Photonic graphene is a two-dimensional photonic crystal structure that is analogous to graphene. We use 5 mm diameter Al2O3 rods placed on a triangular lattice with a lattice constant a=8 mm to create an isolated conical singularity in the photonic band structure at a microwave frequency of 17.6 GHz. At this frequency, the measured transmission of microwaves through a perfectly ordered structure enters a pseudodiffusive regime where the transmission scales inversely with the thickness L of the crystal (L/a greater than or approximately 5). The transmission depends critically on the configuration of the edges: distinct oscillations with an amplitude comparable to the transmission are observed for structures terminated with zigzag edges, while these oscillations are absent for samples with a straight edge configuration.
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http://dx.doi.org/10.1103/PhysRevLett.104.043903 | DOI Listing |
Nat Nanotechnol
January 2025
Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
The miniaturization of light-emitting diodes (LEDs) is pivotal in ultrahigh-resolution displays. Metal-halide perovskites promise efficient light emission, long-range carrier transport and scalable manufacturing for bright microscale LED (micro-LED) displays. However, thin-film perovskites with inhomogeneous spatial distribution of light emission and unstable surface under lithography are incompatible with the micro-LED devices.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Applied Physics and Integrated Education Institute for Frontier Science and Technology (BK21 Four), Kyung Hee University, Yongin 17104, Korea.
One-dimensional (1D) vertical nitrides are highly attractive for light-emitting diode (LED) applications because they are useful for overcoming the drawbacks of conventional GaN planar structures. However, the internal quantum efficiency (IQE) of GaN multi-quantum-well (MQW) nanowire (NW) LEDs, typical 1D GaN structures, is still too low to replace standard planar LEDs. Here, we report a phenomenon of light amplification from core-shell InGaN/GaN NW LEDs by incorporating graphene quantum dots (GQDs).
View Article and Find Full Text PDFNano Lett
January 2025
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
Electro-optic (EO) modulation is a critical device action in photonics. Recently, the non-Drude dynamics induced by the Berry curvature dipole (BCD) in metals have attracted attention as a potential candidate for terahertz EO modulation. However, such BCD-induced EO effects can be challenging to realize, often requiring flat bands and complex materials such as a strained magic-angle twisted bilayer graphene on hexagonal boron nitride.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
Atomic defects in solids offer a versatile basis to study and realize quantum phenomena and information science in various integrated systems. All-electrical pumping of single defects to create quantum light emission has been realized in several platforms including color centers in diamond and silicon carbide, which could lead to the circuit network of electrically triggered single-photon sources. However, a wide conduction channel which reduces the carrier injection per defect site has been a major obstacle.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
College of Materials and Textile Engineering, Jiaxing University, Jiaxing 314001, China.
Programmable organization of uniform organic/inorganic functional building blocks into large-scale ordered superlattices has attracted considerable attention since the bottom-up self-organization strategy opens up a robust and universal route for designing novel and multifunctional materials with advanced applications in memory storage devices, catalysis, photonic crystals, and biotherapy. Despite making great efforts in the construction of superlattice materials, there still remains a challenge in the preparation of organic/inorganic hybrid superlattices with tunable dimensions and exotic configurations. Here, we report the spontaneous self-organization of polystyrene-tethered gold nanoparticles (AuNPs@PS) into freestanding organic/inorganic hybrid superlattices templated at the diethylene glycol-air interface.
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