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AIP Conference Proceedings [Author(s) SILICONPV 2018, THE 8TH INTERNATIONAL CONFERENCE ON CRYSTALLINE SILICON PHOTOVOLTAICS - Lausanne, Switzerland (19–21 March 2018)] - Understanding the optics of industrial black silicon
摘要： Industrial scale black silicon texturing has become a topic of increasing importance as a method for enabling lower cost multicrystalline silicon wafers through diamond wire sawing, as well as for its potential to provide improved efficiencies through enhanced optical characteristics. Two different texturing processes have emerged as candidates for mainstream industrial uptake, metal catalyzed chemical etching (MCCE) and reactive ion etching (RIE). However, these techniques can produce substantially different textures and both provide a wide parameter space allowing for various feature shapes and sizes to be produced. The surface texture not only determines the total reflectance of a solar cell, but also impacts the light trapping and subsequent absorption through scattering. Here, we carry out a detailed analysis on a representative range of both MCCE and RIE textures on multiple substrate types in order to further develop the fundamental understanding of how these specific surface morphologies impact the optical characteristics. This will better enable integration with other process conditions as well as optimization between optical and electrical requirements.
关键词： black silicon,surface morphology,RIE,MCCE,optical characteristics
更新于2025-10-22 19:40:53
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Fabrication of Nano-Structured V-Shaped Grooves on B-Si Wafer for On-Board Spaceborne Blackbody System
摘要： Nano-structured V-shaped grooves on the black-silicon (B-Si) was fabricated to improve the optical emissivity for on-board spaceborne blackbody system. The deep reactive ion etching (DRIE) process was used to fabricate the V-shaped grooves on the B-Si wafer according to the etching conditions. The scanning electron microscopy (SEM) and infrared (IR) spectroscopy were used to evaluate the morphology, aspect ratio, and reflectance of the fabricated B-Si specimen. The surface of the B-Si was successfully structured with the nano-scale V-shaped grooves of which the height and diameter were approximately 670 nm and 200 nm, respectively. The reflectance of the B-Si was close to zero in a wavelength less than 1 μm. As a result, the fabricated B-Si with the nano-structured V-shaped grooves was suitable to the blackbody target for on-board spaceborne blackbody system.
关键词： On-Board Calibration,V-Shaped Groove,DRIE Process,Blackbody,Black Silicon
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field emission behavior of single n- and p-type black Si pillar structures
摘要： We have investigated the properties of single n- and p-type black silicon (b-Si) pillars with a height of 20 μm under strong electric field and halogen lamp or laser illumination. For both type of b-Si pillar structures, I-V measurements revealed strong activation effects, which consisted in sudden current increases during the first up/down voltage sweeps. The maximum reproducible emission current from a single n-type b-Si pillar structure was about 15 μA. A pronounced saturation region at 240 nA was observed for a single p-type b-Si pillar. The current fluctuation over time showed a standard deviation of 28 % and 2.5 % for n- and p-type single b-Si pillar structures, respectively. Optical switching under halogen lamp illumination resulted in at least 3 times higher saturation currents and showed a linear dependence of the FE current on the laser power.
关键词： black silicon,photoemission,field emission
更新于2025-09-23 15:21:21
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Silicon quantum dot/black silicon hybrid nanostructure for broadband reflection reduction
摘要： The incorporation of silicon quantum dots (Si QDs) onto black silicon (b-Si) as a hybrid nanostructure has resulted in reflectance reduction over a wide spectral range (300–1000 nm). Si QDs were derived from porous Si (P–Si) by anodic electrochemical etching and ultrasonication whereas b-Si was fabricated by the two-step metal assisted chemical etching (MACE) technique. Si QDs with average diameter of 1.8 ?1.1 nm are suitable for photon down-conversion of UV light (365 nm) into the visible (665 and 740 nm). As a hybrid nanostructure, smaller sized Si QDs exhibited better surface coverage on the b-Si nanopillar sidewalls resulting in enhanced broadband reflection reduction, particularly at 600 nm and beyond. At wavelength of 600 nm, the Si QD/b-Si nanostructure exhibited a reflectance reduction from 9.9% to 6.5% with a more pronounced reduction towards the longer wavelengths, attributed to refractive index matching and optical confinement within the Si nanostructure. Photocurrent enhancement in the UV-blue excitation region is attributed to photon down-conversion (UV to visible) by Si QDs to the underlying b-Si.
