Poster De Conférence Année : 2024

Nanostructured Poly-Si and Poly-SiGe Layers for Enhanced Energy Harvesting Applications

Résumé

This work investigates a method to fabricate nanostructured polycrystalline Si (poly- Si) and polycrystalline SiGe (poly-SiGe) layers with high optical absorption and energy harvesting capabilities. As-grown layers are processed on a glass substrate using plasma enhanced chemical vapor deposition (PECVD) with a maximum substrate temperature of 210 . At such a low thermal budget, the deposited layers are in amorphous form with high sheet resistivity values. A post-processing laser annealing treatment of these layers is then used to induce surface nano-structuring and improve their electrical and optical behavior. The laser’s short pulse duration, 24 ns, and wavelength, 248 nm, imply that most of the laser energy density is absorbed by the surface of the a-Si and a-SiGe layers, transforming them to a polycrystalline form upon re-solidification. This guarantees that the underlying substrate remains at a low thermal point throughout the fabrication process. As the substrate remains at a reduced temperature, the intention is that after development of the deposition process and the layer treatment, the resulting nanostructured layers can be implemented on flexible polymer or other temperature sensitive substrates. The optical properties of the fabricated nanostructured layers are analyzed and variations in the laser energy density, number of pulses and treated material are compared. We report absorbance enhancement factors in the range of 20 to 25 for nanostructured poly-Si and as high as 60 for nanostructured poly-SiGe in comparison to the as-grown layers. As SiGe exhibits thermoelectric behavior, further studies in this work involve investigating the thermoelectric performance of the nanostructured poly-SiGe layer. We observe an improvement of 34.4% to the Seebeck coefficient at a temperature nine times lower than that of other processing methods reported in literature, such as nano-structuring using mechanical alloying and thermal annealing approaches. This work presents a waste free, low thermal budget fabrication method of nanostructured poly-Si and poly-SiGe layers. We show that a laser nano-structuring fabrication technique is ideal for applications on temperature sensitive substrates and enables an integration flexibility with other processing methods. Both nanostructured poly-Si and poly-SiGe layers exhibit superior optical absorption that can be fine-tuned depending on the applied laser treatment. An advantage of the nanostructured poly-SiGe layer, in particular, is its improved thermoelectric performance, making it a suitable material for hybrid energy harvesting applications.
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Dates et versions

hal-04905618 , version 1 (22-01-2025)

Identifiants

  • HAL Id : hal-04905618 , version 1

Citer

Joumana El-Rifai, Eliane Bsaibess, Stavros Christopoulos, Fabien Giovannelli, Ahmed Slimani, et al.. Nanostructured Poly-Si and Poly-SiGe Layers for Enhanced Energy Harvesting Applications. EMRS 2024, 2024, Warsaw, Poland. ⟨hal-04905618⟩
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