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Li Y, Wang D, Liang Z, Zeng L, Li W, Xie P, Ding Q, Zhang H, Schaaf P, Wang W. Evaluating the Optical Response of Heavily Decorated Black Silicon Based on a Realistic 3D Modeling Methodology. ACS APPLIED MATERIALS & INTERFACES 2022; 14:36189-36199. [PMID: 35767685 DOI: 10.1021/acsami.2c05652] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Combining black silicon (BS), a nanostructured silicon containing highly roughened surface morphology with plasmonic materials, is becoming an attractive approach for greatly enhancing light-matter interactions with promising applications of sensing and light harvesting. However, precisely describing the optical response of a heavily decorated BS structure is still challenging due to the increasing complexity in surface morphology and plasmon hybridization. Here, we propose and fully characterize BS-based multistacked nanostructures with randomly distributed nanoparticles on the highly roughened nonflat surface. We demonstrate a realistic 3D modeling methodology based on parametrized scanning electron microscopy images that provides high-precision morphology details, successfully linking the theoretical analysis with experimental optical response of the complex nanostructures. Far-field calculations very nicely reproduce experimental reflectance spectra, revealing the dependency of light trapping on the thickness of the conformal reflector and the atop nanoparticle size. Near-field analysis clearly identifies three types of stochastic "hotspots". Their contribution to the overall field enhancement is shown to be very much sensitive to the nanoscale surface morphology. The simulated near-field property is then used to examine the measured surface-enhanced Raman scattering (SERS) response on the multistacked structures. The present modeling approach combined with spectroscopic characterizations is expected to offer a powerful tool for the precise description of the optical response of other large-scale highly disordered realistic 3D systems.
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Affiliation(s)
- Yuhang Li
- College of Physics, Sichuan University, Chengdu 610064, China
| | - Dong Wang
- Institute for Micro and Nanotechnologies MacroNano(R) and Institute for Materials Science and Engineering, Chair of Materials for Electrical Engineering and Electronics, Technische Universität Ilmenau, 98693 Ilmenau, Germany
| | - Zhengchen Liang
- College of Physics, Sichuan University, Chengdu 610064, China
- Department of Physics, Tsinghua University, Beijing 100084, P. R. China
| | - Lingxiao Zeng
- College of Physics, Sichuan University, Chengdu 610064, China
| | - Wenxue Li
- College of Physics, Sichuan University, Chengdu 610064, China
| | - Peng Xie
- College of Physics, Sichuan University, Chengdu 610064, China
| | - Qi Ding
- College of Physics, Sichuan University, Chengdu 610064, China
| | - Hong Zhang
- College of Physics, Sichuan University, Chengdu 610064, China
- Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065, China
| | - Peter Schaaf
- Institute for Micro and Nanotechnologies MacroNano(R) and Institute for Materials Science and Engineering, Chair of Materials for Electrical Engineering and Electronics, Technische Universität Ilmenau, 98693 Ilmenau, Germany
| | - Wei Wang
- College of Physics, Sichuan University, Chengdu 610064, China
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2
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Anti-Reflection Nanostructures on Tempered Glass by Dynamic Beam Shaping. MICROMACHINES 2021; 12:mi12030289. [PMID: 33803433 PMCID: PMC8000063 DOI: 10.3390/mi12030289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 02/27/2021] [Accepted: 03/08/2021] [Indexed: 11/24/2022]
Abstract
Reflectivity and surface topography of tempered glass were modified without any thermal damage to the surroundings by utilizing 1.7 ps ultrashort pulsed laser on its fundamental wavelength of 1030 nm. To speed up the fabrication, a dynamic beam shaping unit combined with a galvanometer scanning head was applied to divide the initial laser beam into a matrix of beamlets with adjustable beamlets number and separation distance. By tuning the laser and processing parameters, reflected intensity can be reduced up to 75% while maintaining 90% of transparency thus showing great potential for display functionalization of mobile phones or laptops.
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Gawlik B, Barrera C, Yu ET, Sreenivasan SV. Hyperspectral imaging for high-throughput, spatially resolved spectroscopic scatterometry of silicon nanopillar arrays. OPTICS EXPRESS 2020; 28:14209-14221. [PMID: 32403464 DOI: 10.1364/oe.388158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/23/2020] [Indexed: 06/11/2023]
Abstract
Modern high-throughput nanopatterning techniques, such as nanoimprint lithography, make it possible to fabricate arrays of nanostructures (features with dimensions of 10's to 100's of nm) over large area substrates (cm2 to m2 scale) such as Si wafers, glass sheets, and flexible roll-to-roll webs. The ability to make such large-area nanostructure arrays (LNAs) has created an extensive design space, enabling a wide array of applications including optical devices, such as wire-grid polarizers, transparent conductors, color filters, and anti-reflection surfaces, and building blocks for electronic components, such as ultracapacitors, sensors, and memory storage architectures. However, existing metrology methods will have trouble scaling alongside fabrication methods. Scanning electron microscopy (SEM) and atomic force microscopy (AFM), for instance, have micron scale fields of view (FOV) that preclude comprehensive characterization of LNAs, which may be manufactured at m2 per minute rates. Scatterometry approaches have larger FOVs (typically 100's of µm to a few mm), but traditional scatterometry systems measure samples one point at a time, which also makes them too slow for large-scale LNA manufacturing. In this work, we demonstrate parallelization of the traditional spectroscopic scatterometry approach using hyperspectral imaging, increasing the throughput of the technique by a factor of 106-107. We demonstrate this approach by using hyperspectral imaging and inverse modeling of reflectance spectra to derive 3-dimensional geometric data for Si nanopillar array structures over both mm and cm-scale with µm-scale spatial resolution. This work suggests that geometric measurements for a variety of LNAs can be performed with the potential for high speed over large areas which may be critical for future LNA manufacturing.
