Far field emission profile of pure wurtzite InP nanowires

Bulgarini, Gabriele; Dalacu, Dan; Poole, Philip J.; Lapointe, J.; Reimer, Michael E.; Zwiller, Val

doi:10.1063/1.4901437

Cited by 15 publications

(11 citation statements)

References 22 publications

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“…To quantify the absorption and emission between the components and to calculate the corresponding coupling weight matrix g ij , a full 3D model of the optical network with its node components was implemented in a Finite Difference Time Domain (FDTD) simulation using the solver from Lumerical . FDTD methods are widely used to model nanowire optical absorption, scattering, and emission, , demonstrating good agreement with experimental observations in nanostructures as used in the present study. In Figure a,b, the field distributions in the attractor ring due to one neural node LED (#3 in Figure a), as well as from an individual component, are seen.…”

Section: Resultssupporting

confidence: 72%

“…To simulate the absorption and emission between the components and calculate the corresponding coupling weight matrix 𝑔 𝑖𝑗 , we constructed a full 3D model of the optical network with its node components in the commercially available FDTD solver from Lumerical 36 . FDTD methods are widely used to model nanowire optical absorption 22 , scattering 37 , emission 18,38 , demonstrating good agreement with experimental observations. We determine the absorption of each device by calculating the optical transmission through a closed box around each absorption region in a component.…”

Section: Bottom Right)mentioning

confidence: 66%

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Implementing an Insect Brain Computational Circuit Using III–V Nanowire Components in a Single Shared Waveguide Optical Network

et al. 2020

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Recent developments in photonics include efficient nanoscale optoelectronic components and novel methods for subwavelength light manipulation. Here, we explore the potential offered by such devices as a substrate for neuromorphic computing. We propose an artificial neural network in which the weighted connectivity between nodes is achieved by emitting and receiving overlapping light signals inside a shared quasi 2D waveguide. This decreases the circuit footprint by at least an order of magnitude compared to existing optical solutions. The reception, evaluation, and emission of the optical signals are performed by neuron-like nodes constructed from known, highly efficient III–V nanowire optoelectronics. This minimizes power consumption of the network. To demonstrate the concept, we build a computational model based on an anatomically correct, functioning model of the central-complex navigation circuit of the insect brain. We simulate in detail the optical and electronic parts required to reproduce the connectivity of the central part of this network using previously experimentally derived parameters. The results are used as input in the full model, and we demonstrate that the functionality is preserved. Our approach points to a general method for drastically reducing the footprint and improving power efficiency of optoelectronic neural networks, leveraging the superior speed and energy efficiency of light as a carrier of information.

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Section: Resultssupporting

confidence: 72%

Section: Bottom Right)mentioning

confidence: 66%

Implementing an Insect Brain Computational Circuit Using III–V Nanowire Components in a Single Shared Waveguide Optical Network

et al. 2020

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“…26 To this day, most of the works done in literature concerning the far-field emission of single QD-NW or NW, is either in the visible or in the near-infrared 900-1000 nm range. 22,[26][27][28][29] However, no study has been reported yet on a single photon emission with a Gaussian far-field radiation in the telecom band from single QD-NWs monolithically grown on Si substrates.…”

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confidence: 99%

InAs quantum dot in a needlelike tapered InP nanowire: a telecom band single photon source monolithically grown on silicon

