Structure%20of%20ZnO%20Nanorods%20using%20X-ray%20Diffraction

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Structure of ZnO Nanorods using X-ray Diffraction
Marci Howdyshell Albion College Mentors Bridget
Ingham and Michael Toney
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Introduction

• What?
• Zinc Oxide (ZnO)
• Why?
• Future applications of ZnO such as chemical
  sensing and optoelectronics
• The nanostructures enhance bulk characteristics
• The crystal structures of nanorods affect
  different properties
• We can look at orientations
• How?
• X-ray diffraction!

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The experiment
1/2 O2 H2O 2e - --gt 2OH - Zn2 2OH - --gt
ZnO 2 H2O
Schematic diagram of experimental setup CE is
counter electrode RE is reference electrode.
-The electrochemistry is controlled as the x-ray
beam reflects off the top of the quartz rod
(working electrode) and onto the detector.
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Diffraction Pattern
ZnO (102)

• n? 2dsin(?)
• (Q 2p/d)

ZnO (102)
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Making some sense of it
ZnO (102)
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Making some sense of it Intensity vs. ? Plots
Au (111)
ZnO (002)
ZnO (102)
ZnO (101)
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ZnO (102) Peak Width

• Width corresponds with how much the grain
  direction varies about the midpoint.

• Less negative potential means greater width and
  therefore more variation of grains about the
  midpoint

Potential (mV vs. Ag/AgCl/KCl
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Growth of ZnO Nanostructures
More negative thicker
Less negative thinner
Less negative potentials (-370 mV)
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SEM Images
-970 mV
-770 mV
-370 mV
-670 mV
65C, 5mM Zinc Nitrate,0.1M KCl
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Future Analysis

• Complement with electron microscopy
• Time series modeling
• XANES/EXAFS
• B. Ingham, B. N. Illy, J. R. Mackay, S. P. White,
  S.C. Hendy, M. P. Ryan, Mat. Res. Soc. Symp.
  Proc. 1017 (2007) DD12.16
• B. Ingham, B. N. Illy and M. P. Ryan, J. Phys.
  Chem. C (submitted)

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Acknowledgements

• Bridget Ingham, Michael Toney (SSRL)
• Benoit Illy and Mary Ryan (Imperial College
  London)
• DOE, SULI Program Coordinators