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Broadband light-trapping enhancement of graphene absorptivity
摘要： Low optical absorptivity of graphene limits the quantum efficiency of graphene-based optoelectronic devices. We demonstrate a broadband enhancement of absorptivity in an architecture of graphene intercalation inside a simple-cubic woodpile photonic crystal. Significant light-trapping effect is achieved due to spectrally broad and dense resonances in the architecture, especially modes propagating nearly parallel to the interface between the photonic crystal and the background material. We demonstrate an overall absorptivity ～10 to 17 times larger than the free-standing bare graphene monolayer with bandwidth to central frequency ratio 0.3, and ～5 to 11 times larger with bandwidth to central frequency ratio 1.33. A distributed intercalation of three graphene monolayers proves a ～70% overall absorptivity with bandwidth to central frequency ratio 0.3.
关键词： absorptivity,broadband enhancement,graphene,light trapping,photonic crystal
更新于2025-09-23 15:23:52
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Complete trapping of light with asymmetric plasmonic resonator arrays
摘要： Trapping/absorption of light in metallic micro/nano-structures on a dielectric-interspaced metal layer were widely studied, but discrepancies in results suggests uncertainty in its perfectness. Here we propose a modified structure with asymmetric resonance elements in each unit cell for complete trapping/absorption of light. In principle, the coupled asymmetric resonators oscillate anti-symmetrically under a critical matching condition, such that leaky radiations from the resonance elements are fully canceled in the far field, which results in guaranteed complete trapping/absorption of light in the near field. The structure may be applied in optoelectronic and bio-chemical sensing devices for strong light–matter interactions.
关键词： plasmonic resonator arrays,light trapping,optoelectronic devices,bio-chemical sensing,asymmetric resonators
更新于2025-09-23 15:21:01
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Light trapping for photovoltaic cells used for optical power transmission
摘要： Photovoltaic (PV) cells used for optical power transmission convert laser light incident from limited directions to electricity. This illumination condition is in contrast to that for solar cells. A combination of an angular selective filter consisting of a dielectric multilayer on the front surface and a diffuse reflector on the rear surface significantly traps both the incident laser light into and radiation from the PV cell. This light trapping effect can improve the monochromatic conversion efficiency of a GaAs PV cell by 9% (absolute) compared with that for the ×4n2 trapping, under 872 nm and 1 W cm?2 laser illumination.
关键词： GaAs,light trapping,conversion efficiency,optical power transmission,photovoltaic cells
更新于2025-09-23 15:21:01
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High-Performance Enhancement of a GaAs Photodetector Using a Plasmonic Grating
摘要： In this study, we present and establish a gold surface plasmon polariton (SPP) GaAs photodetector that achieves high internal quantum efficiency (IQE). At a wavelength of 600 nm, the IQE with the SPP was 85%, while the IQE without the SPP was 42%, an enhancement of 43%. Also, at a wavelength of 675 nm, the IQE with SPP was 82%, whereas the IQE without SPP was 45%, which constitutes an increase of 37%. Such excellent performance is ascribed to the subwavelength scope of the optical power in the photoconductive-based gold SPP GaAs that provides high IQE. Moreover, the recombination of the SPP in the photodetector provides greater photocurrent and responsivity.
关键词： Surface plasmon polaritons,GaAs photodetector,Plasmonic photodetectors,Light trapping,Plasmonic grating
更新于2025-09-23 15:21:01
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Surface Modifications for Light Trapping in Silicon Heterojunction Solar Cells: A Brief Review
摘要： Reducing crystalline silicon (c-Si) wafer thickness is an effective method to reduce the fabrication cost as it constitutes a major portion of the photovoltaic module cost. However, the open-circuit voltage and fill factor depend on the wafer thickness; further, the short-circuit current density (JSC), affects the device performance negatively. Therefore, light trapping is vital for increasing the JSC of Si solar cells. Consequently, it is essential for improving the conversion efficiency of the solar cell and reduce its production cost by decreasing the wafer thickness. It can be assumed that the thickness of the Si wafer will gradually achieve a minimum value of ~ 100?μm in the future. Therefore, reducing the as-cut wafer thickness will result in a more efficient use of Si. This paper reports the surface modification for light trapping based on the Si solar cell application. Additionally, we introduce methods for surface modification, such as front-side texturing and rear-side polishing.
关键词： Texturing,Polishing,Si solar cell,Surface modification,Light trapping,High efficiency
更新于2025-09-23 15:21:01
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A Si-based InP/InGaAs nanowire array photodetector operating at telecommunication wavelength
摘要： A Si-based vertical nanowire heterostructure array photodetector is designed and studied by a coupled three-dimensional optoelectronic simulation. Each nanowire is composed of an InP/In0.53Ga0.47As/InP axial p-i-n junction, which is designed to operate at telecommunication wavelengths. The results show that the absorption of the nanowire array strongly depends on the D/P ratio and nanowire diameter. By tuning the D/P ratio and diameter simultaneously, the peak absorption wavelength could be fixed at 1550 nm. Due to the light-trapping and light-concentrating properties, the nanowire array photodetector exhibits a remarkable responsivity beyond 0.8 A/W, several times higher than its thin film counterpart with the equivalent thickness. This work suggests that the III-V nanowire array is promising for high-performance Si-based photodetectors applied in optical telecommunication systems.
