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In this paper, we study both theoretically and experimentally the sensitivity of bimodal interferometric sensors where interference occurs between two plasmonic modes with different properties propagating in the same physical waveguide. In contrast to the well-known Mach–Zehnder interferometric (MZI) sensor, we show for the first time that the sensitivity of the bimodal sensor is independent of the sensing area length. This is validated by applying the theory to an integrated plasmo-photonic bimodal sensor that comprises an aluminum (Al) plasmonic stripe waveguide co-integrated between two accessible SU-8 photonic waveguides. A series of such bimodal sensors utilizing plasmonic stripes of different lengths were numerically simulated, demonstrating bulk refractive index (RI) sensitivities around 5700 nm/RIU for all sensor variants, confirming the theoretical results. The theoretical and numerical results were also validated experimentally through chip-level RI sensing experiments on three fabricated SU-8/Al bimodal sensors with plasmonic sensing lengths of 50, 75, and 100 μm. The obtained experimental RI sensitivities were found to be very close and equal to 4464, 4386, and 4362 nm/RIU, respectively, confirming that the sensing length has no effect on the bimodal sensor sensitivity. The above outcome alleviates the design and optical loss constraints, paving the way for more compact and powerful sensors that can achieve high sensitivity values at ultra-short sensing lengths. [ABSTRACT FROM AUTHOR]

2D materials display very promising intrinsic material properties, with multiple applications in electronics, photonics, and sensing. In particular layered platinum diselenide has shown high potential due to its layer‐dependent tunable bandgap, low‐temperature growth, and high environmental stability. Here, the conformal and area selective (AS) low‐temperature growth of layered PtSe2 is presented defining a new paradigm for 2D material integration. The thermally‐assisted conversion of platinum which is deposited by AS atomic layer deposition to PtSe2 is demonstrated on various substrates with a distinct 3D topography. Further the viability of the approach is presented by successful on‐chip integration of hybrid semiconductor devices, namely by the manufacture of a highly sensitive ammonia sensors channel with 3D topography and fully integrated infrared‐photodetectors on silicon photonics waveguides. The presented methodologies of conformal and AS growth therefore lay the foundation for new design routes for the synthesis of more complex hybrid structures with 2D materials. [ABSTRACT FROM AUTHOR]

The vertical charge transport through Si/SiOx multiple quantum wells (QWs) is investigated. Upon thermal annealing, segregation of excess Si from the SiOx layers leads to the formation of highly conductive pathways between Si grains from adjacent QWs separated by ultrathin silicon oxide barriers with barrier heights of 0.53–0.65 eV. Compared to stoichiometric Si/SiO2 layer stacks, conductivity is increased by up to ten orders of magnitude, which opens the way to an efficient charge carrier extraction in photovoltaic systems with distinct quantum confinement. [ABSTRACT FROM AUTHOR]

The vertical charge transport Si/Si[O.sub.x] multiple quantum wells (QWs) is examined. The studies have shown that when compared to stoichiometric Si/Si[O.sub.2] layer stacks, conductivity is increased by up to ten orders of magnitude, which has opened the way to an efficient charge carrier extraction in photovoltaic systems with distinct quantum confinement.

We present a technology platform supported by a new process design kit (PDK) that integrates two types of aluminum plasmonic waveguides with Si $_{3}$ N $_{4}$ photonics towards CMOS-compatible plasmo-photonic integrated circuits for sensing applications. More specifically, we demonstrate the fabrication of aluminum slot waveguide via e-beam lithography (EBL) on top of the Si $_{3}$ N $_{4}$ waveguide and an optimized fabrication process of aluminum plasmonic stripe waveguides within a CMOS foundry using EBL. Experimental measurements revealed a propagation length of 6.2 μm for the plasmonic slot waveguide in water at 1550 nm, reporting the first ever experimental demonstration of a plasmonic slot waveguide based on CMOS compatible metal materials in liquid environment. Propagation length in water for the aluminum stripe was measured equal to 66.8 μm which is, to the best of our knowledge, the highest value among all single-mode Al-based plasmonic waveguides presented so far at 1550 nm. Moreover, we evince with simulation data the sensing capabilities of the proposed structures when incorporated in a Si $_{3}$ N $_{4}$ -based interferometric configuration, yielding bulk sensitivity values up to 80 nm/RIU and 1300 nm/RIU, corresponding to an accumulated phase change per unit length of 0.77 π/RIU/μm and 1.26 π/RIU/μm for the aluminum slot and aluminum stripe waveguide, respectively. [ABSTRACT FROM AUTHOR]

