Conventional and Un-Conventional Lithography for Fabricating Thin Film Functional Devices

Thin film devices are conquering many aspects of today’s life, and continuous shrinking of building block dimensions of these structures enhances their performances and makes them economically attractive. This chapter is an overview of some conventional and unconventional lithography techniques used to fabricate thin film functional structures. Several aspects of pattern transfer were addressed with emphasis on the limits of these lithography techniques. We have thus highlighted the issue of pitch resolution for optical lithography and discussed some aspect of proximity effects for electron beam lithography. Pattern transfer from resist image to the wafer was also discussed. Considered as unconventional, we discussed several aspects linked to thin film fabrication using nanoimprint and nanosphere lithography techniques

Electroluminescence of Colloidal Quantum Dots in Electrical Contact with Metallic Nanoparticles

International audienceThe electroluminescence of a carpet of colloidal quantum dots in electrical contact with a metal nanoparticle array is investigated. The properties of the structures spectacularly differ from the well-known behavior of point sources placed at nonvanishing distances from subwavelength scatterers (robustness to quenching, coupling primarily defined by the electrical contact between the two species, etc.). This regime of short-range interactions can even be enabled with nonplasmonic inclusions made of platinum, providing an extreme case of enhanced and tailored light emission by quantum emitters in a highly absorptive environment. As a corollary, surface plasmons are not a necessary or sufficient ingredient but add functionalities that nonplasmonic structures do not possess. These findings indicate that the physics of localized light emitters in highly inhomogeneous environments is far from being fully understood and have important implications for the next generation of active metamaterials and advanced optoelectronic devices

Revisiting the Role of Metallic Antennas to Control Light Emission by Lead Salt Nanocrystal Assemblies

International audienceThin films of lead salt nanocrystals (NCs) offer attractive opportunities as active media for near-infrared optoelectronics but suffer from limiting trade-offs between optical and electrical properties. While NCs separated by nanometer-long ligands are good light emitters, NCs capped with shorter molecules provide a high carrier mobility but degrade the photo- and electroluminescence and broaden the narrow emission spectrum. Here we show that this severe quenching and spectral broadening can be averted with an unconventional use of metallic antennas. The resulting NC-antenna hybridization not only provides a strong boost in luminescence, but also makes it possible to remodel the emission spectrum in radical ways, even at wavelengths where the NC assembly does not emit light. These results cannot be explained with the standard theory of single-emitter luminescence assisted by optical antennas. We propose an alternative model based on a statistical description of light emission by an ensemble of emitters and discuss important consequences of our findings for nano-optics and solution-processed optoelectronics

Soft nanoimprint lithography on SiO2 sol-gel to elaborate sensitive substrates for SERS detection

This paper presents a new alternative fabrication of biochemical sensor based on surface enhanced Raman scattering (SERS) by soft nanoimprint lithography (S-NIL) on SiO2 sol-gel. Stabilization of the sol-gel film is obtained by annealing which simplifies the manufacturing of these biosensors and is compatible with mass production at low cost. This detector relies on a specific pattern of gold nanodisks on a thin gold film to obtain a better sensitivity of molecules’ detection. Characterizations of SERS devices were performed on a confocal Raman microspectrophotometer after a chemical functionalization. We report a lateral collapse effect on poly(diméthylsiloxane) (PDMS) stamp for specific nanostructure dimensions. This unintentional effect is used to evaluate S-NIL resolution in SiO2 sol-gel

Light propagation in metallic nanoparticle chains on SOI waveguide

International audienceIn this work, we demonstrate successful interfacing between metallic nanoparticle (MNP) chain supporting localized surface plasmons (LSP) and silicon-on-insulator (SOI) waveguides. We show that the optical energy carried by a TE SOI waveguide mode at telecom wavelengths can be efficiently transferred into MNP chains deposited on the waveguide top, whatever the number of metallic particles (from 5 to 50). Especially in short chains, most of the energy can be transferred into the fourth or fifth MNP of the chains. Predictions from theoretical models are fully corroborated by transmission and near-field measurements

Highly efficient interfacing of silicon-on-insulator and localized surface plasmon waveguides

International audiencePlasmonics implementation in optical circuits and interconnects requires interfacing with dielectric optical waveguides. We show here metallic nanoparticles chain mode excitation from SOI waveguide with a record distance lower than 600 nm at telecom wavelength

Giant Coupling Effect between Metal Nanoparticle Chain and Optical Waveguide

International audienceWe demonstrate that the optical energy carried by a TE dielectric waveguide mode can be totally transferred into a transverse plasmon mode of a coupled metal nanoparticle chain. Experiments are performed at 1.5 μm. Mode coupling occurs through the evanescent field of the dielectric waveguide mode. Giant coupling effects are evidenced from record coupling lengths as short as 560 nm. This result opens the way to nanometer scale devices based on localized plasmons in photonic integrated circuits

Highly efficient interfacing of silicon-on-insulator and localized surface plasmon waveguides

International audiencePlasmonics implementation in optical circuits and interconnects requires interfacing with dielectric optical waveguides. We show here metallic nanoparticles chain mode excitation from SOI waveguide with a record distance lower than 600 nm at telecom wavelength

Anodic Aluminum Oxide Replication for Soft UV-NIL Substrate Nanopatterning: Application in Biophysics

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Large area nanopatterning by combined Anodic Aluminum Oxide and soft UV-NIL technologies for applications in biology

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