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Long wavelength light contains the infrared and terahertz (THz) spetral range of the spectrum. This wavelength range spans approximately from 1 µm to 1 mm. Several applications can be explored in this spectral range such as thermal imaging, temperature monitoring, night vision, etc. Moreover, molecular vibrations resonate at these energies that are the fingerprints for compounds identification via molecular spectroscopy. Also, THz light has an important role in security since at these frequencies is possible to achieve a higher resolution for imaging compared to millimeter waves that are typically used in airports. Despite all these potential applications, long wavelength light technology still remains non-fully exploited. One of the reasons is due to the lack of competing instrumentation such as sources, modulators, detectors, sensors, etc. In particular, regarding the detectors, the commercially available technology present some issues such as working at room temperature, speed, sensitivity, dynamic range, broadband frequency operation, CMOS compatibility, size and compactness, etc. The extensive research during the last years on graphene and other 2D materials has opened new possibilities of novel light matter interactions that can unveil the next generation photodectectors and sensors, ascribed to the advantages respect to conventional semiconductors. In this thesis, we focus on developing novel photodetection platforms in the mid, longwave infrared and THz range based on graphene pn-junctions with integrated metallic nanostructures and hyperbolic 2D material. We have successfully integrated an antenna with a graphene pn-junction for highly sensitive and fast THz detection in this regime. This novel terahertz detector exploits efficiently the photothermoelectric (PTE) effect, based on a design that employs a dual-gated, dipolar antenna with a nanogap. We have demonstrated that this novel detector leads to an excellent performance, which fulfills a combination of figure-of-merits that is currently missing in the state-of-the-art detectors. We also overcame the main challenge of infrared photodetectors, which is to funnel the light into a small nanoscale active area and efficiently convert it into an electrical signal. We achieve this by efficient coupling of a plasmonic antenna to hyperbolic phonon-polaritons in hBN to highly concentrate mid-infrared light into a graphene pn-junction. We use a metallic bowtie antenna and H-shape resonant gates that besides concentrating the light into its nanogap, their plasmonic resonances spectrally overlap within the upper reststrahlen band (RB) of hBN (6-7 µm), thus launching efficiently these HPPs and guiding them with constructive interferences towards the photodetector active area. Additionally, by having two different antennas orientation, it allows us to have sensitive detection in two incident polarizations. Furthermore, we have shown mid and long-wave infrared photocurrent spectroscopy via electrical detection of graphene plasmons, hyperbolic phonon-polaritons and their hybridized modes. We combined in one single platform the efficiently excited polaritonic material that also acts as a detector itself. We identified peaks in the photocurrent spectra that evolves and blue shift by increasing the gate voltage, which are related to the polaritonic resonances. Finally, we investigated the electrical detection of molecular vibrations coupled to hyperbolic phonon polaritons in hBN. We detected this strong light-matter interaction via a graphene pn-junction placed at the vicinity of the molecules-hBN stack. The edges of the gap of the local gates launch efficiently the hBN HPPs that interact with the CBP molecular resonances that are spectrally located at the upper RB. We explored this interaction as a function of the thickness of the molecular layers, near and far field contribution, etc. La luz de longitudes de onda largas consiste en el rango de infrarojo y terahercio (THz) del espectro. Este rango de longitud de ondas oscila entre los valores de 1 µm a 1 mm. En esta frecuencias, muchas aplicaciones pueden ser exploradas como por ejemplo las cámaras térmicas, monitorización de temperatura, visión nocturna, etc. Además, las vibraciones moleculares de muchos materiales oscilan en este rango de energías. Estas resonancias son utilizadas como huellas dactilares para la identificación de compuestos utilizando la espectroscopía molecular. También, la luz de terahercio juega un papel importante en el sector de seguridad. Esto se debe a que en estas frecuencias se puede conseguir una mayor resolución de imagen en comparación a las ondas milimétricas que son utilizadas mayoritariamente en los aeropuertos. A pesar de todo este potencial para diferentes sectores, la tecnología basada en luz de longitudes de onda largas sigue sin ser explotada del todo. Una de las razones es por la falta de equipos eficaces como por ejemplo las fuentes de luz, moduladores, detectores, sensores, etc. En particular, los detectores que se comercializan actualmente presentan limitaciones significativas como la temperatura de operación,velocidad, sensitividad, rango dinámico, ancho de banda de frecuencias, compatibilidad con CMOS, tamaño, etc. La investigación exhaustiva durante los últimos años en grafeno y otro materiales bidimensionales (2D) ha abierto nuevas posibilidades de nuevas interacciones entre materia y luz que podría contribuir para la nueva generación de fotodetectores y sensores debido a las ventajas de estos materiales respecto a los semiconductores convencionales. En esta tesis nos enfocaremos en el desarrollo de plataformas novedosos en fotodección en el infrarrojo medio, largo y en el rango de terahercio. Estas plataformas están basadas en junciones pn de grafeno integradas con nanoestructuras metálicas y materiales 2D hiperbólicos. Hemos integrado satisfactoriamente una antena con una junción pn de grafeno para una detección sensitividad alta y rápida de terahercio. Este fotodetector novedoso de terahercio utiliza eficientemente el efecto fototermoeléctrico, el cual esta basado en un diseño que emplea una antena con un nanogap que a su vez actúa como doble puerta. También hemos demostrado que este novedoso detector realiza un gran desempeño, consiguiendo una combinación de aspectos a destacar que actualmente no se encuentran en los detectores en literatura. Además. superamos el mayor desafío de los detectores de infrarrojo, el cual consiste en dirigir este tipo de luz en la nanoescala hacia el área activa del detector y convertirla en una señal eléctrica. Conseguimos esto mediante una acoplación eficiente de una antena plasmónica con los fonones polaritones hiperbólicos (HPPs) para concentrar altamente la luz infrarroja media a una junción pn de grafeno. Utilizamos una antenna "bowtie" metálica y unas puertas resonantes con forma de H que además de concentrar la luz en su nanogap, sus resonancias plasmónicas solapan espectralmente con la banda reststrahlen (RB) superior del hBN (6-7 µm). Esto induce a que se puedan excitar eficientemente los HPPs y se guian hacia la área activa del fotodetector mediante intereferencias constructivas. Más aún, hemos demostrado en la espectroscopía de fotocorriente en el infrarrojo medio y largo mediante la deteción eléctrica de polaritones 2D. Hemos combinado en una sola plataforma el material plasmónico que a su vez actúa como el fotodetector. Hemos identificado picos en el espectro de fotocorriente que evoluciona a medida que aumentamos el potencial de puerta, lo cual es una insignia de una resonancia polaritónica. Finalmente, investigamos la deteción eléctrica de vibraciones moleculares acopladas a HPPs en hBN. Hemos detectado esta fuerte interacción de luz y materia mediante una junción pn de grafeno que esta próxima a este Fotònica

