AI Article Synopsis
- Understanding light absorption in individual nanostructures is vital for improving light-matter interactions at the nanoscale, and a new technique called time-reversed Fourier microscopy is introduced to measure this in semiconductor nanowires.
- The study reveals how individual nanowires, treated as nanoantennas, exhibit different absorption behaviors depending on the angle of incoming light, showcasing a shift from guided-mode to Mie-resonance absorption.
- Key findings indicate that Mie theory does not adequately explain absorption in vertical nanowires at small light angles, emphasizing the importance of guided modes for achieving better absorption, which can enhance the efficiency of nanowire-based devices like photodetectors and solar cells.
Article Abstract
Understanding light absorption in individual nanostructures is crucial for optimizing the light-matter interaction at the nanoscale. Here, we introduce a technique named time-reversed Fourier microscopy that enables the measurement of the angle-dependent light absorption in dilute arrays of uncoupled semiconductor nanowires. Because of their large separation, the nanowires have a response that can be described in terms of individual nanostructures. The geometry of individual nanowires makes them behave as nanoantennas that show a strong interaction with the incident light. The angle-dependent absorption measurements, which are compared to numerical simulations and Mie scattering calculations, show the transition from guided-mode to Mie-resonance absorption in individual nanowires and the relative efficiency of these two absorption mechanisms in the same nanostructures. Mie theory fails to describe the absorption in finite-length vertical nanowires illuminated at small angles with respect to their axis. At these angles, the incident light is efficiently absorbed after being coupled to guided modes. Our findings are relevant for the design of nanowire-based photodetectors and solar cells with an optimum efficiency.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/nl5005948 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
High-Efficiency Nanowire Solar Cells with Omnidirectionally Enhanced Absorption Due to Self-Aligned Indium-Tin-Oxide Mie Scatterers.
ACS Nano
December 2016
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Photovoltaic cells based on arrays of semiconductor nanowires promise efficiencies comparable or even better than their planar counterparts with much less material. One reason for the high efficiencies is their large absorption cross section, but until recently the photocurrent has been limited to less than 70% of the theoretical maximum. Here we enhance the absorption in indium phosphide (InP) nanowire solar cells by employing broadband forward scattering of self-aligned nanoparticles on top of the transparent top contact layer.
View Article and Find Full Text PDFDetermination of time-reversal symmetry breaking lengths in an InGaAs interferometer array.
J Phys Condens Matter
May 2015
Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA.
Quantum interference oscillations due to the Aharonov-Bohm phase were measured in a ring interferometer array fabricated on a two-dimensional electron system in an InGaAs/InAlAs heterostructure. Coexisting oscillations with magnetic flux periodicity h/e and h/2e were observed and their amplitudes compared as function of applied magnetic field. The h/2e oscillations originate in time-reversed trajectories with the ring interferometers operating in Sagnac-type mode, while the h/e oscillations result from Mach-Zehnder operation.
View Article and Find Full Text PDFTime-reversal (TR) phase prints are first used in far-field (FF) detection of sub-wavelength (SW) deformable scatterers without any extra metal structure positioned in the vicinity of the target. The 2D prints derive from discrete short-time Fourier transform of 1D TR electromagnetic (EM) signals. Because the time-invariant intensive background interference is effectively centralized by TR technique, the time-variant weak indication from FF SW scatterers can be highlighted.
View Article and Find Full Text PDFNanowire antenna absorption probed with time-reversed fourier microscopy.
Nano Lett
June 2014
FOM Institute for Atomic and Molecular Physics (AMOLF), c/o Philips Research, High-Tech Campus 4, 5656 AE Eindhoven, The Netherlands.
Article Synopsis
- Understanding light absorption in individual nanostructures is vital for improving light-matter interactions at the nanoscale, and a new technique called time-reversed Fourier microscopy is introduced to measure this in semiconductor nanowires.
- The study reveals how individual nanowires, treated as nanoantennas, exhibit different absorption behaviors depending on the angle of incoming light, showcasing a shift from guided-mode to Mie-resonance absorption.
- Key findings indicate that Mie theory does not adequately explain absorption in vertical nanowires at small light angles, emphasizing the importance of guided modes for achieving better absorption, which can enhance the efficiency of nanowire-based devices like photodetectors and solar cells.
Guided wave topological imaging of isotropic plates.
Ultrasonics
September 2014
Univ. Bordeaux, I2M - UMR 5295, F-33400 Talence, France; CNRS, I2M - UMR 5295, F-33400 Talence, France; Arts et Métiers ParisTech, I2M - UMR 5295, F-33400 Talence, France.
Topological imaging is a recent method. So far, it has been applied to bulk waves, and high resolution has been demonstrated for imaging scatterers even with a single ultrasonic insonification of the inspected medium. This method consists of (i) emitting waves and measuring the response of the medium; (ii) solving two propagation problems: the direct problem, where the experimental source is simulated, and the adjoint problem, where the source is the time-reversed difference between the measured wave field and that obtained from the direct problem; (iii) computing the image by simply multiplying both wave fields together in the frequency domain, and integrating over the frequency.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!