A molecular perspective on induced charges on a metallic surface

AbstractIntentional doping is the core of semiconductor technologies to tune electrical and optical properties of semiconductors for electronic devices, however, it has shown to be a grand challenge for halide perovskites. Here, we show that some metal ions, such as silver, strontium, cerium ions, which exist in the precursors of halide perovskites as impurities, can n-dope the surface of perovskites from being intrinsic to metallic. The low solubility of these ions in halide perovskite crystals excludes the metal impurities to perovskite surfaces, leaving the interior of perovskite crystals intrinsic. Computation shows these metal ions introduce many electronic states close to the conduction band minimum of perovskites and induce n-doping, which is in striking contrast to passivating ions such as potassium and rubidium ion. The discovery of metallic surface doping of perovskites enables new device and material designs that combine the intrinsic interior and heavily doped surface of perovskites.

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Directional Plasmonic Excitation by Helical Nanotips

Nanomaterials ◽

10.3390/nano11051333 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1333

Author(s):

Leeju Singh ◽

Nicolò Maccaferri ◽

Denis Garoli ◽

Yuri Gorodetski

Keyword(s):

Surface Plasmon ◽

Single Scattering ◽

Coupling Factor ◽

Metallic Surface ◽

Phase Matching ◽

Plasmon Excitation ◽

Surface Plasmon Excitation ◽

Specific Momentum ◽

Plasmon Polaritons ◽

Strong Spin

The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a nanoparticle or a nanohole, the coupling between a broadband effect, i.e., scattering, and a discrete one, such as surface plasmon excitation, leads to Fano-like resonance lineshapes. The necessary phase matching requirements can be used to engineer the light–plasmon coupling and to achieve a directional plasmonic excitation. Here, we investigate this effect by using a chiral nanotip to excite surface plasmons with a strong spin-dependent azimuthal variation. This effect can be described by a Fano-like interference with a complex coupling factor that can be modified thanks to a symmetry breaking of the nanostructure.

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High performing flexible optoelectronic devices using thin films of topological insulator

Scientific Reports ◽

10.1038/s41598-020-80738-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Animesh Pandey ◽

Reena Yadav ◽

Mandeep Kaur ◽

Preetam Singh ◽

Anurag Gupta ◽

...

Keyword(s):

Thin Films ◽

Optical Properties ◽

Nonlinear Optical ◽

Near Infrared ◽

Optoelectronic Devices ◽

Nonlinear Optical Properties ◽

Metallic Surface ◽

Strong Light ◽

High Performing ◽

Decay Times

AbstractTopological insulators (TIs) possess exciting nonlinear optical properties due to presence of metallic surface states with the Dirac fermions and are predicted as a promising material for broadspectral phodotection ranging from UV (ultraviolet) to deep IR (infrared) or terahertz range. The recent experimental reports demonstrating nonlinear optical properties are mostly carried out on non-flexible substrates and there is a huge demand for the fabrication of high performing flexible optoelectronic devices using new exotic materials due to their potential applications in wearable devices, communications, sensors, imaging etc. Here first time we integrate the thin films of TIs (Bi2Te3) with the flexible PET (polyethylene terephthalate) substrate and report the strong light absorption properties in these devices. Owing to small band gap material, evolving bulk and gapless surface state conduction, we observe high responsivity and detectivity at NIR (near infrared) wavelengths (39 A/W, 6.1 × 108 Jones for 1064 nm and 58 A/W, 6.1 × 108 Jones for 1550 nm). TIs based flexible devices show that photocurrent is linearly dependent on the incident laser power and applied bias voltage. Devices also show very fast response and decay times. Thus we believe that the superior optoelectronic properties reported here pave the way for making TIs based flexible optoelectronic devices.

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Theoretical studies of excitation dynamics in a peridinin-chlorophyll-protein coupled to a metallic nanoparticle

Open Physics ◽

10.2478/s11534-011-0003-x ◽

2011 ◽

Vol 9 (2) ◽

Cited By ~ 5

Author(s):

Mikolaj Schmidt ◽

Sebastian Mackowski

Keyword(s):

Energy Transfer ◽

Metallic Surface ◽

Energy Transfer Rate ◽

Metallic Nanoparticle ◽

Light Harvesting Complex ◽

Radiative Processes ◽

Förster Energy Transfer ◽

Chlorophyll Protein ◽

Induced Changes ◽

Excitation Dynamics

AbstractIn this work we study the influence of plasmon excitations on the excitation dynamics within a protein complex embedding two chlorophyll molecules coupled to a gold nanosphere. Small separation between the chlorophylls and metallic nanoparticle allows us to simplify the calculations of the Förster energy transfer rate and non-radiative processes by replacing a spherical nanoparticle with a metallic surface. Our results show modifications of all relevant processes and the energy transfer pathways within the system as well as the radiative processes. Plasmon induced changes result in strong qualitative effects of the fluorescence of the studied light-harvesting complex.

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Charge transfer from a metallic surface to an incoming ionic projectile

Journal of Physics Condensed Matter ◽

10.1088/0953-8984/5/33a/099 ◽

1993 ◽

Vol 5 (33A) ◽

pp. A287-A288 ◽

Cited By ~ 1

Author(s):

M Matos ◽

E F da Silveira ◽

F Perez

Keyword(s):

Charge Transfer ◽

Metallic Surface

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Novel die-sinking micro-electro discharge machining process using microelectromechanical systems technology

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes323ft ◽

2006 ◽

Vol 220 (9) ◽

pp. 1481-1487 ◽

Cited By ~ 1

Author(s):

J-B Li ◽

K Jiang ◽

G J Davies

Keyword(s):

Microelectromechanical Systems ◽

Machining Process ◽

Metallic Surface ◽

Manufacturing Cost ◽

Sem Images ◽

Deep Reactive Ion Etching ◽

Electro Discharge Machining ◽

Mems Technology ◽

Fabrication Condition ◽

Edm Process

A novel die-sinking micro-electro discharge machining (EDM) process is presented for volume fabrication of metallic microcomponents. In the process, a high-precision silicon electrode is fabricated using deep reactive ion etching (DRIE) process of microelectromechanical systems (MEMS) technology and then coated with a thin layer of copper to increase the conductivity. The metalized Si electrode is used in the EDM process to manufacture metallic microcomponents by imprinting the electrode onto a flat metallic surface. The two main advantages of this process are that it enables the fabrication of metallic microdevices and reduces manufacturing cost and time. The development of the new EDM process is described. A silicon component was produced using the Surface Technology Systems plasma etcher and the DRIE process. Such components can be manufactured with a precision in nanometres. The minimum feature of the component is 50 μm. In the experiments, the Si component was coated with copper and then used as the electrode on an EDM machine of 1 μm resolution. In the manufacturing process, 130 V and 0.2 A currents were used for a period of 5 min. The SEM images of the resulting device show clear etched areas, and the electric discharge wave chart indicates a good fabrication condition. The experimental results have been analysed and the new micro-EDM process is found to be able to fabricate 25 μm features.

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