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Meng J, Cadusch JJ, Crozier KB. Detector-Only Spectrometer Based on Structurally Colored Silicon Nanowires and a Reconstruction Algorithm. NANO LETTERS 2020; 20:320-328. [PMID: 31829611 DOI: 10.1021/acs.nanolett.9b03862] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Spectroscopy is a cornerstone in the field of optics. Conventional spectrometers generally require two elements. The first provides wavelength selectivity, for example, diffraction grating or Michelson interferometer. The second is a detector (or detector array). Many applications would benefit from very small and lightweight spectrometers. This motivates us to investigate what may be regarded as an ultimate level of miniaturization for a spectrometer, in which it consists solely of a detector array. We demonstrate a chip containing 24 pixels, each comprising a silicon nanowire (Si NW) array photodetector formed above a planar photodetector. The NWs are structurally colored, enabling us to engineer the responsivity spectra of all photodetectors in the chip. Each pixel thus combines wavelength selectivity and photodetection functions. We demonstrate the use of our chip to reconstruct the spectrum of an unknown light source impinging upon it. This is achieved by an algorithm that takes as its inputs the measured photocurrents from the pixels and a library of their responsivity spectra.
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Gawlik BM, Cossio G, Kwon H, Jurado Z, Palacios B, Singhal S, Alù A, Yu ET, Sreenivasan SV. Structural coloration with hourglass-shaped vertical silicon nanopillar arrays. OPTICS EXPRESS 2018; 26:30952-30968. [PMID: 30469985 DOI: 10.1364/oe.26.030952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 10/07/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate that arrays of hourglass-shaped nanopillars patterned into crystalline silicon substrates exhibit vibrant, highly controllable reflective structural coloration. Unlike structures with uniform sidewall profiles, the hourglass profile defines two separate regions on the pillar: a head and a body. The head acts as a suspended Mie resonator and is responsible for resonant reflectance, while the body acts to suppress broadband reflections from the surface. The combination of these effects gives rise to vibrant colors. The size of the nanopillars can be tuned to provide a variety of additive colors, including the RGB primaries. Experimental results are shown for nanopillar arrays fabricated using nanoimprint lithography and plasma etching. A finite difference time domain (FDTD) model is validated against these results and is used to elucidate the electromagnetic response of the nanopillars. Furthermore, a COMSOL model is used to investigate the angle dependence of the reflectance. In view of display applications, a genetic algorithm is used to optimize the nanopillar geometries for RGB color reflective pixels, showing that nearly all of the sRGB color space and most of the Adobe RGB color space can be covered with this technique.
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Zhong H, Ilyas N, Song Y, Li W, Jiang Y. Enhanced near-infrared absorber: two-step fabricated structured black silicon and its device application. NANOSCALE RESEARCH LETTERS 2018; 13:316. [PMID: 30306413 PMCID: PMC6179974 DOI: 10.1186/s11671-018-2741-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/01/2018] [Indexed: 06/08/2023]
Abstract
Silicon is widely used in semiconductor industry but has poor performance in near-infrared photoelectronic devices because of its high reflectance and band gap limit. In this study, two-step process, deep reactive ion etching (DRIE) method combined with plasma immersion ion implantation (PIII), are used to fabricate microstructured black silicon on the surface of C-Si. These improved surfaces doped with sulfur elements realize a narrower band gap and an enhancement of light absorptance, especially in the near-infrared range (800 to 2000 nm). Meanwhile, the maximum light absorptance increases significantly up to 83%. A Si-PIN photoelectronic detector with microstructured black silicon at the back surface exhibits remarkable device performance, leading to a responsivity of 0.53 A/W at 1060 nm. This novel microstructured black silicon, combining narrow band gap characteristic, could have a potential application in near-infrared photoelectronic detection.
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Affiliation(s)
- Hao Zhong
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 China
| | - Nasir Ilyas
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054 China
| | - Yuhao Song
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054 China
| | - Wei Li
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 China
| | - Yadong Jiang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 China
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Wei B, Tang Z, Wang S, Qin C, Li C, Ding X, Gao Y, Portier X, Gourbilleau F, Stiévenard D, Xu T. Enhanced photovoltaic performance of inverted polymer solar cells through atomic layer deposited Al 2O 3 passivation of ZnO-nanoparticle buffer layer. NANOTECHNOLOGY 2018; 29:395204. [PMID: 29972683 DOI: 10.1088/1361-6528/aad131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work, an atomic layer deposited (ALD) Al2O3 ultrathin layer was introduced to passivate the ZnO-nanoparticle (NP) buffer layer of inverted polymer solar cells (PSCs) based on P3HT:PCBM. The surface morphology of the ZnO-NP/Al2O3 interface was systematically analyzed by using a variety of tools, in particular transmission electron microscopy (TEM), evidencing a conformal ALD-Al2O3 deposition. The thickness of the Al2O3 layers was optimized at the nanoscale to boost electron transport of the ZnO-NP layer, which can be attributed to the suppression of oxygen vacancy defects in ZnO-NPs confirmed by photoluminescence measurement. The optimal inverted PSCs passivated by ALD-Al2O3 exhibited an ∼22% higher power conversion efficiency than the control devices with a pristine ZnO-NP buffer layer. The employment of the ALD-Al2O3 passivation layer with precisely controlled thickness provides a promising approach to develop high efficiency PSCs with novel polymer materials.
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Affiliation(s)
- Bin Wei
- Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, Shanghai, 200072, People's Republic of China
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Elmi OI, Cristini-Robbe O, Chen MY, Wei B, Bernard R, Yarekha D, Okada E, Ouendi S, Portier X, Gourbilleau F, Xu T, Stiévenard D. Local Schottky contacts of embedded Ag nanoparticles in Al 2O 3/SiN x :H stacks on Si: a design to enhance field effect passivation of Si junctions. NANOTECHNOLOGY 2018; 29:285403. [PMID: 29697055 DOI: 10.1088/1361-6528/aac032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This paper describes an original design leading to the field effect passivation of Si n+-p junctions. Ordered Ag nanoparticle (Ag-NP) arrays with optimal size and coverage fabricated by means of nanosphere lithography and thermal evaporation, were embedded in ultrathin-Al2O3/SiN x :H stacks on the top of implanted Si n+-p junctions, to achieve effective surface passivation. One way to characterize surface passivation is to use photocurrent, sensitive to recombination centers. We evidenced an improvement of photocurrent by a factor of 5 with the presence of Ag NPs. Finite-difference time-domain (FDTD) simulations combining with semi-quantitative calculations demonstrated that such gain was mainly due to the enhanced field effect passivation through the depleted region associated with the Ag-NPs/Si Schottky contacts.