International audience; The morphology, epitaxy, band-alignment and optical response of silver nanoparticles on ZnO(1010) has been analysed by microscopy, photoemission, electron diraction and dier-ential reectivity. At 700 K, clusters tend to nu-cleate and grow exclusively along [010]-oriented polar steps and corners, and not on at terraces or non-polar [001] steps. This preference leads to a specic epitaxy Ag(111)[110] ZnO[010](1010) with a large lattice mismatch along the dense row of the metal. The experiments have been rationalized through ab ini-tio simulations. A much lower adsorption energy is obtained for the O-terminated steps with a charge transfer from silver to oxygen, that corroborates the variation of ionization energy observed in photoemission and the presence of cationic silver. This anisotropy of growth reverberates in the plasmonic response of the metallic particles. The growth and epitaxy of metals on the polar (0001) and non-polar (1010) ori-entations of ZnO is discussed in terms of sur-face/step polarity compensation in the light of the present ndings.

Resumen del trabajo presentado a la 9th edition of the Graphene and 2D Materials International Conference and Exhibition, celebrada en Roma (Italia) del 25 al 28 de junio de 2019.

Resumen del trabajo presentado a la NanoSpain Conference, celebrada en Barcelona (España) del 28 al 31 de mayo de 2019.

Resumen del trabajo presentado a la 4th edition of the graphIn International Conference (Graphene Industry – Challenges and Opportunities), celebrada en Madrid (España) del 21 al 22 de febrero de 2019.

Photonic integrated circuits (PICs) for next-generation optical communication interconnects and all-optical signal processing require efficient (∼A/W) and fast (≥25 Gbs–1) light detection at low (–1) power consumption, in devices compatible with Si processing, so that the monolithic integration of electro-optical materials and electronics can be achieved consistently at the wafer scale. Graphene-based photodetectors can meet these criteria, thanks to their broadband absorption, ultra-high mobility, ultra-fast electron interactions, and strong photothermoelectric effect. High responsivities (∼ 1 A/W), however, have only been demonstrated in biased configurations, which introduce dark current, noise, and power consumption, while unbiased schemes, with low noise and zero consumption, have remained in the ∼ 0.1 A/W regime. Here, we consider the unbiased asymmetric configuration and show that optimized plasmonic enhanced devices can reach for both transverse-electric and transverse-magnetic modes (at λ = 1550 nm), ∼A/W responsivity, and ∼ 100 GHz operation speed at zero power consumption. We validate the model and material parameters by simulating experimental devices and derive analytical expressions for the responsivity. Our comprehensive modeling paves the way for efficient, fast, and versatile optical detection in PICs with zero power consumption.