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This work intends to investigate the impact of silicon layer thickness and substrate biasing on the UV photodetection efficiency of PIN diodes fabricated with ultra‐thin body and buried oxide (UTBB silicon‐on‐insulator [SOI]) technology, aiming to verify their behaviour on an ultimate commercial technology. UV photodetectors are applied in different fields, such as environmental and biomedical ones, and their implementation in UTBB SOI could enable the design of mixed circuits where data acquisition and processing could be made in the same chip, enhancing systems’ performance. It is shown that a 20‐nm‐thick silicon layer can be applied for UV photodetection and enhanced generated current is obtained when substrate bias is set to guarantee a depletion regime in the entire active layer. PIN diode devices implemented in the ultra‐thin body and buried oxide (UTBB silicon‐on‐insulator [SOI]) technology for photodetection applications. Very thin silicon layers can be applied for UV photodetection (wavelengths of around 350 nm) with the aid of active substrate biasing (Vsub). Maximum photogenerated current is reached for different Vsub ranges when P‐ and N‐type ground planes are implemented in a device with a silicon thickness of 20 nm.

An on‐chip dual‐mode all‐optical multifunctional logic operation unit including four AND and two OR logic gates is proposed and experimentally demonstrated. It is realized using multiple intra‐mode four‐wave mixing (FWM) processes in a multimode silicon waveguide for 2 × 10 Gbit/s non‐return‐to‐zero on–off‐keying (NRZ‐OOK) mode‐division multiplexing signals. The AND logic operation is realized via the non‐degenerate FWM processes, and the OR logic operation is realized by overlapping the two degenerate FWM idlers in frequency domain via appropriately selecting the dual‐mode pump wavelength. The two OR and four AND logic sequences are verified with NRZ‐OOK sequences for both TE0 and TE1 modes. We propose and experimentally demonstrate an on‐chip dual‐mode all‐optical multifunctional logic operation unit including four AND and two OR logic gates. It is realized using multiple intra‐mode four‐wave mixing (FWM) processes in a multimode silicon waveguide for 2 × 10 Gbit/s non‐return‐to‐zero on–off‐keying (NRZ‐OOK) mode‐division multiplexing signals. The two OR and four AND logic sequences are verified with NRZ‐OOK sequences for both TE0 and TE1 modes.

A novel junctionless gate‐all‐around (GAA) transistor with ultrathin nanosheet GAA channel and self‐aligned raised source/drain (RSD) is successfully designed and fabricated on void embedded silicon on insulator (VESOI) substrate through a much simpler fabrication process. Devices with as thin as 13‐nm nanosheet GAA channel thickness exhibit excellent electrical characteristics: on/off current ratio of 106 and on‐state drive current of 58 µA/µm. Although the parasitic planar channel component still exists, the device performance is decisively dominated by the GAA channel, and further boosted by the junction‐free bulk conduction mechanism and the self‐aligned RSD structure. A novel junctionless gate‐all‐around (GAA) transistor with ultrathin nanosheet GAA channel and self‐aligned raised source/drain (RSD) is successfully designed and fabricated on void embedded silicon on insulator (VESOI) substrate through a much simpler fabrication process. Devices with as thin as 13 nm nanosheet GAA channel thickness exhibit excellent electrical characteristics: on/off current ratio of 106 and on‐state drive current of 58 µA/µm.

Supplementary cementitious materials interact chemically and physically with cement, influencing the formation of hydrate compounds. Many authors have analyzed the filler and pozzolanic effect. However, few studies have explored the influence of these effects on hydration, properties in the fresh and hardened states, and durability parameters of cementitious composites separately. This study investigates the influence of the replacement of 20% of Portland cement for silica fume (SF) or a 20-µm medium diameter quartz powder (QP) on the properties of cementitious composites from the first hours of hydration to a few months of curing. The results indicate that SF is pozzolanic and that QP has no pozzolanic activity. The use of SF and QP reduces the released energy at early times to the control paste, indicating that these materials reduce the heat of hydration. The microstructure with fewer pores of SF compounds indicates that the pozzolanic reaction reduced pore size and binding capability, resulting in equivalent mechanical properties, reduced permeability and increased electrical resistance of the composites. SF and QP increase the carbonation depth of the composites. SF and QP composites are efficient in the inhibition of the alkali-aggregate reaction. The results indicate that, unlike the filler effect, the occurrence of pozzolanic reaction strongly influences electrical resistance, reducing the risk of corrosion of the reinforcement inserted in the concrete.