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Affiliation(s)
- O Ibrahim Elmi
- Université de Djibouti, Faculté des Sciences BP 1904, Djibouti
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9
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Magdi S, El-Rifai J, Swillam MA. One step fabrication of Silicon nanocones with wide-angle enhanced light absorption. Sci Rep 2018; 8:4001. [PMID: 29507294 PMCID: PMC5838109 DOI: 10.1038/s41598-018-22100-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 02/07/2018] [Indexed: 12/02/2022] Open
Abstract
We report the fabrication of an array of random Silicon nanocones using a KrF excimer laser. A 370 nm thick amorphous Silicon layer deposited on a glass substrate was used in the process. The fabricated nanocones showed a large and broadband absorption enhancement over the entire visible wavelength range. An enhancement up to 350% is measured at λ = 650 nm. Additionally, the laser irradiation caused the nanocones to crystallize. The effect of changing the laser parameters (i.e. energy density, time, and frequency) on the morphology and the absorption is studied and compared. Wide-angle anti-reflective properties have been observed for the fabricated nanocones with less than 10% reflection for angles up to 60°. The major limitation of amorphous silicon thin film solar cells is the reduced absorption. This problem could be solved if light is trapped efficiently inside the thin film without the need of increasing the film thickness. The random array of nanocones presented in this work showed a substantial increase in absorption over a wide angle, were fabricated at a low cost and are easily scalable. This technique offers a fast approach which could significantly help in overcoming the absorption limitation.
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Affiliation(s)
- Sara Magdi
- Nanotechnology Program, American University in Cairo, AUC Avenue New Cairo, 11835, Cairo, Egypt
| | - Joumana El-Rifai
- Department of Physics, American University in Cairo, AUC Avenue New Cairo, 11835, Cairo, Egypt
| | - Mohamed A Swillam
- Nanotechnology Program, American University in Cairo, AUC Avenue New Cairo, 11835, Cairo, Egypt. .,Department of Physics, American University in Cairo, AUC Avenue New Cairo, 11835, Cairo, Egypt.
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10
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Liu HY, Das UK, Birkmire RW. Surface Defect Passivation and Reaction of c-Si in H 2S. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:14580-14585. [PMID: 29198109 DOI: 10.1021/acs.langmuir.7b03520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A unique passivation process of Si surface dangling bonds through reaction with hydrogen sulfide (H2S) is demonstrated in this paper. A high-level passivation quality with an effective minority carrier lifetime (τeff) of >2000 μs corresponding to a surface recombination velocity of <3 cm/s is achieved at a temperature range of 550-650 °C. X-ray photoelectron spectroscopy (XPS) confirmed the bonding states of Si and S and provides insights into the reaction pathway of Si with H2S and other impurity elements both during and after the reaction. Quantitative analysis of XPS spectra showed that the τeff increases with an increase in the surface S content up to ∼3.5% and stabilizes thereafter, indicative of surface passivation by monolayer coverage of S on the Si surface. However, S passivation of the Si surface is highly unstable because of thermodynamically favorable reaction with atmospheric H2O and O2. This instability can be eliminated by capping the S-passivated Si surface with a protective thin film such as low-temperature-deposited amorphous silicon nitride.
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Affiliation(s)
- Hsiang-Yu Liu
- Institute of Energy Conversion and ‡Department of Materials Science and Engineering, University of Delaware , Newark, Delaware 19716, United States
| | - Ujjwal K Das
- Institute of Energy Conversion and ‡Department of Materials Science and Engineering, University of Delaware , Newark, Delaware 19716, United States
| | - Robert W Birkmire
- Institute of Energy Conversion and ‡Department of Materials Science and Engineering, University of Delaware , Newark, Delaware 19716, United States
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FISCHER GUILLAUME, DRAHI ETIENNE, FOLDYNA MARTIN, GERMER THOMASA, JOHNSON ERIKV. Plasma nanotexturing of silicon surfaces for photovoltaics applications: influence of initial surface finish on the evolution of topographical and optical properties. OPTICS EXPRESS 2017; 25:A1057-A1071. [PMID: 29220984 PMCID: PMC5831130 DOI: 10.1364/oe.25.0a1057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/05/2017] [Indexed: 06/07/2023]
Abstract
Using a plasma to generate a surface texture with feature sizes on the order of tens to hundreds of nanometers ("nanotexturing") is a promising technique being considered to improve efficiency in thin, high-efficiency crystalline silicon solar cells. This study investigates the evolution of the optical properties of silicon samples with various initial surface finishes (from mirror polish to various states of micron-scale roughness) during a plasma nanotexturing process. It is shown that during said process, the appearance and growth of nanocone-like structures are essentially independent of the initial surface finish, as quantified by the auto-correlation function of the surface morphology. During the first stage of the process (2 min to 15 min etching), the reflectance and light-trapping abilities of the nanotextured surfaces are strongly influenced by the initial surface roughness; however, the differences tend to diminish as the nanostructures become larger. For the longest etching times (15 min or more), the effective reflectance is less than 5% and a strong anisotropic scattering behavior is also observed for all samples, leading to very elevated levels of light-trapping.
