نتایج جستجو برای: qws

تعداد نتایج: 319  

2012
Dominik Heinz

We report on the large area realization of GaN photonic crystal slabs with semipolar InGaN quantum wells (QWs) using laser interference lithography and selective area metalorganic vapour phase epitaxy (MOVPE). Directional extraction of guided modes was observed in angle-resolved photoluminescence spectroscopy (ARPL), and the photonic crystal slab dispersion relation was measured. A comparison o...

Journal: :Microelectronics Journal 2009
A. Molina A. García-Cristóbal A. Cantarero

The electronic structure of wurtzite semiconductor superlattices (SLs) and quantum wells (QWs) is calculated by using the empirical tight-binding method. The basis used consists of four orbitals per atom (sp model), and the calculations include the spin-orbit coupling as well as the strain and electric polarization effects. We focus our study on GaN/AlN quantum wells grown both in polar (C) and...

Journal: :Nanotechnology 2014
A V Kuchuk V P Kladko T L Petrenko V P Bryksa A E Belyaev Yu I Mazur M E Ware E A DeCuir G J Salamo

We report on the mechanism of strain-influenced quantum well (QW) thickness reduction in GaN/AlN short-period superlattices grown by plasma-assisted molecular beam epitaxy. Density functional theory was used to support the idea of a thermally activated exchange mechanism between Al adatoms and Ga surface atoms that is influenced by the strain state of the GaN QWs. These ab initio calculations s...

2002
M. S. Torre C. Masoller

We study the transversemode selection of aweakly index-guided vertical-cavity surface-emitting laser (VCSEL), based on an extension of the model of Valle et al. [Opt. Commun. 115 (1995) 297]. In the model we incorporate carrier capture and escape processes between the separate confinement heterostructure (SCH) layer and the quantum well (QW) active region of a VCSEL. These effects are character...

Journal: :Physical review 2021

Two-dimensional hole gases (2DHGs) in semiconductor quantum wells are promising platforms for spintronics and computation, but suffer from the lack of $\mathbf{k}$-linear term Rashba spin-orbit coupling (SOC), which is essential spin manipulations without magnetism. The SOC 2DHGs commonly believed to be a $\mathbf{k}$-cubic as lowest order. Here, contrary conventional wisdom, we taking Ge/Si sy...

2013
Junjun Wang

Optically pumped green converter structures based on three-dimensional (3D) inverse pyramids were studied. The green emission intensity is determined by the conversion rate ηc and the absorption fraction ηa, indicating the InGaN/GaN quantum well (QW) crystal quality and its absorption capability, respectively. 15 was found to be the optimal QW number based the epitaxial condition for that serie...

2009
H. P. Zhao G. Y. Liu G. S. Huang J. D. Poplawsky S. Tafon Penn V. Dierolf N. Tansu

Staggered InGaN quantum wells (QWs) are investigated both numerically and experimentally as improved active region for light-emitting diodes (LEDs) emitting at 520–525 nm. Based on a self-consistent six-band k.p method, band structures of both two-layer staggered InxGa12xN/InyGa12yN QW and three-layer staggered InyGa12yN/InxGa12xN/InyGa12yN QW structures are investigated as active region to enh...

Journal: :Opto-electronic science 2023

Miniaturized light sources at telecommunication wavelengths are essential components for on-chip optical communication systems. Here, we report the growth and fabrication of highly uniform p-i-n core-shell InGaAs/InP single quantum well (QW) nanowire array emitting diodes (LEDs) with multi-wavelength high-speed operations. Two-dimensional cathodoluminescence mapping reveals that axial radial QW...

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