We report a synchrotron x-ray-diffraction study of the strain field in embedded In0.2Ga0.8As/GaAs ~001! quantum wires of widths 50–250 nm. Our results show a size-dependent orthorhombic lattice deformation in the wires and a linearly strained interfacial region near the wire sidewalls. The measured strain is responsible for an unusual band-gap energy increase that is several times larger than t...

In this work, we investigated the effects of quantum dot (QD) annealing (as-grown, 600°C-annealed, and 750°C-annealed) on the preliminary performances of 1.3-μm InAs-InGaAs-GaAs quantum dot electroabsorption modulators (QD-EAMs). Both extinction ratio and insertion loss were found to vary inversely with the annealing temperature. Most importantly, the 3-dB response of the 750°C-annealed lumped-...

We present a pseudopotential calculation of the single particle and excitonic spectrum of CdSe nanocrystals. We find that in the excitonic manifold derived from the ground state electron and the first 60 hole states there are two energy gaps much larger than the typical LO phonon energy in bulk CdSe. Such gaps can effectively slow down the hole relaxation process, as recently found experimental...

Edge-emitting mode-locked quantum-dot (QD) lasers are compact, highly efficient sources for the generation of picosecond and femtosecond pulses and/or broad frequency combs. They provide direct electrical control footprints down to few millimeters. Their gain bandwidths (up 50 nm ground state transitions as discussed below, with potential increase more than >200 by overlapping excited band tran...

In this work, we characterized the electronic structure of CdSe quantum dots embedded in a series x Na2O, (1–x) SiO2 glass matrices (x = 0, 0.25, 0.33, and 0.5). We analyzed impact matrix composition on both atomic dot (QD) QD/glass interface, as well luminescence mechanisms, using density functional theory calculations. The increase Na2O content was found to promote formation Cd–O Se–Na interf...

We study a five variable electron-hole model for a quantum dot (QD) laser subject to optical feedback. The model includes microscopically computed Coulomb scattering rates. We consider the case of a low linewidth enhancement factor and a short external cavity. We determine the bifurcation diagram of the first three external cavity modes and analyze their bifurcations. The first Hopf bifurcation...

The electronic conductance at zero temperature through a quantum wire with side-connected asymmetric quantum ring (as a scatter system) is theoretically studied using the non-interacting Hamiltonian Anderson tunneling method. In this paper we concentrate on the configuration of the quantum dot rings. We show that the asymmetric structure of QD-scatter system strongly influences the amplitude an...

We report for the first time a successful fabrication and operation of an InAs/GaAs quantum dot based intermediate band solar cell concentrator photovoltaic (QD-IBSC-CPV) module to the IEC62108 standard with recorded power conversion efficiency of 15.3%. Combining the measured experimental results at Underwriters Laboratory (UL®) licensed testing laboratory with theoretical simulations, we conf...

We report for the first time direct growth of quantum dot (QD) lasers with electrical pumping on 300 mm Si wafers both a planar template and in-pocket in-plane photonic integration. O-band five QD layers were grown molecular beam epitaxy (MBE) in reactor then fabricated into standard Fabry–Perot ridge waveguide cavities. Edge-emitting are demonstrated high yield reliable results ready commercia...