Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/11846

TitleHigh-rate deposition of nano-crystalline silicon thin films on plastics
Author(s)Marins, Emílio Sérgio
Guduru, Virendra
Ribeiro, Miguel
Cerqueira, M. F.
Bouattour, Ali
Alpuim, P.
KeywordsNanocrystalline silicon
Thin films
High-rate deposition
Solar cells
Issue date21-Jan-2011
PublisherWiley-VCH Verlag
JournalPhysica Status Solidi C
Citation"Physica Status Solidi C". ISSN 1610-1642. 8:3 (Jan. 2011) 846-849.
Abstract(s)Nanocrystalline silicon (nc-Si:H) is commonly used in the bottom cell of tandem solar cells. With an indirect bandgap, nc-Si:H requires thicker (∼1 µm) films for efficient light harvesting than amorphous Si (a-Si:H) does. Therefore, thin-film high deposition rates are crucial for further cost reduction of highly efficient a–Si:H based photovoltaic technology. Plastic substrates allow for further cost reduction by enabling roll-to-roll inline deposition. In this work, high nc-Si:H deposition rates on plastic were achieved at low substrate temperature (150 °C) by standard Radio-frequency (13.56 MHz) Plasma Enhanced Chemical Vapor Deposition. Focus was on the influence of deposition pressure, inter-electrode distance (1.2 cm) and high power coupled to the plasma, on the hydrogen-to-silane dilution ratios (HD) necessary to achieve the amorphous-to-nanocrystalline phase transition and on the resulting film deposition rate. For each pressure and rf-power, there is a value of HD for which the films start to exhibit a certain amount of crystalline fraction. For constant rf-power, this value increases with pressure. Within the parameter range studied the deposition rate was highest (0.38 nm/s) for nc-Si:H films deposited at 6 Torr, 700 mW/cm2 using HD of 98.5 %. Decreasing the pressure to 3 Torr (1.5 Torr) and rf-power to 350 mW/cm2 using HD – 98.5 % deposition rate is 0.12 nm/s (0.076 nm/s). Raman crystalline fraction of these films is 72, 62 and 53 % for the 6, 3 and 1.5 Torr films, respectively.
TypeConference paper
URIhttp://hdl.handle.net/1822/11846
DOI10.1002/pssc.201000288
ISSN1610-1642
Publisher versionhttp://onlinelibrary.wiley.com
Peer-Reviewedno
AccessOpen access
Appears in Collections:CDF - CEP - Artigos/Papers (with refereeing)

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