Here in this work, we study the electro-refractive modulation of CVD grown single layer graphene placed on top of a silicon microring resonator biased using a polymer electrolyte gate. A voltage length product for a phase shift of π, VπL = 2.7 Vmm has been extracted, which is better compared to silicon depletion horizontal and interleaved pn junction type phase modulators and competitive with Silicon-Insulator-Silicon Capacitor modulators. [ABSTRACT FROM PUBLISHER]

ABSTRACT An algorithm to calculate the current in the two-diode equivalent circuit of a solar cell is described and characterized in detail. It enables fitting measured current-voltage characteristics with hundreds of voltage points and six fit parameters at practically instantaneous speeds and can handle thousands of voltage points within a few seconds, without simplifications of the two-diode model. This performance enables routine two-diode model parameter extraction at in-line speeds, which may help to enhance cell characterization for module integration. The source code is publicly available. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, we demonstrate single-sided screen-printed emitters in thin monocrystalline Czochralski silicon (Cz-Si) wafers with an improved gettering of iron compared with conventional double-sided POCl3 emitters. The phosphorus dopant pastes used have to be chosen carefully to provide a sufficiently low emitter sheet resistance and to avoid iron contamination. The iron concentration is determined in a non-destructive way from the minority carrier lifetime obtained by quasi-steady-state photoconductance measurements, down to levels not yet demonstrated for screen-printed emitters. In addition, the well-known metastable boron-oxygen complexes in Cz-Si have been transferred into a stable state by light-induced degradation prior to these measurements. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Interest in carbon dioxide (CO 2 ) sensors is growing rapidly due to the increasing awareness of the link between air quality and health. Indoor, high CO 2 levels signal poor ventilation, and outdoor the burning of fossil fuels and its associated pollution. CO 2 gas sensors based on integrated optical waveguides are a promising solution due to their excellent gas sensing selectivity, compact size, and potential for mass manufacturing large volumes at low cost. However, previous demonstrations have not shown adequate performance for atmospheric-level sensing on a scalable platform. Here, we report the clearly resolved detection of 500 ppm CO 2 gas at 1 s integration time and an extrapolated 1 σ detection limit of 73 ppm at 61 s integration time using an integrated suspended silicon waveguide at a wavelength of 4.2 µm. Our waveguide design enables suspended strip waveguides with bottom anchors while maintaining a constant waveguide core cross-sectional geometry. This unique design results in a low propagation loss of 2.20 dB/cm. The waveguides were implemented in a 150 mm silicon on insulator (SOI) platform using standard optical lithography, providing a clear path to low-cost mass manufacturing. The low CO 2 detection limit of our proposed waveguide, combined with its compatibility for high-volume production, creates substantial opportunities for waveguide sensing technology in CO 2 sensing applications such as fossil fuel combustion monitoring and indoor air quality monitoring for ventilation and air conditioning systems.

Metal-halide perovskites are a class of solution processed materials with remarkable optoelectronic properties such as high photoluminescence quantum yields and long carrier lifetimes, which makes them promising for a wide range of efficient photonic devices. In this work, we demonstrate the first successful integration of a perovskite laser onto a silicon nitride photonic chip. High throughput, low cost optical lithography is used, followed by indirect structuring of the perovskite waveguide. We embed methylammonium lead tri-iodide (MAPbI 3 ) in a pre-patterned race-track microresonator and couple the emitted light to an integrated photonic waveguide. We clearly observe the build-up of spectrally narrow lasing modes at room temperature upon a pump threshold fluence of 19.6 µJcm -2 . Our results evidence the possibility of on-chip lasers based on metal-halide perovskites with industry relevance on a commercially available dielectric photonic platform, which is a step forward towards low-cost integrated photonic devices.

Thermo-optical tuning of the refractive index is one of the pivotal operations performed in integrated silicon photonic circuits for thermal stabilization, compensation of fabrication tolerances, and implementation of photonic operations. Currently, heaters based on metal wires provide the temperature control in the silicon waveguide. The strong interaction of metal and light, however, necessitates a certain gap between the heater and the photonic structure to avoid significant transmission loss. Here we present a graphene heater that overcomes this constraint and enables an energy efficient tuning of the refractive index. We achieve a tuning power as low as 22 mW per free spectral range and fast response time of 3 µs, outperforming metal based waveguide heaters. Simulations support the experimental results and suggest that for graphene heaters the spacing to the silicon can be further reduced yielding the best possible energy efficiency and operation speed.