Modeling of Optical Properties of Black Silicon/Crystalline Silicon

Ravindra, Nuggehalli M.; Marthi, Sita Rajyalaxmi; Sekhri, Suramya

doi:10.21767/2472-1948.100001

Cited by 6 publications

(4 citation statements)

References 50 publications

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“…A simple cascaded-matrix model was used to calculate the optical reflectivity of the wafer in the visible and near-infrared range. The pyramid structure on a semi-infinite Si substrate was modeled using the effective medium approximation, 46 considering that the dimensions of the nanostructure are smaller than the wavelength of interest. The corresponding calculated curves are presented in Figure 14 b, where significant reduction in reflectivity is observed when the Si multilayer includes a layer whose effective index represents 200 nm-high pyramids, qualitatively reproducing the experimental results.…”

Section: Discussionmentioning

confidence: 99%

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

et al. 2022

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The process of deep texturization of the crystalline silicon surface is intimately related to its promising diverse applications, such as bactericidal surfaces for integrated lab-on-chip devices and absorptive optical layers (black silicon—BSi). Surface structuring by a maskless texturization appeals as a cost-effective approach, which is up-scalable for large-area production. In the case of silicon, it occurs by means of reactive plasma processes (RIE—reactive-ion etching) using fluorocarbon CF 4 and H 2 as reaction gases, leading to self-assembled cylindrical and pyramidal nanopillars. The mechanism of silicon erosion has been widely studied and described as it is for the masked RIE process. However, the onset of the erosion and the reaction kinetics leading to defined maskless patterning have not been unraveled to date. In this work, we specifically tackle this issue by analyzing the results of three different RIE recipes, specifically designed for the purpose. The mechanism of surface self-nanopatterning is revealed by deeply investigating the physical chemistry of the etching process at the nanoscale and the evolution of surface morphology. We monitored the progress in surface patterning and the composition of the etching plasma at different times during the RIE process. We confirm that nanopattering issues from a net erosion, as contributed by chemical etching, physical sputtering, and by the synergistic plasma effect. We propose a qualitative model to explain the onset, the evolution, and the stopping of the process. As the RIE process is started, a high density of surface defects is initially created at the free silicon surface by energetic ion sputtering. Contextually, a polymeric overlayer is synthesized on the Si surface, as thick as 5 nm on average, and self-aggregates into nanoclusters. The latter phenomenon can be explained by considering that the initial creation of surface defects increases the activation energy for surface diffusion of deposited CF and CF 2 species and prevents them from aggregating into a continuous Volmer–Weber polymeric film. The clusterization of the polymer provides the self-masking effect since the beginning, which eventually triggers surface patterning. Once started, the maskless texturing proceeds in analogy with the masked case, that is, by combined chemical etching and ion sputtering, and ceases because of the loss of ion energy. In the case of CF 4 /H 2 RIE processes at 10% of H 2 and by supplying 200 W of RF power for 20 min, nanopillars of 200 nm in height and 100 nm in width were formed. We therefore propose that a precise assessment of surface defect formation and density in dependence on the initial RIE process parameters can be the key to open a full control of outcomes of maskless patterning.

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Section: Discussionmentioning

confidence: 99%

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

et al. 2022

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“…However, in the literature, there is a lack of a theoretical model that describes the conversion of energies in a b-Si photovoltaic cell. Most studies have focused on only the optical aspects of a b-Si surface, with few, if any, focusing on the coupled opto-electro-thermal modelling of a b-Si photovoltaic cell [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. In several studies, the electrical modelling of the b-Si photovoltaic cells has been brief and often assumed an ideal light-to-electrical-energy conversion, disregarding the effects of recombination and other losses [4,5,10,16].…”

Section: Introductionmentioning

confidence: 99%

An Opto-Electro-Thermal Model for Black-Silicon Assisted Photovoltaic Cells in Thermophotovoltaic Applications

2023

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Black silicon (b-Si)-assisted photovoltaic cells have textured b-Si surfaces, which have excellent light-trapping properties. There has been a limited amount of work performed on the theoretical modelling of b-Si photovoltaic cells, and hence, in this work, a coupled optical-electrical-thermal model has been proposed for the simulation of b-Si photovoltaic cells. In particular, the thermal aspects in b-Si photovoltaic cells have not been discussed in the literature. In the proposed model, the finite-difference time-domain (FDTD) method was used to study the optical response of the b-Si photovoltaic cell. Semiconductor equations were used for the electrical modelling of the cell. For the thermal model, the Energy Balance Transport Model was used. The developed model was used to simulate b-Si photovoltaic cells under thermophotovoltaic sources. The impacts of heat generation on the electrical performance of thermophotovoltaic cells are discussed. Simulation results from this study showed that black silicon layer improved efficiency and power output in thermophotovoltaic cells compared to thermophotovoltaic cells with no surface texture. In addition, heat generation due to Joule heating and electron thermalization in b-Si-assisted thermophotovoltaic cells reduced the open-circuit voltage and electrical performance.

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“…Recently porous silicon (Si) nanostructures as nanowires (NWs) are intensively studied in view of their possible applications in optoelectronics, photonics, and sensorics [1][2][3][4][5]. Si NWs possess unique electrical and optical properties, which are prospective for biomedicine [6][7][8] and advanced energy and environment applications [9].…”

Section: Introductionmentioning

confidence: 99%

Nonlinear analysis of the degree of order and chaos of morphology of porous silicon nanostructures

Zhanabaev

Grevtseva

Gonchar

et al. 2019

Proceedings of the v International Conference Information Technology and Nanotechnology 2019

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This work has been done to identify quantitative criteria the degree of order and chaos morphology of porous layers consisting of silicon nanowire arrays. In order to fulfill the work, a method of using metal-assisted chemical etching has been utilized to produce nanowires. There has been done a work of digital processing of porous film images which were extracted by scanning electron microscope. Informational-entropic and Fourier analysis have been applied to quantitatively describe the degree of order and chaos in nanostructure distribution in the layers. Self-similarity of the layer morphology has been quantitatively described via its fractal dimensions by correlation method. The applied approach for image processing allows us to distinguish the morphological features of as-called "black" (more ordered) and "white" (less ordered) silicon layers, which are characterized by minimal and maximal optical reflection, respectively. From all of the methods of digital techniques that we have used the method for determining the conditional information of a chaotic set was proved to be the most informative.

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Modeling of Optical Properties of Black Silicon/Crystalline Silicon

Cited by 6 publications

References 50 publications

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

An Opto-Electro-Thermal Model for Black-Silicon Assisted Photovoltaic Cells in Thermophotovoltaic Applications

Nonlinear analysis of the degree of order and chaos of morphology of porous silicon nanostructures

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Modeling of Optical Properties of Black Silicon/Crystalline Silicon

Cited by 6 publications

References 50 publications

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF4/H2 Plasma Reactive-Ion Etching

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF4/H2 Plasma Reactive-Ion Etching

An Opto-Electro-Thermal Model for Black-Silicon Assisted Photovoltaic Cells in Thermophotovoltaic Applications

Nonlinear analysis of the degree of order and chaos of morphology of porous silicon nanostructures

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Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching

Unraveling the Mechanism of Maskless Nanopatterning of Black Silicon by CF₄/H₂ Plasma Reactive-Ion Etching