TY - JOUR

T1 - Simulating Electron Energy-Loss Spectroscopy and Cathodoluminescence for Particles in Arbitrary Host Medium Using the Discrete Dipole Approximation

AU - Kichigin, Alexander A.

AU - Yurkin, Maxim A.

N1 - ACKNOWLEDGMENTS: The authors thank Søren Raza for providing experimental data shown in Figure 10 and Mathias Kobylko for providing experimental images shown in Figure 11. They also thank Tomas Ostasevic ̌ ius ̌ for making the first prototype of EELS simulations in the ADDA code and Alexander Moskalensky for implementing the support of host medium in this code (for light scattering simulations). The theoretical developments and implementation of EELS simulations in ADDA were supported by Russian Foundation for Basic Research (Grant No. 18-01-00502). The comparisons with the BEM and experiments, the study of simulation accuracy, and adding the support of absorbing host medium to ADDA were supported by the Russian Science Foundation (Grant No. 18-12-00052).

PY - 2023/3/2

Y1 - 2023/3/2

N2 - Electron energy-loss spectroscopy (EELS) and cathodoluminescence (CL) are widely used experimental techniques for characterization of nanoparticles. The discrete dipole approximation (DDA) is a numerically exact method for simulating the interaction of electromagnetic waves with particles of arbitrary shape and internal structure. In this work, we extend the DDA to simulate EELS and CL for particles embedded into arbitrary (even absorbing) unbounded host medium. The latter includes the case of the dense medium, supporting the Cherenkov radiation of the electron, which has never been considered in EELS simulations before. We build a rigorous theoretical framework based on the volume integral equation, final expressions from which are implemented in the open-source software package ADDA. This implementation agrees with both the Lorenz-Mie theory and the boundary-element method for spheres in vacuum and moderately dense host medium. And it successfully reproduces the published experiments for particles encapsulated in finite substrates. The latter is shown for both moderately dense and Cherenkov cases─a gold nanorod in SiO2 and a silver sphere in SiNx, respectively. For the nanorod, we successfully reproduced the EELS plasmon maps (scans across the particle cross section), although the developed theory is not fully rigorous for electron trajectories intersecting a particle.

AB - Electron energy-loss spectroscopy (EELS) and cathodoluminescence (CL) are widely used experimental techniques for characterization of nanoparticles. The discrete dipole approximation (DDA) is a numerically exact method for simulating the interaction of electromagnetic waves with particles of arbitrary shape and internal structure. In this work, we extend the DDA to simulate EELS and CL for particles embedded into arbitrary (even absorbing) unbounded host medium. The latter includes the case of the dense medium, supporting the Cherenkov radiation of the electron, which has never been considered in EELS simulations before. We build a rigorous theoretical framework based on the volume integral equation, final expressions from which are implemented in the open-source software package ADDA. This implementation agrees with both the Lorenz-Mie theory and the boundary-element method for spheres in vacuum and moderately dense host medium. And it successfully reproduces the published experiments for particles encapsulated in finite substrates. The latter is shown for both moderately dense and Cherenkov cases─a gold nanorod in SiO2 and a silver sphere in SiNx, respectively. For the nanorod, we successfully reproduced the EELS plasmon maps (scans across the particle cross section), although the developed theory is not fully rigorous for electron trajectories intersecting a particle.

UR - https://www.scopus.com/inward/record.url?eid=2-s2.0-85148305048&partnerID=40&md5=11bd0fe6b3c122ecdfbdc18f352a916d

UR - https://www.mendeley.com/catalogue/d2010405-02a5-3de6-ae03-1e8fc9834c63/

U2 - 10.1021/acs.jpcc.2c06813

DO - 10.1021/acs.jpcc.2c06813

M3 - Article

VL - 127

SP - 4154

EP - 4167

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 8

ER -