Optical properties of silicon rich oxides

Summonte, C.; Centurioni, E.; Canino, Mariaconcetta; Allegrezza, M.; Desalvo, A.; Terrasi, A.; Mirabella, S.; Marco, Silvia Di; Stefano, Maria Ausilia Di; Miritello, M.; Savio, R. Lo; Simone, F.; Agosta, Rita

doi:10.1002/pssc.201000413

Cited by 3 publications

(3 citation statements)

References 12 publications

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“…The formation of nanodots in this set of samples was evidenced by TEM diffraction and reported [20]. TEM diffraction also shows that the SiC crystallization occurs in the 3C-SiC polytype.…”

Section: Nanodot Formationsupporting

confidence: 65%

“…After annealing, the SiC-SRC superlattices undergo the following processes: hydrogen evolution after the 600°C annealing step, which is needed to prevent cracking of the films upon high temperature annealing; partial or complete crystallization of the SiC matrix; partial or complete separation and crystallization of the Si component [20]. To follow the structural evolution of the samples upon annealing by means of optical simulation, a database is needed for the n-k functions of the component materials.…”

Section: Simulation Of the Randt Spectramentioning

confidence: 99%

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Optical And Electrical Properties Of Si Nanocrystals Embedded In SiC Matrix

Shukla¹,

Summonte²,

Canino³

et al. 2012

Adv. Mater. Lett.

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Silicon nanocrystals (Si NCs) embedded in a dielectric matrix showing tunable band gap properties have recently emerged as attracting top absorbers in silicon based high efficiency multijunction devices. This paper presents optical and electrical characterization of Si NCs in SiC matrix resulting from annealing at 1100 °C of silicon-rich carbide (SRC)/SiC multilayers produced by Plasma Enhanced Chemical Vapour Deposition (PECVD), varying either the Si content in the SRC or the SiC thickness. Simulation of Reflectance and Transmittance spectra in the UV-Vis revealed that 1) the Si crystallization increases with increasing Si content; 2) a severe shrinkage of the multilayers occurs upon annealing due to the release of hydrogen and to crystallisation; 3) the growth of nanocrystals is affected by atomic environment and diffusivity of involved atoms at the investigated temperature. Temperature dependent conductivity measurements are performed on multlayers and on reference layers. The results show evidence of defect state conduction in the SiC matrix.

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“…The formation of nanodots in this set of samples was evidenced by TEM diffraction and reported [20]. TEM diffraction also shows that the SiC crystallization occurs in the 3C-SiC polytype.…”

Section: Nanodot Formationsupporting

confidence: 65%

Section: Simulation Of the Randt Spectramentioning

confidence: 99%

Optical And Electrical Properties Of Si Nanocrystals Embedded In SiC Matrix

Shukla¹,

Summonte²,

Canino³

et al. 2012

Adv. Mater. Lett.

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“…This explains why, even though solar cells with an open‐circuit voltage ( V oc ) of up to 492 mV have been prepared using Si NCs in SiO 2 , the low short‐circuit current density ( j sc , ≈0.02 mAcm −2 ) and fill factor ( FF , ≈0.25) severely limited the efficiency. Si NCs in SiC (Si NC/SiC) exhibit much better absorption and transport properties and have been used to prepare solar cells with V oc = 282 mV and j sc = 0.34 mAcm −2 . The lower V oc may be related to the poor luminescence quantum yield and carrier lifetime of Si NC/SiC films, but the improved absorption and carrier transport are sufficient to yield much higher j sc , resulting in higher overall efficiency.…”

Section: Introductionmentioning

confidence: 99%

Monolithic Si nanocrystal/crystalline Si tandem cells involving Si nanocrystals in SiC

Schnabel

Canino

Schillinger

et al. 2016

Progress in Photovoltaics

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Monolithic tandem cells involving a top cell with Si nanocrystals embedded in SiC (Si NC/SiC) and a c-Si bottom cell have been prepared. Scanning electron microscopy shows that the intended cell architecture is achieved and that it survives the 1100 °C anneal required to form Si NCs. The cells exhibit mean open-circuit voltages Voc of 900–950 mV, demonstrating tandem cell functionality, with ≤580 mV arising from the c-Si bottom cell and ≥320 mV arising from the Si NC/SiC top cell. The cells are successfully connected using a SiC/Si tunnelling recombination junction that results in very little voltage loss. The short-circuit current densities jsc are, at 0.8–0.9 mAcm−2, rather low and found to be limited by current collection in the top cell. However, equivalent circuit simulations demonstrate that in current-mismatched tandem cells such as the ones studied here, higher jsc, when accompanied by decreased Voc, can arise from shunts or breakdown in the limiting cell rather than improved current collection from the limiting cell. This indicates that Voc is a better optimisation parameter than jsc for tandem cells where the limiting cell exhibits poor junction characteristics. The high-temperature-stable cell architecture developed in this work, coupled with simulations highlighting potential pitfalls in tandem cell analysis, provides a suitable route for optimisation of Si NC layers for photovoltaics on a tandem cell device level

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