,Ga)N/GaN quantum wells

    更新于2025-09-23 15:21:01

  • Deep UV laser at 249 nm based on GaN quantum wells

    摘要： In this letter, we report on deep UV laser emitting at 249 nm based on thin GaN quantum wells (QWs) by optical pumping at room temperature. The laser threshold was 190 kW/cm2 that is comparable to state-of-the-art AlGaN QW lasers at similar wavelengths. The laser structure was pseudomorphically grown on a c-plane sapphire substrate by metalorganic chemical vapor deposition, comprising 40 pairs of 4 monolayer (ML) GaN QWs sandwiched by 6 ML AlN quantum barriers (QBs). The low threshold at the wavelength was attributed to large optical and quantum confinement, and high quality of the material, interface, and Fabry-P?rot facet. The emissions below and above the threshold were both dominated by transverse electric polarizations thanks to the valence band characteristics of GaN. This work unambiguously demonstrates the potentials of the binary AlN/GaN heterojunctions for high-performance UV emitters.

    关键词： GaN quantum wells,deep UV laser,UV emitters,AlN/GaN heterojunctions,optical pumping

    更新于2025-09-12 10:27:22

  • Hydrostatic and uniaxial effects in InGaN/GaN quantum wells

    摘要： We calculate strains, polarizations, and electric fields in InGaN/GaN quantum wells (lattice matched to GaN) under the influence of hydrostatic and uniaxial (along the c-axis) pressure. We calculate the confinement energies for electrons and holes, and we derive simple expressions for the transition energies and their pressure derivatives. We include the changes of the dielectric constant with pressure. The results seem compatible with the experimental data.

    关键词： confinement energies,transition energies,uniaxial pressure,electric fields,strain,InGaN/GaN quantum wells,polarization,hydrostatic pressure

    更新于2025-09-10 09:29:36