Electro-optic modulators have been identified as the key drivers for optical communication and signal processing. With an ongoing miniaturization of photonic circuitries, an outstanding aim is to demonstrate an on-chip, ultra-compact, electro-optic modulator without sacrificing bandwidth and modulation strength. While silicon-based electro-optic modulators have been demonstrated, they require large device footprints of the order of millimeters as a result of weak non-linear electro-optical properties. The modulation strength can be increased by deploying a high-Q resonator, however with the trade-off of significantly sacrificing bandwidth. Furthermore, design challenges and temperature tuning limit the deployment of such resonance-based modulators. Recently, novel materials like graphene have been investigated for electro-optic modulation applications with a 0.1 dB per micrometer modulation strength, while showing an improvement over pure silicon devices, this design still requires device lengths of tens of micrometers due to the inefficient overlap between the thin graphene layer, and the optical mode of the silicon waveguide. Here we experimentally demonstrate an ultra-compact, silicon-based, electro-optic modulator with a record-high 1 dB per micrometer extinction ratio over a wide bandwidth range of 1 μm in ambient conditions. The device is based on a plasmonic metal-oxide-semiconductor (MOS) waveguide, which efficiently concentrates the optical modes’ electric field into a nanometer thin region comprised of an absorption coefficient-tuneable indium-tin-oxide (ITO) layer. The modulation mechanism originates from electrically changing the free carrier concentration of the ITO layer which dramatically increases the loss of this MOS mode. The seamless integration of such a strong optical beam modulation into an existing silicon-on-insulator platform bears significant potential towards broadband, compact and efficient communication links and circuits.

The hybrid structures of graphene with semiconductor materials based on photogating effect have attracted extensive interest in recent years due to the ultrahigh responsivity. However, the responsivity (or gain) was increased at the expense of response time. In this paper, we devise a mechanism which can obtain an enhanced responsivity and fast response time simultaneously by manipulating the photogating effect (MPE). This concept is demonstrated by using a graphene/silicon-on-insulator (GSOI) hybrid structure. An ultrahigh responsivity of more than 10  A/W and a fast response time of 90 µs were obtained. The specific detectivity D was measured to be 1.46 ⨯ 10  Jones at a wavelength of 532 nm. The Silvaco TCAD modeling was carried out to explain the manipulation effect, which was further verified by the GSOI devices with different doping levels of graphene in the experiment. The proposed mechanism provides excellent guidance for modulating carrier distribution and transport, representing a new route to improve the performance of graphene/semiconductor hybrid photodetectors.

Silicon (Si), as a quasi-essential element, has a vital role in alleviating the damaging effects of various environmental stresses on plants. Cadmium (Cd) stress is severe abiotic stress, especially in acidic ecological conditions, and Si can demolish the toxicity induced by Cd as well as acidic pH on plants. Based on these hypotheses, we demonstrated 2-repeated experiments to unfold the effects of Si as silica gel on the root morphology and physiology of wheat seedling under Cd as well as acidic stresses. For this purpose, we used nine treatments with three levels of Si nanoparticles (0, 1, and 3 mmol L −1 ) derived from sodium silicate (Na 2 SiO 3 ) against three concentrations of Cd (0, 50, and 200 µmol L −1 ) in the form of cadmium chloride (CdCl 2 ) with three replications were arranged in a complete randomized design. The pH of the nutrient solution was adjusted at 5. The averages of three random replications showed that the mutual impacts of Si and Cd in acidic pH on wheat roots depend on the concentrations of Si and Cd. The collective or particular influence of low or high levels of Si (1 or 3 mM) and acidic pH (5) improved the development of wheat roots, and the collective influence was more significant than that of a single parallel treatment. The combined effects of low or high concentrations of Cd (50 or 200 µM) and acidic pH significantly reduced root growth and biomass while increased antioxidants, and reactive oxygen species (ROS) contents. The incorporation of Si (1 or 3 mmol L −1 ) in Cd-contaminated acidic nutrient solution promoted the wheat root growth, decreased ROS contents, and further increased the antioxidants in the wheat roots compared with Cd single treatments in acidic pH. The demolishing effects were better with a high level of Si (3 mM) than the low level of Si (1 Mm). In conclusion, we could suggest Si as an effective beneficial nutrient that could participate actively in several morphological and physiological activities of roots in wheat plants grown under Cd and acidic pH stresses.