关键词： Nanowire array,Light-trapping,Optical communication,Si-based,InGaAs/InP
更新于2025-09-23 15:21:01
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Light trapping induced flexible wrinkled nanocone SERS substrate for highly sensitive explosive detection
摘要： We reported an ultrasensitive TNT detection method via a novel light trapping induced wrinkled nanocone flexible SERS substrate, which was fabricated by colloidal lithography and oxygen plasma etching on transparent PET film. Especially, a set of nanowrinkles with 50-60nm was found on the sidewall of nanocone after etching. By coating 30nm gold film, this flexible SERS substrate provided uniform hot spots, which demonstrated high reproducibility and sensitivity. 4-ATP molecules based Meisenheimer complex, which is a well-known charge-transfer interaction between electron-poor TNT and electron-rich amino group, was taken to detect ultra-low concentration of TNT explosive. The Raman signal of TNT was significantly enhanced by charge-transfer, light trapping effect and coupled electromagnetic field. The detection sensitivity of TNT molecules was as low as 10-13mol/L, and show a good linear response in the range from 10-8 to 10-13mol/L. Consequently, by brushing this flexible SERS substrate onto a cloth bag, trace amount of TNT residues with concentration as low as 10-10mol/L can be easily analyzed. It is believed that the proposed highly sensitive and uniform flexible substrate provides a significant solution for trace analysis of TNT residue in criminal forensic, military and security check.
关键词： Nanowrinkle,Nanocone,Flexible materials,Light trapping,SERS
更新于2025-09-23 15:21:01
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Visualizing light trapping within textured silicon solar cells
摘要： Random pyramids are the most widely used texture in commercial monocrystalline silicon solar cells to trap weakly absorbed photons with near-bandgap energies. There has been steady improvement in efforts to model the light-trapping performance of random pyramids, including a shift from an assumed pyramid base angle of 54.7° (ideal-random pyramids) to smaller values that are consistent with measured average angles. However, simulations have not yet considered the effects of a distribution of base angles (real-random pyramids), which all real textured wafers have. In this contribution, we benchmark the light-trapping capability of real-random pyramids against ideal-random pyramids and Lambertian scatterers by performing ray tracing of an accurate three-dimensional topographical map of the surface of a textured silicon wafer measured using atomic force microscopy. The angular distribution function (ADF) of light rays within the wafer, calculated at each pass as rays bounce between the front and rear surfaces, reveals that real-random pyramids are superior to ideal-random pyramids in trapping light precisely because of the distribution in their base angle. In particular, the ADF inside a wafer with real-random pyramids evolves to be Lambertian within just two passes—by the time (non-absorbed) light re-arrives at the front surface. Furthermore, the total path-length enhancement of light reaches nearly 60—exceeding that of a wafer with Lambertian surfaces—for narrow angles of incidence, though it falls short of the Lambertian reference for oblique angles.
关键词： atomic force microscopy,random pyramids,silicon solar cells,light trapping,Lambertian scatterers,ray tracing
更新于2025-09-23 15:19:57
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Improving light harvesting and charge extraction of polymer solar cells upon buffer layer doping
摘要： It is an important strategy to improve the performance of polymer solar cells (PSCs) by incorporating metal nanoparticles into functional layers. Herein, gold (Au)@titanium dioxide (TiO2) plasmonic core-shell nanoparticles (PCSNPs) are synthesized and doped into zinc oxide (ZnO) as hybrid electron transport layer in PSCs. Improved light trapping and electrical conductivity are achieved through localized surface plasma resonance of Au@TiO2 PCSNPs. As a result, the short-circuit current density is apparently enhanced, while remaining the unchanged open-circuit voltage. The maximum PCE of 8.801% is obtained when 1.5 wt% Au@TiO2 PCSNPs are introduced into the ZnO layer. This study provides a new inspiration for the development of high efficiency PSCs.
关键词： Surface plasmon resonance,charge transport,Au@TiO2 PCSNPs,Light trapping,Electrical conductivity
更新于2025-09-23 15:19:57
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Broadband high responsivity large-area plasmonic-enhanced multilayer MoS <sub/>2</sub> on p-type silicon photodetector using Au nanostructures
摘要： High responsivity, large-area plasmonic-enhanced nanostructure photodetector based on multilayer (ML) molybdenum disulfide (MoS2) deposited on p-type Silicon (Si) substrates is reported. A large area ML-MoS2 is deposited onto the Si photodetector (PD) using a modified membrane filtration method. This large area ML-MoS2 and Au NSs on the p-Si form a cavity-like structure that dramatically enhances the incident light path. The increase of incident light path due to light trapping effect enhances the electron-hole pair generation tremendously. The plasmonic-enhanced ML MoS2 on Si PD has achieved a stable and repeatable photoresponse up to 37 A W?1, whereas the detectivity is around 1012 Jones at the broad wavelengths (405–780 nm) with a modulation frequency of 1 kHz. The enhancement of photoresponsivity is 8, 5.3 and 11 times with 5 V bias at an incident wavelength of 405 nm, 650 nm and 780 nm respectively as compared to the bare p-Si PD. The experimental results also show that the plasmonic-enhanced ML-MoS2 on Si PD exhibited fast photoresponse (rise time of ～1 μs and fall time of ～18 μs), which is much higher compared to typical transition metal dichalcogenide PD or single layer MoS2 based PD. These excellent performances show that the plasmonic-enhanced MoS2 structure is highly potential to apply in Si photovoltaics, visible range photodetection, and visible bio/chemical sensing application.
关键词： light trapping,photodetectors,optical surface waves,nanostructured materials
更新于2025-09-23 15:19:57