III-V compound semiconductor nanowires (NWs), with their direct bandgaps and high mobilities, have been shown to be promising materials for many applications including solar cells, light emitting diodes, transistors, and lasers. Self-aligned, twin-plane-defect free, planar GaAs NWs can be grown by metalorganic chemical vapor deposition (MOCVD) through the… (More)
In this work we describe the carrier depletion MZI modulators, slow wave structures for modulation enhancement and the QCSE modulator which are under development in the European HELIOS project and the UK Silicon Photonics project.
We report the direct determination of nonradiative lifetimes in Si/ SiGe asymmetric quantum well structures designed to access spatially indirect ͑diagonal͒ interwell transitions between heavy-hole ground states, at photon energies below the optical phonon energy. We show both experimentally and theoretically, using a six-band k · p model and a time-domain… (More)
—Producing an electrically pumped silicon-based laser at terahertz frequencies is gaining increased attention these days. This paper reviews the recent advances in the search for a silicon-based terahertz laser. Topics covered include resonant tunneling in p-type Si/SiGe, terahertz intersubband electroluminescence from quantum cascade structures,… (More)
Ge on Si micro-disk, ring and racetrack cavities are fabricated and strained using silicon nitride stressor layers. Photoluminescence measurements demonstrate emission at wavelengths ≥ 2.3 μm, and the highest strained samples demonstrate in-plane, tensile strains of > 2 %, as measured by Raman spectroscopy. Strain analysis of the micro-disk structures… (More)
Copyright and reuse: The Warwick Research Archive Portal (WRAP) makes this work of researchers of the University of Warwick available open access under the following conditions. This article is made available under the Creative Commons Attribution-3.0 Unported (CC BY 3.0) license and may be reused according to the conditions of the license. For more details… (More)
Stable perfectly-matched-layer boundary conditions for finite-difference time-domain simulation of acoustic waves in piezoelectric crystals. Abstract Perfectly matched layer (PML) boundary conditions are derived for finite-difference time-domain analysis of acoustic waves within piezoelectric crystals. The robustness and effectiveness of the derived… (More)