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Affiliation(s)
- GUILLAUME FISCHER
- Institut Photovoltaïque d’Ile-de-France (IPVF), 8 rue de la Renaissance, 92160 Antony, France
- LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France
| | - ETIENNE DRAHI
- Total S.A. Renewables, 2 place Jean Millier, 92078 Paris La Défense Cedex, France
| | - MARTIN FOLDYNA
- LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France
| | | | - ERIK V. JOHNSON
- LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France
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Fan R, Mao J, Yin Z, Jie J, Dong W, Fang L, Zheng F, Shen M. Efficient and Stable Silicon Photocathodes Coated with Vertically Standing Nano-MoS 2 Films for Solar Hydrogen Production. ACS APPLIED MATERIALS & INTERFACES 2017; 9:6123-6129. [PMID: 28128543 DOI: 10.1021/acsami.6b15854] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Water splitting in a photoelectrochemical cell, which converts sunlight into hydrogen energy, has recently received intense research. Silicon is suitable as a viable light-harvesting material for constructing such cell; however, there is a need to improve its stability and explore a cheap and efficient cocatalyst. Here we fabricate highly efficient and stable photocathodes by integrating crystalline MoS2 catalyst with ∼2 nm Al2O3 protected n+p-Si. Al2O3 acts as a protective and passivative layer of the Si surface, while the sputtering method using a MoS2 target along with a postannealing leads to a vertically standing, conformal, and crystalline nano-MoS2 layer on Al2O3/n+p-Si photocathode. Efficient (0.4 V vs RHE onset potential and 35.6 mA/cm2 saturated photocurrent measured under 100 mA/cm2 Xe lamp illumination) and stable (above 120 h continuous water splitting) photocathode was obtained, which opens the door for the MoS2 catalyst to be applied in photoelectrochemical hydrogen evolution in a facile and scalable way.
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Affiliation(s)
- Ronglei Fan
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
| | - Jie Mao
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
| | - Zhihao Yin
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
| | - Jiansheng Jie
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
| | - Wen Dong
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
| | - Liang Fang
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
| | - Fengang Zheng
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
| | - Mingrong Shen
- Department of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films and ‡Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215006, China
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13
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Shih HY, Lee WH, Kao WC, Chuang YC, Lin RM, Lin HC, Shiojiri M, Chen MJ. Low-temperature atomic layer epitaxy of AlN ultrathin films by layer-by-layer, in-situ atomic layer annealing. Sci Rep 2017; 7:39717. [PMID: 28045075 PMCID: PMC5206640 DOI: 10.1038/srep39717] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/25/2016] [Indexed: 11/18/2022] Open
Abstract
Low-temperature epitaxial growth of AlN ultrathin films was realized by atomic layer deposition (ALD) together with the layer-by-layer, in-situ atomic layer annealing (ALA), instead of a high growth temperature which is needed in conventional epitaxial growth techniques. By applying the ALA with the Ar plasma treatment in each ALD cycle, the AlN thin film was converted dramatically from the amorphous phase to a single-crystalline epitaxial layer, at a low deposition temperature of 300 °C. The energy transferred from plasma not only provides the crystallization energy but also enhances the migration of adatoms and the removal of ligands, which significantly improve the crystallinity of the epitaxial layer. The X-ray diffraction reveals that the full width at half-maximum of the AlN (0002) rocking curve is only 144 arcsec in the AlN ultrathin epilayer with a thickness of only a few tens of nm. The high-resolution transmission electron microscopy also indicates the high-quality single-crystal hexagonal phase of the AlN epitaxial layer on the sapphire substrate. The result opens a window for further extension of the ALD applications from amorphous thin films to the high-quality low-temperature atomic layer epitaxy, which can be exploited in a variety of fields and applications in the near future.
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Affiliation(s)
- Huan-Yu Shih
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan, R.O.C
| | - Wei-Hao Lee
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan, R.O.C
| | - Wei-Chung Kao
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan, R.O.C
| | - Yung-Chuan Chuang
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan, R.O.C
| | - Ray-Ming Lin
- Department of Electronic Engineering, Chang Gung University, Tao-Yuan 333, Taiwan, R.O.C.,Department of Radiation Oncology, Chang Gung Memorial Hospital, Tao-Yuan 333, Taiwan, R.O.C
| | - Hsin-Chih Lin
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan, R.O.C
| | | | - Miin-Jang Chen
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan, R.O.C
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14
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Wang LX, Zhou ZQ, Hao HC, Lu M. A porous Si-emitter crystalline-Si solar cell with 18.97% efficiency. NANOTECHNOLOGY 2016; 27:425207. [PMID: 27640447 DOI: 10.1088/0957-4484/27/42/425207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A p-n junction was made on p-type Si〈100〉 wafer (15 × 15 × 0.2 mm(3) in size) via phosphorous diffusion at 900 °C. Porous Si (PSi) with ultralow reflectivity (<0.3% in the ultraviolet and visible regimes) was achieved by etching a Ag-coated n(+) Si emitter in a solution of HF, H2O2 and H2O. The PSi was found to mainly consist of Si nanocrystallites with bandgap widths larger than that of bulk Si. Compared to other micro- or nanostructured Si-based crystalline-Si solar cells found in the literature, this PSi one possessed the feature of a graded band gap, which helped to suppress the surface recombination. In addition, the preparation method was readily applicable on large-scale-sized Si wafers. Also, the PSi acted as a down-shifter that absorbed the ultraviolet/violet light to which the Si solar cell responded poorly, and emitted a red one to which the cell responded well. Front and rear surface passivations were conducted by using SiO2 and Al2O3, respectively, to suppress the surface recombination and to facilitate the charge transfer. Indium-tin-oxide was used as the front electrode that was in good contact with the PSi, and Al was used as the rear one. For such a PSi-emitter crystalline-Si solar cell, enhancements of the photovoltaic responses from the ultraviolet to near-infrared regimes were observed; the open-circuit voltage was 606.8 mV, the short-circuit current density was 40.13 mA cm(-2), the fill factor was 0.779 and the conversion efficiency was 18.97%.
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Affiliation(s)
- Liang-Xing Wang
- Department of Optical Science and Engineering, and Shanghai Ultra-Precision Optical Manufacturing Engineering Center, Fudan University, Shanghai 200433, People's Republic of China
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Zeng M, Peng X, Liao J, Wang G, Li Y, Li J, Qin Y, Wilson J, Song A, Lin S. Enhanced photoelectrochemical performance of quantum dot-sensitized TiO2 nanotube arrays with Al2O3 overcoating by atomic layer deposition. Phys Chem Chem Phys 2016; 18:17404-13. [DOI: 10.1039/c6cp01299j] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conformal Al2O3 overcoating by ALD can drastically enhance the PEC performance of quantum dot-sensitized TiO2 nanotube arrays.
