Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTransverse magnetic routing of light emission in hybrid plasmonic-semiconductor nanostructures: Towards operation at room temperature
72
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We study experimentally and theoretically the temperature dependence of transverse magnetic routing of light emission from hybrid plasmonic-semiconductor quantum well structures where the exciton emission from the quantum well is routed into surface plasmon polaritons propagating along a nearby semiconductor-metal interface. In II-VI and III-V direct band semiconductors the magnitude of routing is governed by the circular polarization of exciton optical transitions, that is induced by a magnetic field. For structures comprising a (Cd,Mn)Te/(Cd,Mg)Te diluted magnetic semiconductor quantum well we observe a strong directionality of the emission up to 15% at low temperature of 20 K and magnetic field of 485 mT due to giant Zeeman splitting of holes mediated via the strong exchange interaction with Mn$^{2+}$ ions. For increasing temperatures towards room-temperature the magnetic susceptibility decreases and the directionality strongly decreases to 4% at T = 45 K. We also propose an alternative design based on a non-magnetic (In,Ga)As/(In,Al)As quantum well structure, suitable for higher temperatures. According to our calculations, such structure can demonstrate emission directionality up to 5% for temperatures below 200 K and moderate magnetic fields of 1 T.
rate research
Read More
Alternating layers of granular Iron (Fe) and Titanium dioxide (TiO$_{2-delta}$) were deposited on (100) Lanthanum aluminate (LaAlO$_3$) substrates in low oxygen chamber pressure using a controlled pulsed laser ablation deposition technique. The total thickness of the film was about 200 nm. The films show ferromagnetic behavior for temperatures ranging from 4 to $400 ^oK$. The layered film structure was characterized as p-type magnetic semiconductor at $300 ^oK$ with a carrier density of the order of $10^{20} /cm^3$. The undoped pure TiO$_{2-delta}$ film was characterized as an n-type magnetic semiconductor. The hole carriers were excited at the interface between the granular Fe and TiO$_{2-delta}$ layers similar to holes excited in the metal/n-type semiconductor interface commonly observed in Metal-Oxide-Semiconductor (MOS) devices. The holes at the interface were polarized in an applied magnetic field raising the possibility that these granular MOS structures can be utilized for practical spintronic device applications.
Magneto-optical phenomena such as the Faraday and Kerr effects play a decisive role for establishing control over polarization and intensity of optical fields propagating through a medium. Intensity effects where the direction of light emission depends on the orientation of the external magnetic field are of particular interest as they can be used for routing the light. We report on a new class of transverse emission phenomena for light sources located in the vicinity of a surface, where directionality is established perpendicularly to the externally applied magnetic field. We demonstrate the routing of emission for excitons in a diluted-magnetic-semiconductor quantum well. The directionality is significantly enhanced in hybrid plasmonic semiconductor structures due to the generation of plasmonic spin fluxes at the metal-semiconductor interface.
Hybrid nanophotonics based on metal-dielectric nanostructures unifies the advantages of plasmonics and all-dielectric nanophotonics providing strong localization of light, magnetic optical response and specifically designed scattering properties. Here we demonstrate a novel approach for fabrication of ordered hybrid nanostructures via femtosecond laser melting of asymmetrical metal-dielectric (Au-Si) nanoparticles created by lithographical methods. The approach allows selective reshaping of the metal components of the hybrid nanoparticles without affecting dielectric ones. We apply the developed approach for tuning of the hybrid nanostructures scattering properties in the visible range. The experimental results are supported by molecular dynamics simulation and numerical solving of Maxwell equations.
Room temperature strong coupling of WS_2 monolayer exciton transitions to metallic Fabry-Perot and plasmonic optical cavities is demonstrated. A Rabi splitting of 101 meV is observed for the Fabry-Perot cavity, more than double those reported to date in other 2D materials. The enhanced magnitude and visibility of WS_2 monolayer strong coupling is attributed to the larger absorption coefficient, the narrower linewidth of the A exciton transition, and greater spin-orbit coupling. For WS_2 coupled to plasmonic arrays, the Rabi splitting still reaches 60 meV despite the less favorable coupling conditions, and displays interesting photoluminescence features. The unambiguous signature of WS_2 monolayer strong coupling in easily fabricated metallic resonators at room temperature suggests many possibilities for combining light-matter hybridization with spin and valleytronics.
We report magnetism in carbon doped ZnO. Our first-principles calculations based on density functional theory predicted that carbon substitution for oxygen in ZnO results in a magnetic moment of 1.78 $mu_B$ per carbon. The theoretical prediction was confirmed experimentally. C-doped ZnO films deposited by pulsed laser deposition with various carbon concentrations showed ferromagnetism with Curie temperatures higher than 400 K, and the measured magnetic moment based on the content of carbide in the films ($1.5 - 3.0 mu_B$ per carbon) is in agreement with the theoretical prediction. The magnetism is due to bonding coupling between Zn ions and doped C atoms. Results of magneto-resistance and abnormal Hall effect show that the doped films are $n$-type semiconductors with intrinsic ferromagnetism. The carbon doped ZnO could be a promising room temperature dilute magnetic semiconductor (DMS) and our work demonstrates possiblity of produing DMS with non-metal doping.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