We demonstrate structural color generation in silicon-on-insulator wafers using nanosecond laser irradiation. Laser-induced periodic surface structures on the thin Si film act as grating couplers, enabling optical resonances that produce bright, spectrally selective structural colors at visible wavelengths. The mechanism combines grating-mediated waveguide coupling with Fabry-Perot spectral filtering, yielding optical characteristics resembling guided-mode resonance. The central wavelength is tunable across the visible spectrum by varying Si film thickness (50-70 nm range), with measured samples exhibiting green coloration at 55 nm and red at 70 nm thickness. Numerical simulations qualitatively reproduce the observed optical properties. This non-chemical, non-fading coloration offers potential applications in secure marking and process control for semiconductor manufacturing.

This work presents a silicon-on-insulator (SOI) refractive index sensor based on a coupled resonator optical waveguide (CROW) architecture employing two inversely coupled Sagnac loop reflectors (SLRs) connected through a self-coupled feedback waveguide. The structure exploits bidirectional propagation and discrete–continuum interference to produce sharp Fano-type asymmetric resonances with steep spectral slopes, enabling enhanced wavelength sensitivity. Numerical analysis demonstrates that tuning the loop radius, directional-coupler length, coupling gap, and feedback-path length provides precise control over free spectral range (FSR), resonance asymmetry, and spectral sharpness. The sensor exhibits consistent and monotonic resonance shifts for refractive index variations from 1.33 to 1.36, with sensitivities ranging from 106 to 120 nm/RIU for the ridge feedback configuration. Sensitivity is further improved by introducing a subwavelength grating (SWG) segment into the feedback waveguide, which enhances evanescent-field interaction and increases the overlap factor without compromising compactness or Fano asymmetry. The SWG-assisted design attains sensitivities of 185.8–212.2 nm/RIU, nearly doubling sensitivity. The proposed coupled-SLR CROW provides a compact footprint, high-Q resonances, and flexible spectral engineering through accessible geometric parameters. These characteristics highlight the potential of the coupled-SLR and SWG-enhanced CROW as a promising platform for high-resolution, photonic refractive index sensing applications on SOI.

We present predictive simulations for a novel mid-infrared (MIR) polarization splitter and rotator (PSR) design. It operates in the 3.1–3.6 m range, which is crucial for applications such as chemical and biological sensing, and environmental monitoring. This is the first report of a MIR PSR in this range on a SOI platform, enabling the generation of TE modes at both ports of the PSR. Our solution is particularly important since quantum cascade lasers are the optimal choice of source in the MIR, emitting linearly polarized light in the vertical direction that couples to transverse magnetic (TM) waveguide modes, necessitating conversion to transverse electric (TE) mode for compatibility with numerous on-chip devices optimized for TE mode. Our proposed PSR is designed to provide both TE modes at both ports of the bifurcated waveguide, showcasing outstanding performance characterized by low insertion loss, low TM to TE power conversion loss, and minimal crosstalk. It exhibits TE insertion loss and TM to TE power conversion loss of less than 0.5 dB over a 500 nm and 400 nm wavelength range, respectively, while maintaining crosstalk values below 20 dB over a broad wavelength range of 400 nm.