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Simon DK, Jordan PM, Mikolajick T, Dirnstorfer I. On the Control of the Fixed Charge Densities in Al2O3-Based Silicon Surface Passivation Schemes. ACS APPLIED MATERIALS & INTERFACES 2015; 7:28215-22. [PMID: 26618751 DOI: 10.1021/acsami.5b06606] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A controlled field-effect passivation by a well-defined density of fixed charges is crucial for modern solar cell surface passivation schemes. Al2O3 nanolayers grown by atomic layer deposition contain negative fixed charges. Electrical measurements on slant-etched layers reveal that these charges are located within a 1 nm distance to the interface with the Si substrate. When inserting additional interface layers, the fixed charge density can be continuously adjusted from 3.5 × 10(12) cm(-2) (negative polarity) to 0.0 and up to 4.0 × 10(12) cm(-2) (positive polarity). A HfO2 interface layer of one or more monolayers reduces the negative fixed charges in Al2O3 to zero. The role of HfO2 is described as an inert spacer controlling the distance between Al2O3 and the Si substrate. It is suggested that this spacer alters the nonstoichiometric initial Al2O3 growth regime, which is responsible for the charge formation. On the basis of this charge-free HfO2/Al2O3 stack, negative or positive fixed charges can be formed by introducing additional thin Al2O3 or SiO2 layers between the Si substrate and this HfO2/Al2O3 capping layer. All stacks provide very good passivation of the silicon surface. The measured effective carrier lifetimes are between 1 and 30 ms. This charge control in Al2O3 nanolayers allows the construction of zero-fixed-charge passivation layers as well as layers with tailored fixed charge densities for future solar cell concepts and other field-effect based devices.
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Affiliation(s)
- Daniel K Simon
- NaMLab gGmbH , Nöthnitzer Strasse 64, D-01187 Dresden, Germany
| | - Paul M Jordan
- NaMLab gGmbH , Nöthnitzer Strasse 64, D-01187 Dresden, Germany
| | - Thomas Mikolajick
- NaMLab gGmbH , Nöthnitzer Strasse 64, D-01187 Dresden, Germany
- Chair of Nanoelectronic Materials, TU Dresden , D-01062 Dresden, Germany
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Wang H, Zhang C, Rana F. Surface Recombination Limited Lifetimes of Photoexcited Carriers in Few-Layer Transition Metal Dichalcogenide MoS₂. NANO LETTERS 2015; 15:8204-10. [PMID: 26535607 DOI: 10.1021/acs.nanolett.5b03708] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We present results on photoexcited carrier lifetimes in few-layer transition metal dichalcogenide MoS2 using nondegenerate ultrafast optical pump-probe technique. Our results show a sharp increase of the carrier lifetimes with the number of layers in the sample. Carrier lifetimes increase from few tens of picoseconds in monolayer samples to more than a nanosecond in 10-layer samples. The inverse carrier lifetime was found to scale according to the probability of the carriers being present at the surface layers, as given by the carrier wave function in few layer samples, which can be treated as quantum wells. The carrier lifetimes were found to be largely independent of the temperature, and the inverse carrier lifetimes scaled linearly with the photoexcited carrier density. These observations are consistent with defect-assisted carrier recombination, in which the capture of electrons and holes by defects occurs via Auger scatterings. Our results suggest that carrier lifetimes in few-layer samples are surface recombination limited due to the much larger defect densities at surface layers compared with the inner layers.
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Affiliation(s)
- Haining Wang
- School of Electrical and Computer Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Changjian Zhang
- School of Electrical and Computer Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Farhan Rana
- School of Electrical and Computer Engineering, Cornell University , Ithaca, New York 14853, United States
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Chen HY, Lu HL, Ren QH, Zhang Y, Yang XF, Ding SJ, Zhang DW. Enhanced photovoltaic performance of inverted pyramid-based nanostructured black-silicon solar cells passivated by an atomic-layer-deposited Al2O3 layer. NANOSCALE 2015; 7:15142-15148. [PMID: 26243694 DOI: 10.1039/c5nr03353e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Inverted pyramid-based nanostructured black-silicon (BS) solar cells with an Al2O3 passivation layer grown by atomic layer deposition (ALD) have been demonstrated. A multi-scale textured BS surface combining silicon nanowires (SiNWs) and inverted pyramids was obtained for the first time by lithography and metal catalyzed wet etching. The reflectance of the as-prepared BS surface was about 2% lower than that of the more commonly reported upright pyramid-based SiNW BS surface over the whole of the visible light spectrum, which led to a 1.7 mA cm(-2) increase in short circuit current density. Moreover, the as-prepared solar cells were further passivated by an ALD-Al2O3 layer. The effect of annealing temperature on the photovoltaic performance of the solar cells was investigated. It was found that the values of all solar cell parameters including short circuit current, open circuit voltage, and fill factor exhibit a further increase under an optimized annealing temperature. Minority carrier lifetime measurements indicate that the enhanced cell performance is due to the improved passivation quality of the Al2O3 layer after thermal annealing treatments. By combining these two refinements, the optimized SiNW BS solar cells achieved a maximum conversion efficiency enhancement of 7.6% compared to the cells with an upright pyramid-based SiNWs surface and conventional SiNx passivation.
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Affiliation(s)
- Hong-Yan Chen
- State Key Laboratory of ASIC and System, Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, Shanghai 200433, People's Republic of China.
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Wei H, Shi J, Xu X, Xiao J, Luo J, Dong J, Lv S, Zhu L, Wu H, Li D, Luo Y, Meng Q, Chen Q. Enhanced charge collection with ultrathin AlOx electron blocking layer for hole-transporting material-free perovskite solar cell. Phys Chem Chem Phys 2015; 17:4937-44. [PMID: 25594083 DOI: 10.1039/c4cp04902k] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An ultrathin AlOx layer has been deposited onto a CH3NH3PbI3 film using atomic layer deposition technology, to construct a metal-insulator-semiconductor (MIS) back contact for the hole-transporting material-free perovskite solar cell. By optimization of the ALD deposition cycles, the average power conversion efficiency (PCE) of the cell has been enhanced from 8.61% to 10.07% with a highest PCE of 11.10%. It is revealed that the improvement in cell performance with this MIS back contact is mainly attributed to the enhancement in charge collection resulting from the electron blocking effect of the AlOx layer.
