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SUMMARY:Silane plasmas: a wonderful toolbox for the synthesis of nanomater
 ials
DTSTART:20151019T131500
DTEND:20151019T141500
DTSTAMP:20261003T205500Z
UID:9a715f64ce909f28ebec4b8ea0dd5a17371ebfb24f69b472bf307573
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Pere Roca i Cabarrocas\, LPICM CNRS Ecole Polytechnique\
 , Palaiseau France\nCrystalline silicon\, epitaxial growth. What are the r
 equired process conditions? Do you need high temperature? Is ultrahigh vac
 uum required?\nWhat about disordered materials? You may know that hydrogen
 ated amorphous and microcrystalline silicon thin films are routinely produ
 ced using silane plasmas at low temperature (~200 °C). But what are the d
 etails of the growth process? While SiH3 is often considered as the main r
 adical for the obtaining of such films\, we will see that moving the proce
 ss to conditions where silicon clusters and nanocrystals are produced in t
 he plasma can lead to high deposition rates and improved materials\, such 
 as hydrogenated polymorphous silicon and polycrystalline silicon. Moreover
 \, by changing the substrate from glass to crystalline silicon\, it is pos
 sible to produce epitaxial thin crystalline silicon films which can be tra
 nsferred to foreign substrates for flexible electronic devices [1]. Even m
 ore interesting\, this low temperature epitaxial process can be extended t
 o germanium and to SiGe alloys on c-Si but also on GaAs [2]. Last but not 
 least\, combining PECVD with low melting temperature metal particles such 
 as indium and tin opens the way to the growth of silicon nanowires\, which
  allow achieving efficient light trapping and carrier collection in radial
  junction solar cells [3] or even to grow in-plane nanowires [4].\n1. M. M
 oreno and P. Roca i Cabarrocas. EPJ Photovoltaics 1\, (2010) 10301.\n2. R.
  Cariou\, J. Tang\, N. Ramay\, R. Ruggeri\, and P. Roca i Cabarrocas. Sola
 r Energy Materials and Solar Cells 134 (2015) 15.\n3. S. Misra\, L. Yu\, M
 . Foldyna\, and P. Roca i Cabarrocas. Solar Energy Materials and Solar Cel
 ls 118 (2013) 90.\n4. L. Yu\, M. Xu\, J. Xu\, Z. Xue\, Z. Fan\, G. Picardi
 \, F. Fortuna\, J. Wang\, J. Xu\, Y. Shi\, K. Chen and P. Roca i Cabarroca
 s. Nano Letters 14 (2014)6469.\nBio: Prof. Pere Roca i Cabarrocas\, native
  of Catalonia\, is an Electrical Engineer from the “Universitat Politéc
 nica de Barcelona”. In 1984 he moved to Paris\, where he received his Ph
 D from University Paris VII in 1988. After a post-doc position in Princeto
 n University he joined the Laboratory of Physics of Interfaces and Thin Fi
 lms at Ecole Polytechnique where he holds a position as a CNRS director of
  research and as a professor. Since 2012 he is the director of LPICM. He h
 as thirty years of experience in the field of plasma deposition of silicon
  based thin films for large area electronic applications His topics cover 
 the study of RF discharges for the deposition of amorphous\, polymorphous 
 and microcrystalline silicon thin films. He has used in-situ diagnostic te
 chniques such as UV-visible ellipsometry\, Kelvin probe and time resolved 
 microwave conductivity to understand the growth of these materials and app
 ly them to the production of devices such as solar cells\, thin film trans
 istors\, particle detectors\, sensors\,… More recently he has been apply
 ing silicon nanocrystals synthesized in the plasma as building blocs for t
 he epitaxial growth of silicon thin films and Si/Ge quantum wells. On the 
 other hand\, he has extended the plasma processes to the growth of vertica
 l silicon nanowires for third generation solar cells and of horizontal one
 s for planar electronic applications\; both types of wires being achieved 
 at low temperature and in a single pump down process. He was the recipient
  of the Médaille Blondel in 2004\, of the Innovation Award at Ecole Polyt
 echnique in 2009 and the Silver medal from CNRS in 2011. He has over 380 p
 apers in peer reviewed journals and holds 31 patents.
LOCATION:MXF 1 https://plan.epfl.ch/?room==MXF%201
STATUS:CONFIRMED
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