Journal ArticleDOI
Tunable photoluminescence from nc-Si/a-SiNx:H quantum dot thin films prepared by ICP-CVD
Basudeb Sain,Debajyoti Das +1 more
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TLDR
Intense visible photoluminescence tunable within 1.66-2.47 eV, under UV 325 nm excitation, was obtained from nanocrystalline silicon quantum dots obtained from the low temperature and single-step plasma processing and holds great promise for the fabrication of light-emitting devices and flexible flat panel displays.Abstract:
Intense visible photoluminescence (PL) tunable within 1.66–2.47 eV, under UV 325 nm excitation, was obtained from nanocrystalline silicon quantum dots (∼5.72–1.67 nm in diameter) embedded in amorphous silicon-nitride matrix (nc-Si/a-SiNx:H) prepared in RF-ICPCVD (13.56 MHz) at substrate temperatures between 400 to 150 °C. The dominant component of PL, having a narrow band width of ∼0.16–0.45 eV, originates from quasi-direct band-to-band recombination due to quantum confinement effect (QCE) in the nanocrystalline silicon quantum dots (nc-Si QDs) of appropriate size; however, the contribution of defects arose at lower substrate temperatures leading to asymmetric broadening. Intense atomic hydrogen flux in high-density inductively coupled plasmas (ICPs) provides a very high surface coverage, passivates well the nonradiative dangling bonds, and thereby favors the PL intensity. The average size of nc-Si QDs measured by HR-TEM appears consistent with similar estimates from Raman studies. The red shift of the Raman line and corresponding line broadening originates from the confinement of optical phonons within nc-Si QDs. Photoluminescence emerging from nc-Si/a-SiNx:H quantum dots obtained from the low temperature and single-step plasma processing holds great promise for the fabrication of light-emitting devices and flexible flat panel displays.read more
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Journal Article
Si quantum dots embedded in an amorphous SiC matrix : nanophase control by non-equilibrium plasma hydrogenation
TL;DR: Effective nanophase segregation at a low hydrogen dilution ratio of 4.0 leads to the formation of highly uniform Si QDs embedded in the amorphous SiC matrix, which is highly relevant to the development of next-generation photovoltaic solar cells, light-emitting diodes, thin-film transistors, and other applications.
Journal ArticleDOI
Electrical transport phenomena prevailing in undoped nc-Si/a-SiNx:H thin films prepared by inductively coupled plasma chemical vapor deposition
Debajyoti Das,Basudeb Sain +1 more
TL;DR: In this article, a comprehensive analysis on the electrical transport phenomena prevailing in undoped nc-Si/a-SiNx:H thin films prepared by inductively coupled plasma chemical vapor deposition and its correlation with the specific inhomogeneous structure, consisting of a mixture of different phases involving charge transfer by tunneling and thermionic emission or a connected network of aggregates of such components, has been made for deeper understanding.
Journal ArticleDOI
Conducting wide band gap nc-Si/a-SiC:H films for window layers in nc-Si solar cells
Debjit Kar,Debajyoti Das +1 more
TL;DR: In this paper, the authors developed a nc-Si/a-SiC:H hetero-structure wherein Si-C bonds in an amorphous matrix widen the optical band gap and the embedded high density Si ultranano-crystallites of mostly 〈220〉 crystallographic orientation provide high electrical conductivity as well as an enhanced optical band gaps due to a quantum size effect.
Journal ArticleDOI
Nanocrystalline silicon thin films from SiH 4 plasma diluted by H 2 and He in RF-PECVD
Subhashis Samanta,Debajyoti Das +1 more
TL;DR: In this paper, structural, optical and electrical properties of nanocrystalline silicon (nc-Si:H) films prepared at 250°C in capacitively-coupled RF-PECVD operated at 200 W of RF (13.56 ) power have been investigated as an effect of gas pressure variation in SiH 4 plasma diluted by equal amount of H 2 and He.
Journal ArticleDOI
Origin of visible photoluminescence from Si-rich and N-rich silicon nitride films
Irina N. Parkhomenko,L. Vlasukova,F. F. Komarov,O. Milchanin,M. A. Makhavikou,A. V. Mudryi,V. Zhivulko,Jerzy Żuk,P. Kopyciński,D. Murzalinov +9 more
TL;DR: In this article, the effect of composition and post-deposition annealing temperature on the SiN x light-emitting properties was investigated by the examination of photoluminescence.
References
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Journal ArticleDOI
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Journal ArticleDOI
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Journal ArticleDOI
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TL;DR: A new synthetic method was developed to produce robust, highly crystalline, organic-monolayer passivated silicon (Si) nanocrystals in a supercritical fluid by thermally degrading the Si precursor in the presence of octanol.