Films minces à base de Si nanostructuré pour des cellules ...

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LIST OF ABBREVIATIONS tel-00916300, version 1 - 10 Dec 2013 APT CA FG FTIR LTA ML NRSN PL PV QCE QD Si-np SRSN SRSO STA TEM XRD XRR Atom Probe Tomography Classical Annealing (1h-1100°C) Forming Gas Fourier Transform InfraRed spectroscopy Long Time Annealing (1h) MultiLayer Nitrogen-Rich Silicon Nitride PhotoLuminescence PhotoVoltaic Quantum Connement Eect Quantum Dots Silicon nanoparticles Silicon-Rich Silicon Nitride Silicon-Rich Silicon Oxide Short Time Annealing (1min-1000°C) Transmission Electron Microscope X-Ray Diraction X-Ray Reectivity xv
Introduction State of the art tel-00916300, version 1 - 10 Dec 2013 In the quest for new renewable sources of energy, the focus of research today is on cost-eective photovoltaic technologies with higher levels of eciency. The second generation thin lm solar cells were promising compared to the rst generation of bulk solar cells in reducing the manufacturing costs. But, the eciencies are lower since the thin lms in general cannot absorb eciently the solar spectrum without light trapping mechanisms. The combination of the third generation solar cell concepts and the second generation thin lm materials has been identied as a solution to economically meet the global energy needs. The major targets of the third generation photovoltaics (PV) are: ˆ to reduce the cost from 1$/watt of second generation PV to 0.50-0.20 $/watt by increasing the eciency and lowering the material need. ˆ to overcome the power loss mechanisms in single bandgap solar cells using approaches that eectively absorb photons below and above the bandgap of the solar cell material. Tandem cell is one of the third generation concepts that enables to absorb a wide range of solar spectrum by stacking individual cells with dierent bandgaps. The wide availability of the non-toxic Si, and its compatibility with the already existing technologies make All-Si tandem cell an attractive approach. Silicon, being an indirect semiconductor is not an ideal material in reducing the cost of solar cells because it requires about 125 micron thickness to absorb 90% of solar radiation, while in a direct bandgap material such as GaAs about 1 micron is sucient. The discovery of quantum connement eect in Si nanostructures resolves this problem arising from conventional c-Si solar cells, and therefore can be eciently incorporated in a tandem cell. The bandgap engineering is achieved by stacking quantum wells (QW) or quantum dots (QD) of Si with dielectric barriers which are also based on Si-compounds such as SiO 2 , Si 3 N 4 or SiC. With increasing QD density, the eective 1
Page 1 and 2: UNIVERSITÉ de CAEN BASSE-NORMANDIE
Page 3 and 4: tel-00916300, version 1 - 10 Dec 20
Page 5 and 6: 2.1.1 Radiofrequency Magnetron Reac
Page 11 and 12: 3.21 Inuence of sublayer thicknesse
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Page 21 and 22: as the thickness of the lm, the pat
Page 23 and 24: Chapter 1 Role of Silicon in Photov
Page 25 and 26: mono-, poly- and amorphous silicon,
Page 27 and 28: Figure 1.3: A typical solar cell ar
Page 29 and 30: occurance of this three body event
Page 33 and 34: Shockley-Queisser limit of 31% [Sho
Page 41 and 42: Figure 1.12: materials. Energy diag
Page 45 and 46: Background of this thesis: A new me
Page 47 and 48: Chapter 2 Experimental techniques a
Page 49 and 50: maximum power into the plasma. (a)
Page 51 and 52: Figure 2.2: Illustration of sample
Page 53 and 54: Ray Diraction, X-Ray Reectivity, El
Page 55 and 56: (a) Normal Incidence. (b) Oblique (
Page 57 and 58: to equation 2.4, when X-ray beam st
Page 59 and 60: investigation. This value is obtain
Page 61 and 62: e seen that large θ (here, θ is u
Page 63 and 64: Figure 2.12: Raman spectrometer-Sch
Page 65 and 66: Experimental set-up and working tel
Page 67 and 68: 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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tel-00916300, version 1 - 10 Dec 20
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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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tel-00916300, version 1 - 10 Dec 20
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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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tel-00916300, version 1 - 10 Dec 20
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It can be seen that there is a sign
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tel-00916300, version 1 - 10 Dec 20
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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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tel-00916300, version 1 - 10 Dec 20
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tel-00916300, version 1 - 10 Dec 20
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tel-00916300, version 1 - 10 Dec 20
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(a) FTIR spectra of NRSN, Si 3 N 4
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tel-00916300, version 1 - 10 Dec 20
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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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tion but within a dierence of one o
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sample peak 1 (eV) peak 2 (eV) peak
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(a) 1min annealing vs. T A . (b) 1h
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tel-00916300, version 1 - 10 Dec 20
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(a) Brewster incidence. (b) Normal
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tel-00916300, version 1 - 10 Dec 20
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increases for the 50 patterned samp
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- Peak (3) and (c): 1.8-1.95 eV Die
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4.10.2 Eect of Si-np Size distribut
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tel-00916300, version 1 - 10 Dec 20
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tel-00916300, version 1 - 10 Dec 20
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Chapter 5 Photoluminescence emissio
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As seen from gure 5.1, a part of th
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function of wavelength consists of
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tel-00916300, version 1 - 10 Dec 20
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In the case of our multilayers, the
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⎛ ⎜ ⎝ A ′ 2 B ′ 2 1 ⎞
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dN 3 dt = N 2 τ 23 − (σ em. φ
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Figure 5.12: The shapes of k(λ) an
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5.4 Discussion on the choice of inp
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tting operations show the presence
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(a) 270nm. (b) 300nm. tel-00916300,
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(a) σ emis.max. = 8.78 x 10 −18
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(a) 50(3/1.5) (b) 50(3/3) tel-00916
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(a) Integrated population of excite
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two kinds of emitters in SRSO subla
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Conclusion and future perspectives
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4. Investigating the origin of phot
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Bibliography [Abeles 83] B. Abeles
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[Carlson 76] D. E. Carlson & C. R.
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[Di 10] D. Di, I. Perez-Wur, G. Con
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[Gritsenko 99] V. A. Gritsenko, K.
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[Kaiser 56] W. Kaiser, P. H. Kech &
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[Mandelkorn 62] J. Mandelkorn, C. M
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[Pavesi 00] L. Pavesi, L. D. Negro,
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[Sopori 96] B. L. Sopori, X. Deng,
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[Weng 93] Y. M. Weng, Zh. N. fan &
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and the tangential components of th
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Appendix II Trials σ em.max (x10
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Résumé tel-00916300, version 1 -
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Films minces à base de Si nanostructuré pour des cellules ...

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