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5.8 Conclusion tel-00916300, version 1 - 10 Dec 2013 Theoretical investigations reveal various interesting facts about the numerous factors that inuence emission. The simulations performed in this chapter clearly show the variation of pump prole with angle of incidence, thickness of the lm and complex refractive index. These variations of the pump prole inuence the excited emitter density, and therefore the emission intensity. The non-monotonous trend of emission intensity with total thickness, sublayer thickness, pattern number etc. caution us regarding the commonly used normalization to thickness of the PL intensity during analyses. Besides, the width and position of the emission peaks are inuenced by the optical cavity eects. Therefore, the interpretation of emission peak position and intensity only on the basis of the density of emitters such as Si-np and their size-distribution is insucient. A deep insight on the compexity of understanding the emission is detailed in this chapter. The presence of two emission peaks in SRSO/SiO 2 MLs is conrmed as the presence of two kinds of emitters. Following the analysis on SRSO/SiO 2 ML, the unattributed peak (1) in SRSO/SRSN is suggested to be the second kind of emitter in SRSO sublayer. Further investigations on SRSO/SiO 2 and SRSO/SRSN MLs are expected to reveal interesting informations on treating the PL spectra. 166
Conclusion and future perspectives Fullled thesis objectives tel-00916300, version 1 - 10 Dec 2013 A systematic study on the growth techniques and material properties was made towards fullling the four major objectives of this thesis. Therefore, the results of this thesis are also summarized into four parts as follows: 1. Material growth technique The rst major objective was to increase the density of Si-np in SRSO layers. This requires a higher incorporation of Si inside the SRSO layer during the sputtering process. In order to achieve this, two strategies were employed: Strategy 1: Varying the deposition parameters such as deposition temperature, hydrogen rate and power applied on the Si cathode in the already established reactive sputtering and co-sputtering approaches. Outcome: A temperature dependent growth mechanism was proposed, and it was shown that T d = 500°C favours the agglomeration of Si even during deposition, which is conrmed by characterization studies performed on those layers. This agglomeration of Si will serve as seeds for Si-np formation on further annealing. Strategy 2: Combining the advantages of reactive sputtering and co-sputtering approaches in favouring Si incorporation, and developing a new approach called as the Reactive co-sputtering. Outcome: High refractive indices were obtained, and the formation of Si-np in SRSO monolayers as well as SRSO sublayers in a ML conguration were witnesssed even in the as-grown state. It was seen that upon annealing, the Si-np density in SRSO reaches about 3 x 10 19 np/cm 3 in SRSO/SiO 2 MLs and about 10 20 np/cm 3 in SRSO/SRSN MLs thus fullling the rst objective of this thesis. 167
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UNIVERSITÉ de CAEN BASSE-NORMANDIE
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tel-00916300, version 1 - 10 Dec 20
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2.1.1 Radiofrequency Magnetron Reac
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3.21 Inuence of sublayer thicknesse
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Introduction State of the art tel-0
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as the thickness of the lm, the pat
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Chapter 1 Role of Silicon in Photov
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mono-, poly- and amorphous silicon,
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Figure 1.3: A typical solar cell ar
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occurance of this three body event
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Shockley-Queisser limit of 31% [Sho
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Figure 1.12: materials. Energy diag
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Background of this thesis: A new me
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Chapter 2 Experimental techniques a
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maximum power into the plasma. (a)
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Figure 2.2: Illustration of sample
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Ray Diraction, X-Ray Reectivity, El
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(a) Normal Incidence. (b) Oblique (
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to equation 2.4, when X-ray beam st
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investigation. This value is obtain
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e seen that large θ (here, θ is u
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Figure 2.12: Raman spectrometer-Sch
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Experimental set-up and working tel
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ˆ The presence of Si from SiO 2 or
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2.2.7 Spectroscopic Ellipsometry Pr
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k(E) = f j(ω − ω g ) 2 (ω −
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tel-00916300, version 1 - 10 Dec 20
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Figure 2.20: Schematic diagram of t
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Chapter 3 A study on RF sputtered S
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(a) Deposition rate. (b) Refractive
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Thus, by knowing the refractive ind
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P Ar (mTorr) P H2 (mTorr) r H (%) 1
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such a peak was witnessed in [Quiro
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the host SiO 2 matrix leading to an
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initiated in this thesis, for the g
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P Si (W/cm 2 ) x = 0/Si Bruggemann
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Figure 3.15: Absorption coecient cu
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Aim of the study To see the inuence
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It can be seen that there is a sign
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3.8.4 Inuence of SiO 2 barrier thic
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Chapter 4 A study on RF sputtered S
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4.2.2 Structural analysis (a) Fouri
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(a) FTIR spectra of NRSN, Si 3 N 4
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Figure 4.15: Absorption coecient sp
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A multilayer composed of 100 patter
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multilayered conguration. Therefore
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around 1250 cm −1 . The blueshift
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tel-00916300, version 1 - 10 Dec 20
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Page 159 and 160: function of wavelength consists of
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Page 189 and 190: Bibliography [Abeles 83] B. Abeles
Page 191 and 192: [Carlson 76] D. E. Carlson & C. R.
Page 193 and 194: [Di 10] D. Di, I. Perez-Wur, G. Con
Page 195 and 196: [Gritsenko 99] V. A. Gritsenko, K.
Page 197 and 198: [Kaiser 56] W. Kaiser, P. H. Kech &
Page 199 and 200: [Mandelkorn 62] J. Mandelkorn, C. M
Page 201 and 202: [Pavesi 00] L. Pavesi, L. D. Negro,
Page 203 and 204: [Sopori 96] B. L. Sopori, X. Deng,
Page 205 and 206: [Weng 93] Y. M. Weng, Zh. N. fan &
Page 207 and 208: and the tangential components of th
Page 209 and 210: Appendix II Trials σ em.max (x10
Page 211: Résumé tel-00916300, version 1 -
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