To date, quantum sources in the ultraviolet (UV) spectral region have been obtained only semiconductor dots. Color centers wide bandgap materials may represent a more effective alternative. However, quest for UV emitters bulk crystals faces difficulty of combining an efficient excitation/detection optical setup with capability addressing individual color potentially highly defective materials. In this work we overcome limit by employing original experimental coupling cathodoluminescence...

We have measured the second order correlation function [g^{(2)}(τ)] of cathodoluminescence intensity resulting from excitation by fast electrons defect centers in wide band-gap semiconductor nanocrystals diamond and hexagonal boron nitride. show that g^{(2)}(τ) multiple is dominated a large, nanosecond zero-delay bunching (g^{(2)}(0)>30), stark contrast to their flat photoluminescence function. developed model showing this can be attributed synchronized emission several excited same electron...

We demonstrate the strong influence of strain on morphology and In content InGaN insertions in GaN nanowires, agreement with theoretical predictions which establish that island nucleation nanowires may be energetically favorable, depending nanowire diameter. EDX analyses reveal inhomogeneities between successive dots but also along growth direction within each dot, is attributed to compositional pulling. Nanometer-resolved cathodoluminescence single allowed us probe luminescence dots,...

We investigated the optical properties of localized surface plasmons with different orders in individual silver nanotriangles sizes by electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) same scanning transmission microscope. EELS CL spectral imaging within give information about extinction scattering from nanostructures. As measured both techniques, first two order modes showed similar spatial distributions. However, appearances slightly resonant energies were confirmed...

The dependence of excited electron–hole state properties on the size their host semiconducting nanostructures is seed for a plethora applications such as light-emitting diodes (LEDs) and photovoltaic cells. However, inability state-of-the art, diffraction-limited optical techniques to probe lifetime variations at scale individual quantum emitters precludes full understanding nanostructures' properties. Here, we demonstrate measurement lifetimes few angströms thick separated by only...

Abstract Relativistic electron beams create optical radiation when interacting with tailored nanostructures. This phenomenon has been so far used to design grating-based and holographic electron-driven photon sources. It proposed recently that such sources can be for hybrid electron- light-based spectroscopy techniques. However, this demands the of a thin-film source suitable electron-microscopy applications. Here, we present mesoscopic structure composed an array nanoscale holes in gold...

Cathodoluminescence (CL) imaging spectroscopy provides two-dimensional optical excitation images of photonic nanostructures with a deep-subwavelength spatial resolution. So far, CL was unable to provide direct measurement the and emission probabilities in spatially resolved manner. Here, we demonstrate that by mapping cathodoluminescence autocorrelation function g(2) together spectral distribution rates can be disentangled at every position. We use InGaN/GaN quantum wells GaN nanowires...

Cathodoluminescence spectroscopy is a key analysis technique in nanophotonics research and technology, yet many aspects of its fundamental excitation mechanisms are not well understood on the single-electron single-photon level. Here, we determine cathodoluminescence emission statistics InGaN quantum wells embedded GaN under 6--30-keV electron find that light rate varies strongly from to electron. Strong photon bunching observed for at 2.77 eV due generation multiple excitations by single...

Abstract This conference proceeding reports on the usage and applications of a high numerical aperture mirror for cathodoluminescence other photon-based spectroscopies in scanning transmission electron microscope.

The structural and optical properties of axial GaN/InGaN/GaN nanowire heterostructures with high InN molar fractions grown by molecular beam epitaxy have been studied at the nanoscale a combination electron microscopy, extended x-ray absorption fine structure nano-cathodoluminescence techniques. up to 50% successfully incorporated without defects, as evidence potentialities for practical device realisation in such composition range. Taking advantage N-polarity self-nucleated GaN NWs on...

Thermal properties have an outsized impact on efficiency and sensitivity of devices with nanoscale structures, such as in integrated electronic circuits. A number thermal conductivity measurements for semiconductor nanostructures exist, but are hindered by the diffraction limit light, need transducer layers, slow scan rate probes, ultrathin sample requirements, or extensive fabrication. Here, we overcome these limitations extracting temperature maps from bandgap cathodoluminescence GaN...