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Affiliation(s)
- Huiyun Wei
- Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China.
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Wang WC, Tsai MC, Yang J, Hsu C, Chen MJ. Efficiency Enhancement of Nanotextured Black Silicon Solar Cells Using Al2O3/TiO2 Dual-Layer Passivation Stack Prepared by Atomic Layer Deposition. ACS APPLIED MATERIALS & INTERFACES 2015; 7:10228-10237. [PMID: 25919200 DOI: 10.1021/acsami.5b00677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this study, efficient nanotextured black silicon (NBSi) solar cells composed of silicon nanowire arrays and an Al2O3/TiO2 dual-layer passivation stack on the n(+) emitter were fabricated. The highly conformal Al2O3 and TiO2 surface passivation layers were deposited on the high-aspect-ratio surface of the NBSi wafers using atomic layer deposition. Instead of the single Al2O3 passivation layer with a negative oxide charge density, the Al2O3/TiO2 dual-layer passivation stack treated with forming gas annealing provides a high positive oxide charge density and a low interfacial state density, which are essential for the effective field-effect and chemical passivation of the n(+) emitter. In addition, the Al2O3/TiO2 dual-layer passivation stack suppresses the total reflectance over a broad range of wavelengths (400-1000 nm). Therefore, with the Al2O3/TiO2 dual-layer passivation stack, the short-circuit current density and efficiency of the NBSi solar cell were increased by 11% and 20%, respectively. In conclusion, a high efficiency of 18.5% was achieved with the NBSi solar cells by using the n(+)-emitter/p-base structure passivated with the Al2O3/TiO2 stack.
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Affiliation(s)
- Wei-Cheng Wang
- †Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Meng-Chen Tsai
- †Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Jason Yang
- ‡Sino-American Silicon Products Inc., Yilan Branch, Yilan County 26841, Taiwan
| | - Chuck Hsu
- §Sino-American Silicon Products Inc., Hsinchu Science Park 30075, Taiwan
| | - Miin-Jang Chen
- †Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
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Lin XX, Zeng Y, Zhong SH, Huang ZG, Qian HQ, Ling J, Zhu JB, Shen WZ. Realization of improved efficiency on nanostructured multicrystalline silicon solar cells for mass production. NANOTECHNOLOGY 2015; 26:125401. [PMID: 25736199 DOI: 10.1088/0957-4484/26/12/125401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the realization of both excellent optical and electrical properties of nanostructured multicrystalline silicon solar cells by a simple and industrially compatible technique of surface morphology modification. The nanostructures are prepared by Ag-catalyzed chemical etching and subsequent NaOH treatment with controllable geometrical parameters and surface area enhancement ratio. We have examined in detail the influence of different surface area enhancement ratios on reflectance, carrier recombination characteristics and cell performance. By conducting a quantitative analysis of these factors, we have successfully demonstrated a higher-than-traditional output performance of nanostructured multicrystalline silicon solar cells with a low average reflectance of 4.93%, a low effective surface recombination velocity of 6.59 m s(-1), and a certified conversion efficiency of 17.75% on large size (156 × 156 mm(2)) silicon cells, which is ∼0.3% higher than the acid textured counterparts. The present work opens a potential prospect for the mass production of nanostructured solar cells with improved efficiencies.
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Affiliation(s)
- X X Lin
- Institute of Solar Energy, Laboratory of Condensed Matter Spectroscopy and Opto-Electronic Physics, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China. Department of Mathematics and Physics, Shanghai Dian Ji University, Shanghai 201306, People's Republic of China
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Niu W, Li X, Karuturi SK, Fam DW, Fan H, Shrestha S, Wong LH, Tok AIY. Applications of atomic layer deposition in solar cells. NANOTECHNOLOGY 2015; 26:064001. [PMID: 25604730 DOI: 10.1088/0957-4484/26/6/064001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Atomic layer deposition (ALD) provides a unique tool for the growth of thin films with excellent conformity and thickness control down to atomic levels. The application of ALD in energy research has received increasing attention in recent years. In this review, the versatility of ALD in solar cells will be discussed. This is specifically focused on the fabrication of nanostructured photoelectrodes, surface passivation, surface sensitization, and band-structure engineering of solar cell materials. Challenges and future directions of ALD in the applications of solar cells are also discussed.
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Affiliation(s)
- Wenbin Niu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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Zhong S, Huang Z, Lin X, Zeng Y, Ma Y, Shen W. High-efficiency nanostructured silicon solar cells on a large scale realized through the suppression of recombination channels. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:555-561. [PMID: 25205286 DOI: 10.1002/adma.201401553] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Revised: 06/17/2014] [Indexed: 06/03/2023]
Abstract
Nanostructured silicon solar cells show great potential for new-generation photovoltaics due to their ability to approach ideal light-trapping. However, the nanofeatured morphology that brings about the optical benefits also introduces new recombination channels, and severe deterioration in the electrical performance even outweighs the gain in optics in most attempts. This Research News article aims to review the recent progress in the suppression of carrier recombination in silicon nanostructures, with the emphasis on the optimization of surface morphology and controllable nanostructure height and emitter doping concentration, as well as application of dielectric passivation coatings, providing design rules to realize high-efficiency nanostructured silicon solar cells on a large scale.
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Affiliation(s)
- Sihua Zhong
- Institute of Solar Energy, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai, 200240, PR China
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Song JW, Nam YH, Park MJ, Shin SM, Wehrspohn RB, Lee JH. Hydroxyl functionalization improves the surface passivation of nanostructured silicon solar cells degraded by epitaxial regrowth. RSC Adv 2015. [DOI: 10.1039/c5ra03775a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nanoscale epitaxy of silicon is found to deteriorate the passivation performance by ALD-Al2O3in nanostructured solar cells. Hydroxyl functionalization by oxygen plasma decreased the surface recombination velocity.
