Enhanced selective solar absorption of surface nanotextured semi-insulating 6H–SiC

Mastellone, Matteo; Bellucci, A.; Girolami, M.; Montereali, Rosa Maria; Orlando, S.; Polini, Riccardo; Serpente, Valerio; Sani, Elisa; Valentini, Veronica; Vincenti, M. A.

doi:10.1016/j.optmat.2020.109967

Cited by 26 publications

(12 citation statements)

References 35 publications

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“…LIPSS allows indeed for an accurate control of the physical and/or chemical properties of the laser-treated materials. In particular, in the case of wide-bandgap semiconductors (e.g., diamond [ 1 , 2 , 3 , 4 , 5 , 6 ] and SiC [ 21 , 22 ]), surface fs-laser treatments, leading to the formation of LIPSS, strongly influence the optical properties, increasing solar absorptance, in two different ways. First, LIPSS acts as a diffraction grating for the impinging photons, thus enhancing light trapping [ 23 ]; in this sense, it is crucial to ensure regular, well-defined structures uniformly distributed over the largest possible area of the treated material, aimed at minimizing the escape probability of coupled light.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

et al. 2020

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Irradiation of diamond with femtosecond (fs) laser pulses in ultra-high vacuum (UHV) conditions results in the formation of surface periodic nanostructures able to strongly interact with visible and infrared light. As a result, native transparent diamond turns into a completely different material, namely “black” diamond, with outstanding absorptance properties in the solar radiation wavelength range, which can be efficiently exploited in innovative solar energy converters. Of course, even if extremely effective, the use of UHV strongly complicates the fabrication process. In this work, in order to pave the way to an easier and more cost-effective manufacturing workflow of black diamond, we demonstrate that it is possible to ensure the same optical properties as those of UHV-fabricated films by performing an fs-laser nanostructuring at ambient conditions (i.e., room temperature and atmospheric pressure) under a constant He flow, as inferred from the combined use of scanning electron microscopy, Raman spectroscopy, and spectrophotometry analysis. Conversely, if the laser treatment is performed under a compressed air flow, or a N2 flow, the optical properties of black diamond films are not comparable to those of their UHV-fabricated counterparts.

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Section: Introductionmentioning

confidence: 99%

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

et al. 2020

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“…Based on the results of the reflectivity and the dielectric function, we can deduce that a femtosecond laser can perform an ultrafast optical change while the Ge thin film is still cold, offering new possibilities for a wide range of Ge applications at both the micro- and nano-scale, in the same way that other semiconductors are utilized currently. For instance, direct femtosecond laser writing applied to Si [ 35 , 36 ], diamond [ 37 , 38 , 39 ], and SiC [ 40 , 41 ] has indeed been shown to significantly increase the photon absorption of the materials in the solar spectrum, allowing for the fabrication of innovative high-performance solar cells [ 42 , 43 , 44 ].…”

Section: Resultsmentioning

confidence: 99%

Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation

et al. 2022

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In this study, we theoretically investigate the response of a germanium thin film under femtosecond pulsed laser irradiation. Electron and lattice temperatures, as well as material-specific optical properties such as dielectric function and reflectivity, were calculated during the irradiation using an extended two-temperature model coupled with the carrier density rate equation and the Drude model. Melting and ablation fluence thresholds were also predicted, resulting in 0.14 J cm−2 and 0.35 J cm−2, respectively. An ultrafast change in both optical and thermal properties was detected upon laser irradiation. Results also indicate that thermal melting occurs after germanium takes on a metallic character during irradiation, and that the impact ionization process may have a critical role in the laser-induced thermal effect. Therefore, we suggest that the origin of the thermal modification of germanium surface under femtosecond laser irradiation is mostly due the impact ionization process and that its effect becomes more important when increasing the laser fluence.

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“…Once the scalability, repeatability and controllability of preparation and processing methods of LIPSS has settled down, the correlation between the specific surface chemistry and topography will be conclusively established in the finished product. These will supply more drawings for applications of WBS and dielectric materials for which surface functionalization is one of the most important features (e.g., catalysts [109], nano and micro-electronics [110], bio-sensing [111], energy conversion [60,112], electrochemical and photoelectrochemical processes [71,113], elementary optical devices such as selective absorbers [80], THz optical components [72,114], etc. ).…”

Section: Discussionmentioning

confidence: 99%

“…In 2020, Mastellone et al, [80] working on semi-insulating 6H-SiC (linearly polarized pulses, λ = 800 nm, τ = 100 fs), further enhanced the optical absorption of the material reporting an increase in the overall solar absorptance, α solar , from 10% up to values of 75%. Furthermore, the spectral selectivity at 1000 K, which is evaluated through the absorptance/emissivity (α/ε) ratio, increased from 0.3 (pristine sample) to approximately 1.7, which is a remarkable achievement when compared with materials specifically developed for solar applications (α/ε > 1.5) [81,82].…”

Section: Institute Of Physicsmentioning

confidence: 99%

LIPSS Applied to Wide Bandgap Semiconductors and Dielectrics: Assessment and Future Perspectives

Mastellone

Pace²,

Curcio

et al. 2022

Materials

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With the aim of presenting the processes governing the Laser-Induced Periodic Surface Structures (LIPSS), its main theoretical models have been reported. More emphasis is given to those suitable for clarifying the experimental structures observed on the surface of wide bandgap semiconductors (WBS) and dielectric materials. The role played by radiation surface electromagnetic waves as well as Surface Plasmon Polaritons in determining both Low and High Spatial Frequency LIPSS is briefly discussed, together with some experimental evidence. Non-conventional techniques for LIPSS formation are concisely introduced to point out the high technical possibility of enhancing the homogeneity of surface structures as well as tuning the electronic properties driven by point defects induced in WBS. Among these, double- or multiple-fs-pulse irradiations are shown to be suitable for providing further insight into the LIPSS process together with fine control on the formed surface structures. Modifications occurring by LIPSS on surfaces of WBS and dielectrics display high potentialities for their cross-cutting technological features and wide applications in which the main surface and electronic properties can be engineered. By these assessments, the employment of such nanostructured materials in innovative devices could be envisaged.

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Enhanced selective solar absorption of surface nanotextured semi-insulating 6H–SiC

Cited by 26 publications

References 35 publications

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation

LIPSS Applied to Wide Bandgap Semiconductors and Dielectrics: Assessment and Future Perspectives

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