PHYS Ashutosh Rath - Homi Bhabha National Institute

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4.11 (a) SEM image taken at 54 o tilt from 50 nm Au/SiO x /Si(100)annealed at 975 o C, (b)corresponding XSEM image showing the contact angle between the faceted structure and the silicon. The schematic diagram shows the planes of the facets. . . . . . . . . . . . . . . . . . . . . . . 67 4.12 SEM image of the faceted gold particles on the carbon coated copper grid which are transferred from the silicon substrate by simple scratching method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.1 (a) BFTEM image of thermally grown as-deposited sample 2 nm Au/SiO x /Si(100) showing nanostructures (b) Corresponding SAD pattern showing the reflection of Au and silicon (c) Bright Field transmission electron micrograph at 850 o C (system-A1) (d) Corresponding selected area diffraction pattern and the ring (arrow marked) indicates the alloy formation [172]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 5.2 Real time bright field TEM image depicting the growth of a nano rectangle at the expense of gold nano particles (at 850 o C)[172]. . . . . 76 5.3 Bright field TEM image depicting the real time morphological changes during in situ heating (stabilized at the temp of 850 o C)[172]. . . . . . 77 5.4 (a) 2 nm Au/SiO 2 /Si(100) was ex-situ annealed (at 850 o C) under low vacuum (system-A2) and then seen in TEM at RT (b) corresponding SAD showing the reflection of gold and silicon [172]. . . . . . . . . . . 77 5.5 (a)Reflection high energy electron diffraction (RHEED) pattern showing clean reconstructed Si100-(2× 1) surface (b) Bright field TEM image shows the as deposited 2nm Au/Si(100) system. . . . . . . . . . . 78 5.6 Bright field TEM image of MBE grown 2 nm Au/Si(100) system annealed upto 500 o C inside (a) HV chamber and (c) LV chamber having average length 29.4 ± 1.5 nm (b) and 21.9 ± 1.2 nm (c) respectively. Inset figure shows the HRTEM image of one of the structures. . . . . 80 5.7 Bright field TEM image of MBE grown 2 nm Au/Si(100) system annealed upto 500 o C inside UHV chamber (a) (with air-exposed) and (c) without air exposed (in-situ) having average length 38.2 ± 1.4 nm (b), 56.4 ± 1.6 nm (d) respectively. Inset figure shows the HRTEM image of one of the structures. . . . . . . . . . . . . . . . . . . . . . . . . . 81 6.1 Schematic diagrams showing (a) the formation of gold silicide, (b) Ge nano structures and (c) Au-Ge bi-lobed structures on a Si substrate. . 86 xxiv
6.2 (a) As-deposited (sample A) showing gold nanostructures with corresponding high resolution image of one of the islands which is showing the d-spacing of Au(111) in the inset (b) SAD pattern showing reflection of both Si and Au, (c) bright field TEM image taken for the sample that was annealed at 500 o C in UHV chamber (sample B) with corresponding high resolution image of one of the single islands (inset), (d) SAD pattern showing the formation gold silicide along with the reflection Au and Si for the sample B, (e) bright field high resolution XTEM image of one of the nanostructure (sample B) showing inter-diffusion of Au into Si. (f) Depicts a SAD pattern taken at RT for the sample that was annealed in-situ TEM at 400 o C (sample G) and then cooled to RT. This shows no gold silicide formation at 400 o C [203]. . . . . . 89 6.3 Length distribution(fitted with Gaussian distribution) along 〈110〉 direction, of the sample shown in Fig. 6.2(c) which shows an average length of 48.1± 1.1 nm and (b) corresponding aspect ratio distribution and average aspect ratio is 0.99 ± 0.01 (here the histograms are fitted with Gaussian distribution to estimate the mean aspect ratio) (c) length distribution(fitted with Gaussian distribution) of the sample shown in Fig. 6.4(a) (for several frames) which shows the average length is 116 ± 1.8 nm and (d) corresponding aspect ratio distribution and average aspect ratio is 1.12 ± 0.03 (here the histograms are fitted with log−normal distribution to estimate the mean aspect ratio) [203]. 