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Affiliation(s)
- Jae-Won Song
- Department of Materials and Chemical Engineering
- Hanyang University
- Ansan
- Korea
| | - Yoon-Ho Nam
- Department of Materials and Chemical Engineering
- Hanyang University
- Ansan
- Korea
| | - Min-Joon Park
- Department of Materials and Chemical Engineering
- Hanyang University
- Ansan
- Korea
| | - Sun-Mi Shin
- Department of Materials and Chemical Engineering
- Hanyang University
- Ansan
- Korea
| | - Ralf B. Wehrspohn
- Institute of Physics
- Martin-Luther-Universität Halle-Wittenberg
- Fraunhofer Institute for Mechanics of Materials IWM
- Halle 06120
- Germany
| | - Jung-Ho Lee
- Department of Materials and Chemical Engineering
- Hanyang University
- Ansan
- Korea
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Kim Y, Lee S, Lee K, Shim S, Kim JY, Lee HW, Choi D. Self-assembled plasmonic nanoparticles on vertically aligned carbon nanotube electrodes via thermal evaporation. ACS APPLIED MATERIALS & INTERFACES 2014; 6:20423-20429. [PMID: 25384110 DOI: 10.1021/am505999e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This study details the development of a large-area, three-dimensional (3D), plasmonic integrated electrode (PIE) system. Vertically aligned multiwalled carbon nanotube (VA-MWNT) electrodes are grown and populated with self-assembling silver nanoparticles via thermal evaporation. Due to the geometric and surface characteristics of VA-MWNTs, evaporated silver atoms form nanoparticles approximately 15-20 nm in diameter. The nanoparticles are well distributed on VA-MWNTs, with a 5-10 nm gap between particles. The size and gap of the self-assembled plasmonic nanoparticles is dependent upon both the length of the MWNT and the thickness of the evaporated silver. The wetting properties of water of the VA-MWNT electrodes change from hydrophilic (∼70°) to hydrophobic (∼120°) as a result of the evaporated silver. This effect is particularly pronounced on the VA-MWNT electrodes with a length of 1 μm, where the contact angle is altered from an initial 8° to 124°. Based on UV-visible spectroscopic analysis, plasmonic resonance of the PIE systems occurs at a wavelength of approximately 400 nm. The optical behavior was found to vary as a function of MWNT length, with the exception of MWNT with a length of 1 μm. Using our PIE systems, we were able to obtain clear surface-enhanced Raman scattering (SERS) spectra with a detection limit of ∼10 nM and an enhancement factor of ∼10(6). This PIE system shows promise for use as a novel electrode system in next-generation optoelectronics such as photovoltaics, light-emitting diodes, and solar water splitting.
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Affiliation(s)
- Youngmin Kim
- Department of Mechanical Engineering, College of Engineering, Kyung Hee University , Yongin, 446-701, Republic of Korea
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Ziegler J, Haschke J, Käsebier T, Korte L, Sprafke AN, Wehrspohn RB. Influence of black silicon surfaces on the performance of back-contacted back silicon heterojunction solar cells. OPTICS EXPRESS 2014; 22 Suppl 6:A1469-A1476. [PMID: 25607304 DOI: 10.1364/oe.22.0a1469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The influence of different black silicon (b-Si) front side textures prepared by inductively coupled reactive ion etching (ICP-RIE) on the performance of back-contacted back silicon heterojunction (BCB-SHJ) solar cells is investigated in detail regarding their optical performance, black silicon surface passivation and internal quantum efficiency. Under optimized conditions the effective minority carrier lifetime measured on black silicon surfaces passivated with Al(2)O(3) can be higher than lifetimes measured for the SiO(2)/SiN(x) passivation stack used in the reference cells with standard KOH textures. However, to outperform the electrical current of silicon back-contact cells, the black silicon back-contact cell process needs to be optimized with aspect to chemical and thermal stability of the used dielectric layer combination on the cell.
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Wang F, Zhang X, Wang L, Jiang Y, Wei C, Sun J, Zhao Y. Role of hydrogen plasma pretreatment in improving passivation of the silicon surface for solar cells applications. ACS APPLIED MATERIALS & INTERFACES 2014; 6:15098-15104. [PMID: 25141300 DOI: 10.1021/am5031837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have investigated the role of hydrogen plasma pretreatment in promoting silicon surface passivation, in particular examining its effects on modifying the microstructure of the subsequently deposited thin hydrogenated amorphous silicon (a-Si:H) passivation film. We demonstrate that pretreating the silicon surface with hydrogen plasma for 40 s improves the homogeneity and compactness of the a-Si:H film by enhancing precursor diffusion and thus increasing the minority carrier lifetime (τ(eff)). However, excessive pretreatment also increases the density of dangling bond defects on the surface due to etching effects of the hydrogen plasma. By varying the duration of hydrogen plasma pretreatment in fabricating silicon heterojunction solar cells based on textured substrates, we also demonstrate that, although the performance of the solar cells shows a similar tendency to that of the τ(eff) on polished wafers, the optimal duration is prolonged owing to the differences in the surface morphology of the substrates. These results suggest that the hydrogen plasma condition must be carefully regulated to achieve the optimal level of surface atomic hydrogen coverage and avoid the generation of defects on the silicon wafer.