关键词： Photon down-conversion,Broadband reflection reduction,Black silicon,Quantum dot
更新于2025-09-23 15:19:57
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High-Performance Free-Standing Flexible Photodetectors Based on Sulfur-Hyperdoped Ultrathin Silicon
摘要： Flexible photodetectors (PDs) prepared with silicon-based materials have received considerable attention for use in a wide range of portable and wearable applications. In this study, we present the first free-standing flexible PD based on sulfur-hyperdoped ultrathin silicon, which was fabricated using a femtosecond laser in SF6 atmosphere. It is found that the fabricated device exhibits excellent performance of broadband photoresponse from 400 to 1200 nm, with peak responsivity of 63.79 A/W @ 870 nm at a low bias voltage of -2 V, corresponding to an external quantum efficiency reaching 9092%, which surpasses most values reported for silicon-based flexible PDs. In addition, the device shows a fast response speed (rise time τr=68 μs) and stable detection performance with good mechanical flexibility. The high-performance PD described here suggests a promising way in flexible applications for sensors, imaging systems, and optical communication systems.
关键词： flexible photodetector,ultrathin silicon,black silicon,sulfur-hyperdoped,femtosecond laser
更新于2025-09-19 17:13:59
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Engineering the crystalline silicon surface by femtosecond laser processing in liquid: hierarchical micro/nanostructure and amorphization
摘要： Hierarchical micro/nanostructure surface structures with different spatial characteristics are achieved after irradiation of crystalline silicon via femtosecond (fs) laser pulses (800 nm, 120 fs, 1 kHz) with the sample submerged in ethanol. According to laser pulse energy and fabrication parameters (such as scanning speed and superimposing writing), a characteristic morphology evolution of ovoid-like smooth modified area, ripple-like, wave-like, and coral-like micro/nanostructures is demonstrated, and the underline principle is discussed. The amorphization of fs laser-modified area is verified and investigated by Raman spectroscope. These modified structures have potential applications in sensors, silicon photovoltaic cells, and sterilization.
关键词： topographical surface alterations,black silicon,laser ablation in liquid,femtosecond phenomena
更新于2025-09-19 17:13:59
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Broadband Anti-Reflection in Black Silicon Fabricated by Two-Step Silver-Assisted Wet Chemical Etching for Photovoltaics
摘要： This paper reports broadband anti-reflection in black silicon (b-Si) fabricated by two-step metal-assisted chemical etching (MACE) for potential photovoltaic (PV) applications. The method involves deposition of silver nanoparticles (Ag NPs) in aqueous solution of HF:AgNO3, followed by etching in HF:H2O2:DI H2O solution for different duration (10-25 s). Effects of etching time towards surface morphological and optical properties of b-Si nanowires are investigated. Surface morphological characterization confirms presence of b-Si nanowires with heights of 350-570 nm and diameter of 150-300 nm. The b-Si nanowires exhibit outstanding broadband anti-reflection due to refractive index grading effect. This is represented as weighted average reflection (WAR) in the 300-1100 nm wavelength region. After 20 s of etching, b-Si nanowires with height of 570 nm and width of about 200 nm are produced. The nanowires demonstrate WAR of 5.5%, which represents the lowest WAR in this investigation. This results in absorption of 95.6% at wavelength of 600 nm. The enhanced broadband light absorption yields maximum potential short-circuit current density (Jsc(max)) of up to 39.7 mA/cm2, or 51% enhancement compared to c-Si reference. This facile b-Si fabrication method for broadband enhanced anti-reflection could be a promising technique to produce potential PV devices with high photocurrent.