90 6.4 (a) SEM image taken at 0 o tilt (c) 54 o tilt; (b) depicts a XTEM image of epitaxially grown Ge nano structures and (d) for Au-Ge bilobed structures (sample C ) [203]. . . . . . . . . . . . . . . . . . . . . . . . 91 6.5 (a) Bright field TEM image of one of the bi-lobed Au-Ge nanostructures and (b) corresponding HRTEM images showing the Au-Ge alloy formation at the Au-Ge junction. (c) depicts STEM micrograph (sample C ) and (d) STEM-EDS elemental mapping (sample C )[203]. . . . 92 6.6 SEM image taken at RT after 5.0 nm Ge deposited on Au patterned substrate at (a) 400 o C (b) 500 o C and (c) 600 o C. This shows that no bi-lobed structures are formed at 400 o C. Corresponding RBS spectra in (d) show diffusion status of Au and Ge in Silicon at 400 o C (sample F1 ), 500 o C (sample F2 ) and 600 o C (sample F3 ) [203]. . . . . . . . . 93 xxv
Page 1: DYNAMIC AND STATIC TEM STUDIES ON T
Page 4 and 5: Declaration I, Ashutosh Rath, hereb
Page 6 and 7: a special word of appreciation for
Page 8 and 9: List of Publications 1. 1‡ Epitax
Page 10 and 11: Muller,M. Schowalter, R.Imlau, A. R
Page 12 and 13: Synopsis The thesis work involves a
Page 14 and 15: gold nanostructures on Si (100) sur
Page 16 and 17: Au-Ge bilobed structures were forme
Page 18 and 19: Contents Statement By Author Declar
Page 20 and 21: 8 Summary 107 A Table to summarize
Page 22 and 23: 3.1 As deposited MBE sample showing
Page 26 and 27: 6.7 Schematic diagram showing the A
Page 28 and 29: Introduction 2 giant magneto-resist
Page 30 and 31: Introduction 4 metals, in the case
Page 32 and 33: Introduction 6 and has been develop
Page 34 and 35: Experimental techniques 8 2.2 Thin
Page 36 and 37: Experimental techniques 10 for mono
Page 38 and 39: Experimental techniques 12 Layer pl
Page 40 and 41: Experimental techniques 14 signific
Page 42 and 43: Experimental techniques 16 Instrume
Page 44 and 45: Experimental techniques 18 Figure 2
Page 46 and 47: Experimental techniques 20 spherica
Page 52 and 53: Experimental techniques 26 a dynami
Page 54 and 55: Experimental techniques 28 that are
Page 56 and 57: Experimental techniques 30 componen
Page 60 and 61: Experimental techniques 34 electron
Page 64 and 65: Chapter 3 Temperature-dependent ele
Page 66 and 67: Temperature-dependent electron micr
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Temperature-dependent electron micr
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Chapter 4 Growth of Oriented Au Nan
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Growth of Oriented Au Nanostructure
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Structural modification of gold sil
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Nano scale phase separation in Au-G
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Gold assisted molecular beam epitax
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Summary 108 square /rectangular sha
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Summary 110 the annealed sample whi
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Bibliography [1] M. S. Gudiksen, L.
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BIBLIOGRAPHY 114 [32] Y. He, X. Yu
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BIBLIOGRAPHY 116 [67] M. Ohring Mat
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BIBLIOGRAPHY 118 [97] W. K. Chu, J.
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BIBLIOGRAPHY 120 [131] C. Suryanara
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BIBLIOGRAPHY 122 [167] C. R. Henry,
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BIBLIOGRAPHY 124 [201] E. Sutter an
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PHYS Ashutosh Rath - Homi Bhabha National Institute

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