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Affiliation(s)
- Fengyou Wang
- Institute of Photo-electronics Thin Film Devices and Technique of Nankai University , Key Laboratory of Photo-electronics Thin Film Devices and Technique of Tianjin, Key Laboratory of Photo-Electronic Information Science and Technology of Ministry of Education (Nankai University), Tianjin 300071, China
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Wang F, Zhang X, Wang L, Jiang Y, Wei C, Xu S, Zhao Y. Improved amorphous/crystalline silicon interface passivation for heterojunction solar cells by low-temperature chemical vapor deposition and post-annealing treatment. Phys Chem Chem Phys 2014; 16:20202-8. [DOI: 10.1039/c4cp02212b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Xu Z, Yao Y, Brueckner EP, Li L, Jiang J, Nuzzo RG, Liu GL. Black silicon solar thin-film microcells integrating top nanocone structures for broadband and omnidirectional light-trapping. NANOTECHNOLOGY 2014; 25:305301. [PMID: 25006119 DOI: 10.1088/0957-4484/25/30/305301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Recently developed classes of monocrystalline silicon solar microcells (μ-cell) can be assembled into modules with characteristics (i.e., mechanically flexible forms, compact concentrator designs, and high-voltage outputs) that would be impossible to achieve using conventional, wafer-based approaches. In this paper, we describe a highly dense, uniform and non-periodic nanocone forest structure of black silicon (bSi) created on optically-thin (30 μm) μ-cells for broadband and omnidirectional light-trapping with a lithography-free and high-throughput plasma texturizing process. With optimized plasma etching conditions and a silicon nitride passivation layer, black silicon μ-cells, when embedded in a polymer waveguiding layer, display dramatic increases of as much as 65.7% in short circuit current, as compared to a bare silicon device. The conversion efficiency increases from 8.1% to 11.5% with a small drop in open circuit voltage and fill factor.
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Affiliation(s)
- Zhida Xu
- Micro and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, IL 61801, USA
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Xiu F, Lin H, Fang M, Dong G, Yip S, Ho JC. Fabrication and enhanced light-trapping properties of three-dimensional silicon nanostructures for photovoltaic applications. PURE APPL CHEM 2014. [DOI: 10.1515/pac-2013-1119] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIn order to make photovoltaics an economically viable energy solution, next-generation solar cells with higher energy conversion efficiencies and lower costs are urgently desired. Among many possible solutions, three-dimensional (3D) silicon nanostructures with excellent light-trapping properties are one of the promising candidates and have recently attracted considerable attention for cost-effective photovoltaic applications. This is because their enhanced light-trapping characteristics and high carrier collection efficiencies can enable the use of cheaper and thinner silicon materials. In this review, recent developments in the controllable fabrication of 3D silicon nanostructures are summarized, followed by the investigation of optical properties on a number of different nanostructures, including nanowires, nanopillars, nanocones, nanopencils, and nanopyramids, etc. Even though nanostructures with radial p-n junction demonstrate excellent photon management properties and enhanced photo-carrier collection efficiencies, the photovoltaic performance of nanostructure-based solar cells is still significantly limited due to the high surface recombination effect, which is induced by high-density surface defects as well as the large surface area in high-aspect-ratio nanostructures. In this regard, various approaches in reducing the surface recombination are discussed and an overall geometrical consideration of both light-trapping and recombination effects to yield the best photovoltaic properties are emphasized.
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Affiliation(s)
| | - Hao Lin
- 1Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Ming Fang
- 1Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Guofa Dong
- 1Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, China
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Ko CT, Han YY, Wang WC, Shieh J, Chen MJ. Enhancement of light emission from silicon by precisely tuning coupled localized surface plasmon resonance of a nanostructured platinum layer prepared by atomic layer deposition. ACS APPLIED MATERIALS & INTERFACES 2014; 6:4179-4185. [PMID: 24564803 DOI: 10.1021/am405853d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Plasmonic enhancement of photoluminescence from bulk silicon was achieved by spectrally tailoring coupled localized surface plasmon resonance (LSPR) in the Al2O3 cover/nanostructured platinum (nano-Pt)/Al2O3 spacer/silicon multilayer structures prepared by atomic layer deposition (ALD). Agreement between the simulation and experimental data indicates that the plasmonic activity originates from absorption enhancement due to coupled LSPR. Because of the optimized dielectric environment deposited by ALD around the nano-Pt layer, absorption of the multilayer structure was enhanced by the precise tuning of coupled LSPR to coincide with the excitation wavelength. This accurate plasmonic multilayer structure grown by ALD with high precision, tunability, uniformity, and reproducibility can be further applied in efficient light-emitting devices.
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Affiliation(s)
- Chung-Ting Ko
- Department of Materials Science and Engineering, National Taiwan University , No. 1, Section 4, Roosevelt Road, Taipei 10617 Taiwan
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Sharma M, Pudasaini PR, Ruiz-Zepeda F, Elam D, Ayon AA. Ultrathin, flexible organic-inorganic hybrid solar cells based on silicon nanowires and PEDOT:PSS. ACS APPLIED MATERIALS & INTERFACES 2014; 6:4356-63. [PMID: 24568116 DOI: 10.1021/am500063w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Recently, free-standing, ultrathin, single-crystal silicon (c-Si) membranes have attracted considerable attention as a suitable material for low-cost, mechanically flexible electronics. In this paper, we report a promising ultrathin, flexible, hybrid solar cell based on silicon nanowire (SiNW) arrays and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The free-standing, ultrathin c-Si membranes of different thicknesses were produced by KOH etching of double-side-polished silicon wafers for various etching times. The processed free-standing silicon membranes were observed to be mechanically flexible, and in spite of their relatively small thickness, the samples tolerated the different steps of solar cell fabrication, including surface nanotexturization, spin-casting, dielectric film deposition, and metallization. However, in terms of the optical performance, ultrathin c-Si membranes suffer from noticeable transmission losses, especially in the long-wavelength region. We describe the experimental performance of a promising light-trapping scheme in the aforementioned ultrathin c-Si membranes of thicknesses as small as 5.7 μm employing front-surface random SiNW texturization in combination with a back-surface distribution of silver (Ag) nanoparticles (NPs). We report the enhancement of both the short-circuit current density (JSC) and the open-circuit voltage (VOC) that has been achieved in the described devices. Such enhancement is attributable to the plasmonic backscattering effect of the back-surface Ag NPs, which led to an overall 10% increase in the power conversion efficiency (PCE) of the devices compared to similar structures without Ag NPs. A PCE in excess of 6.62% has been achieved in the described devices having a c-Si membrane of thickness 8.6 μm. The described device technology could prove crucial in achieving an efficient, low-cost, mechanically flexible photovoltaic device in the near future.
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Affiliation(s)
- Manisha Sharma
- Department of Chemistry and ‡Department of Physics and Astronomy, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249, United States
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