In this paper, we show by optical and electron microscopy based investigations that vacancies in oxides may cluster form metallic nanoparticles induce coloration extinction of visible light. Optical case is caused generation localized surface plasmon resonances at particles embedded the dielectric matrix. Based on Mie's approach, are able to fit absorption due indium In2O3 our measurements. The experimentally found particle distribution excellent agreement with one obtained from fitting Mie...

We investigate the nanoscale excitation of Ag nanocubes with coherent cathodoluminescence imaging spectroscopy (CL) to resolve factors that determine spatial resolution CL as a deep-subwavelength technique. The 10–30 keV electron beam coherently excites localized plasmons in 70 nm cubes at 2.4 and 3.1 eV. radiation from these plasmon modes is collected far-field together secondary intensity. line scans across show exponentially decaying tails away cube reveal evanescent coupling field...

Photon bunching in incoherent cathodoluminescence (CL) spectroscopy originates from the fact that a single high-energy electron can generate multiple photons when interacting with material, thus, revealing key properties of electron–matter excitation. Contrary to previous works based on Monte Carlo modeling, here we present fully analytical model describing amplitude and shape second order autocorrelation function (g(2)(τ)) for continuous pulsed beams. Moreover, extend analysis photon...

The local density of optical states governs an emitters lifetime and quantum yield through the Purcell effect. It can be modified by a surface plasmon electromagnetic field, but such field has spatial extension limited to few hundreds nanometers, which complicates use methods spatially probe emitter-plasmon coupling. Here we show that combination electron-based imaging, spectroscopies photon-based correlation spectroscopy enables measurement effect with nanometer nanosecond spatio-temporal...

Nitrogen-vacancy (NV) centers in diamond are reliable single-photon emitters, with applications quantum technologies and metrology. Two charge states known for NV centers, NV0 NV-, the latter being mostly studied due to its long electron spin coherence time. Therefore, control over state of is essential. However, an understanding dynamics between different still remains challenging. Here, conversion from NV- electron-induced carrier generation shown. Ultrafast pump-probe cathodoluminescence...

Measurements of the photon second‐order correlation function, g (2) ( τ ), is a common tool for characterization single emitters, like nitrogen‐vacancy color centers in diamond. Such measurement requires background photoluminescence correction, which easy when this homogeneous on few wavelengths scale. However, if sample contains emitting separated by distance smaller than optical diffraction limit, and having different overlapping emission, these correction techniques cannot be applied. We...

Direct band gap III–V semiconductors, emitting efficiently in the amber–green region of visible spectrum, are still missing, causing loss efficiency light diodes operating this region, a phenomenon known as "green gap". Novel geometries and crystal symmetries however show strong promise overcoming limit. Here we develop novel material system, consisting wurtzite AlxIn1–xP nanowires, which is predicted to have direct green region. The nanowires grown with selective area metalorganic vapor...

Group III Nitrides nanowires are well suited materials for the design of light emitting devices. The internal electric field created by spontaneaous and piezoelectric polarizations in these poses some difficulties, but also possible solutions, towards this goal. Here, we report on high spatial asymmetry cathodoluminescence intensity across a GaN quantum embedded an AlN nanowire, when 60 keV, 1 nm wide electron beam is scanned over heterostructure. This remarkable between positions at...

We investigate, both experimentally and theoretically, the inelastic interaction between fast electrons electromagnetic field scattered by metallic apertures nanostructures on dielectric membranes using photon-induced near-field electron microscopy. The experiments, performed in a high-brightness ultrafast transmission microscope, gold silicon nitride reveal strong modulations of electron–light coupling strength. demonstrate that this effect results from combined action electric aperture...

We present the surface plasmon resonance modes in three-dimensional (3D) upright split ring resonators (SRR) as studied by correlative cathodoluminescence (CL) spectroscopy a scanning electron microscope (SEM) and energy loss (EELS) transmission microscope. discuss challenges inherent studying of 3D nanostructure how meeting these benefits from complementary use EELS SEM-CL. With EELS, we detect strong first order mode SRR; with comparison to simulations, are able identify this well-known...