关键词： black silicon,nanowires,silver-assisted etching,refractive index grading,anti-reflection
更新于2025-09-19 17:13:59
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Light Confinement Effect Induced Highly Sensitive, Self‐Driven Near‐Infrared Photodetector and Image Sensor Based on Multilayer PdSe <sub/>2</sub> /Pyramid Si Heterojunction
摘要： In this study, a highly sensitive and self-driven near-infrared (NIR) light photodetector based on PdSe2/pyramid Si heterojunction arrays, which are fabricated through simple selenization of predeposited Pd nanofilm on black Si, is demonstrated. The as-fabricated hybrid device exhibits excellent photoresponse performance in terms of a large on/off ratio of 1.6 × 105, a responsivity of 456 mA W?1, and a high specific detectivity of up to 9.97 × 1013 Jones under 980 nm illumination at zero bias. Such a relatively high sensitivity can be ascribed to the light trapping effect of the pyramid microstructure, which is confirmed by numerical modeling based on finite-difference time domain. On the other hand, thanks to the broad optical absorption properties of PdSe2, the as-fabricated device also exhibits obvious sensitivity to other NIR illuminations with wavelengths of 1300, 1550, and 1650 nm, which is beyond the photoresponse range of Si-based devices. It is also found that the PdSe2/pyramid Si heterojunction device can also function as an NIR light sensor, which can readily record both “tree” and “house” images produced by 980 and 1300 nm illumination, respectively.
关键词： optoelectronic devices,near-infrared light,light manipulation,black silicon,2D materials
更新于2025-09-19 17:13:59
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Low Reflection and Low Surface Recombination Rate Nano-Needle Texture Formed by Two-Step Etching for Solar Cells
摘要： In this study, needle-like and pyramidal hybrid black silicon structures were prepared by performing metal-assisted chemical etching (MACE) on alkaline-etched silicon wafers. E?ects of the MACE time on properties of the black silicon wafers were investigated. The experimental results showed that a minimal re?ectance of 4.6% can be achieved at the MACE time of 9 min. The height of the nanostructures is below 500 nm, unlike the height of micrometers needed to reach the same level of re?ectance for the black silicon on planar wafers. A stacked layer of silicon nitride (SiNx) grown by inductively-coupled plasma chemical vapor deposition (ICPCVD) and aluminum oxide (Al2O3) by spatial atomic layer deposition was deposited on the black silicon wafers for passivation and antire?ection. The 3 min MACE etched black silicon wafer with a nanostructure height of less than 300 nm passivated by the SiNx/Al2O3 layer showed a low surface recombination rate of 43.6 cm/s. Further optimizing the thickness of ICPCVD-SiNx layer led to a re?ectance of 1.4%. The hybrid black silicon with a small nanostructure size, low re?ectance, and low surface recombination rate demonstrates great potential for applications in optoelectronic devices.
关键词： passivation,black silicon,metal-assisted chemical etching
更新于2025-09-16 10:30:52
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MoSx quantum dots modified black silicon for high efficient photoelectrochemical hydrogen evolution
摘要： Nanostructured black silicon (bSi) is widely used for solar water splitting application due to the excellent light-harvesting properties and large surface area-to-volume ratio that favors photoelectrochemical reactions. However, bSi suffers from low catalytic activity, owing to its poor charge transfer kinetics during hydrogen evolution process. In this work, we developed a novel photoelectrode by incorporating molybdenum sulfide (MoSx) quantum dots on the surface of black silicon. The synergetic effect of MoSx and bSi significantly enhance the activity for hydrogen evolution reaction. An onset potential of 0.255 VRHE, a high short-circuit photocurrent density (Jsc) of 12.2 mA·cm-2, and a hydrogen evolution rate of 226.5 μmol·h-1·cm-2 have been achieved.
关键词： photocathode,Black silicon,MoSx quantum dots,hydrogen evolution reaction
更新于2025-09-12 10:27:22