et al. 2019

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Realizing single photon sources emitting in the telecom band on silicon substrates is essential to reach complementary-metal-oxide-semiconductor (CMOS) compatible devices that secure communications over long distances. In this work, we propose the monolithic growth of needlelike tapered InAs/InP quantum dot-nanowires (QD-NWs) on silicon substrates with a small taper angle and a nanowire diameter tailored to support a single mode waveguide. Such a NW geometry is obtained by a controlled balance over axial and radial growths during the gold-catalyzed growth of the NWs by molecular beam epitaxy. This allows us to investigate the impact of the taper angle on the emission properties of a single InAs/InP QD-NW. At room temperature, a Gaussian farfield emission profile in the telecom O-band with a beam divergence angle θ = 30° is demonstrated from a single InAs QD embedded in a 2° tapered InP NW. Moreover, single photon emission is observed at cryogenic temperature for an off-resonant excitation and the best result, g 2 (0) = 0.05, is obtained for a 7° tapered NW. This all-encompassing study paves the way for the monolithic integration on silicon of an efficient single photon source in the telecom band based on InAs/InP QD-NWs.Epitaxy, Gaussian far-field emission profile, Telecom band, Silicon integration Non-classical light sources emitting at optical communication wavelength bands are of prime importance to quantum communication applications. One of these sources is the single photon source (SPS) which is the building block for realizing scalable on-chip devices for quantum 3 information processing. Once the single photons are generated, it is then required to manipulate the photons either to encode the information or to make the measurements. This means that the SPS must be integrated with compact photonic devices that can combine many optical components. Thanks to its large refractive index, silicon (Si) facilitates the fitting of a high number of optical components into a small device size making it a powerful platform for photonic integrated circuits. 1 Moreover, Si appears to be the most compatible material, due to the maturity of the complementary-metal-oxide-semiconductor (CMOS) fabrication methods, to combine electronics with photonics. 2 However, Si is an indirect band gap material which makes it a very poor light source. This issue can be solved by the monolithic integration, bonding or pick-andplace procedure of III-V materials on Si to fabricate CMOS compatible SPS. [3][4][5][6] In addition to the substrate choice, SPS emitting in the 1.3 µm and 1.5 µm telecom windows are required to reduce the losses for fiber-based long-haul communications. In particular, InAs quantum dots (QDs) have proven to be good candidates as efficient non classical light sources in these bands. 7,8 This requires embedding the QD in a nanophotonic structure such as nanowires (NWs), 9 micropillars, 10 optical horns, 11 photonic crystal cavities 12,13 and waveguides 14 in order to guide and efficiently extract the light in free space...

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“…As DFT calculations underestimate the band gap significantly, we perform a scissors shift of the conduction band states to the empirically known fundamental gaps of E g = 1.490 eV in wurtzite InP [57] and E g = 0.477 eV in wurtzite InAs [53], respectively. In fact, because the gap in InAs is small, the underestimation of the gap in calculations using the PBE functional leads to the closing of the gap.…”

Section: Band Structure Calculationsmentioning

confidence: 99%

Atomistic theory of electronic and optical properties of InAsP/InP nanowire quantum dots

2020

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We present here an atomistic theory of the electronic and optical properties of hexagonal InAsP quantum dots in InP nanowires in the wurtzite phase. These self-assembled quantum dots are unique in that their heights, shapes, and diameters are well known. Using a combined valenceforce-field, tight-binding, and configuration-interaction approach we perform atomistic calculations of single-particle states and excitonic, biexcitonic and trion complexes as well as emission spectra as a function of the quantum dot height, diameter and As versus P concentration. The atomistic tight-binding parameters for InAs and InP in the wurtzite crystal phase were obtained by ab initio methods corrected by empirical band gaps. The low energy electron and hole states form electronic shells similar to parabolic or cylindrical quantum confinement, only weakly affected by hexagonal symmetry and As fluctuations. The relative alignment of the emission lines from excitons, trions and biexcitons agrees with that for InAs/InP dots in the zincblende phase in that biexcitons and positive trions are only weakly bound. The random distribution of As atoms leads to dot-to-dot fluctuations of a few meV for the single-particle states and the spectral lines. Due to the high symmetry of hexagonal InAsP nanowire quantum dots the exciton fine structure splitting is found to be small, of the order a few µeV with significant random fluctuations in accordance with experiments.

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Far field emission profile of pure wurtzite InP nanowires

Cited by 15 publications

References 22 publications

Implementing an Insect Brain Computational Circuit Using III–V Nanowire Components in a Single Shared Waveguide Optical Network

Implementing an Insect Brain Computational Circuit Using III–V Nanowire Components in a Single Shared Waveguide Optical Network

InAs quantum dot in a needlelike tapered InP nanowire: a telecom band single photon source monolithically grown on silicon

Atomistic theory of electronic and optical properties of InAsP/InP nanowire quantum dots

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