DCU National Centre for Plasma Science and Technology

1
DCU - National Centre for Plasma Science and
Technology

• Wide bandgap materials and nanostructures
• Enda McGlynn
• DCU School of Physical Sciences/NCPST
• GE Visit 21st 25th February 2005

2
Collaborators (Wide bandgap materials and
nanostructures)

• DCU
• Academics
• Dr. Enda McGlynn
• Dr. Jean-Paul Mosnier
• Prof. Martin Henry
• Postdocs
• Dr. Jean-Rene DuClere
• Dr. RT Rajendra-kumar

• DCU
• Postgrads
• Mr. Ger Tobin
• Mr. James Fryar
• Ms. Deirdre McCabe
• Mr. Ricky OHaire
• Ms. Justyna Grabowska
• Mr. Alan Meaney

3
Wide bandgap materials and nanostructures

• To understand
• The optical and structural properties of wide
  bandgap materials and nanostructures
• The physics affecting these properties
• Methods by which these properties may be
  controlled via various growth techniques
• With the objective of
• Using these structures in novel photonic devices

4
Wide bandgap materials and nanostructures

• Materials system currently being studied
  intensively
• ZnO
• Bandgap of 3.3 eV
• Large exciton binding energy ( 60meV)
• Ability to grow self-organised nanostructured
  materials
• Lattice matched (ZnO) substrates are available (lt
  100 dislocations/cm2)
• ZnO is extremely radiation hard
• To date no really reliable, independently
  verified p-type doping

?
?
?
?
?
?
5
Wide bandgap materials and nanostructures

• Growth methods
• Pulsed Laser Deposition (PLD)
• Vapour Phase Transport

6
New SFI-funded PLD growth facility at DCU - study
of ZnO thin films and nanostructures

• 6 target carousel
• Independent target and substrate rotation
• Load lock for substrate
• UHV system to minimise background contamination

7
VPT growth of ZnO nanorods
8
Characterisation Techniques

• Photoluminesence (PL) 2K - 300K
• Reflectance 2K - 300K
• SEM CL-SEM 10K - 300K
• X-Ray Diffraction (XRD), q-2q, f-scan etc.
• Micro-Raman spectroscopy
• Hall (77K-500K)
• DLTS
• STM, AFM

9
Examples of nanostructures grown by VPT

• Results to appear in
• Physical Review B
• Journal of Materials Science Materials in
  Electronics
• Surface and Coatings Technology

10
Examples of horizontal nanowires grown by VPT
11
Potential interactions?

• ZnO nanostructures for field emission
  applications
• About 20 recent (from year 2000 on) papers on the
  topic of field emission from ZnO nanostructures
• Very wide spread of data (from the outsiders
  perspective)

12
ZnO nanostructures for field emission applications
From Li et al. Appl. Phys. Lett., Vol. 85, No.
4, 26 July 2004, p636 et seq.

• However, people have reported b up to 2000000!
• And a turn-on field at 1mA/cm2 of as low as 0.6
  V/mm
• CNT turn-on field 3V/mm ?
• CNT b 5000 ?

Problems with ZnO nanowires field emitters appear
to centre on stability (3 days) and the upper
current limit ( 10s of mA)
13
ZnO nanostructures for field emission applications

• What hasnt been tried (or tried often)?
• Most ZnO nanowires are unaligned and grown on Si,
  aligned nanowire studies are rarer
• Use of sapphire substrate, but with nanowires
  contacted by nanowall network

14
Chemical modification of ZnO nanowires (with
Prof. H. Vos, DCU SCS NCSR)

• Coating ZnO nanowires with various polypyridyl
  complexes, e.g ruthenium, may, via a charge
  transfer process, excite the polypyridyl complex
  emission and efficiently downconvert the ZnO
  emission photon energy.
• The coating and charge transfer efficiency are
  aided by the nanostructures large surface to
  volume ratio.
• Various chemical complexes may be engineered
  whose emission covers the visible range possibly
  leading to white light emission.

15
How to go forward

• Small scale projects
• Postgraduate (Ph.D.) student or postdoc
• Visits - GE to DCU ?
• Involvement in grant funding applications

16
Appendix Details of Publications
17
Field emission papers (1)

• 1. Chen L, Zhang GM, Wang MS, et al. Field
  emission from zinc oxide nanowires CHINESE
  PHYSICS 14 (1) 181-185 JAN 2005 Times Cited 0
• 2. Zhang GM, Zhang QF, Pei Y, et al. Field
  emission from nonaligned zinc oxide
  nanowires VACUUM 77 (1) 53-56 DEC 17 2004
  Times Cited 0
• 3. Yu K, Zhang YS, Xu RL, et al. Field emission
  behavior of cuboid zinc oxide nanorods on
  zinc-filled porous silicon SOLID STATE
  COMMUNICATIONS 133 (1) 43-47 JAN 2005 Times
  Cited 0
• 4. Banerjee D, Jo SH, Ren ZF Enhanced field
  emission of ZnO nanowires ADVANCED MATERIALS 16
  (22) 2028 NOV 18 2004 Times Cited 0
• 5. Kim DH, Jang HS, Lee SY, et al. Effects of gas
  exposure on the field-emission properties of ZnO
  nanorods NANOTECHNOLOGY 15 (11) 1433-1436 NOV
  2004 Times Cited 0
• 6. Kim DH, Lee HR Dependence of field emission of
  ZnO nanowire on vacuum pressure JOURNAL OF THE
  KOREAN PHYSICAL SOCIETY 45 (4) L803-L806 OCT
  2004 Times Cited 0
• 7. Maity R, Banerjee AN, Chattopadhyay KK
  Low-macroscopic field emission from fibrous ZnO
  thin film prepared by catalyst-free solution
  route APPLIED SURFACE SCIENCE 236 (1-4) 231-235
  SEP 15 2004 Times Cited 0
• 8. Kim DH, Lee HR Reversible response of field
  emission from ZnO nanowire to exposure to
  gases JOURNAL OF THE KOREAN PHYSICAL SOCIETY 45
  (2) L248-L251 AUG 2004 Times Cited 0
• 9. Jo SH, Banerjee D, Ren ZF Field emission of
  zinc oxide nanowires grown on carbon
  cloth APPLIED PHYSICS LETTERS 85 (8) 1407-1409
  AUG 23 2004 Times Cited 1
• 10. Li QH, Wan Q, Chen YJ, et al. Stable field
  emission from tetrapod-like ZnO
  nanostructures APPLIED PHYSICS LETTERS 85 (4)
  636-638 JUL 26 2004 Times Cited 0

18
Field emission papers (2)

• 11. Li SY, Lin P, Lee CY, et al. Field emission
  and photofluorescent characteristics of zinc
  oxide nanowires synthesized by a metal catalyzed
  vapor-liquid-solid process JOURNAL OF APPLIED
  PHYSICS 95 (7) 3711-3716 APR 1 2004 Times
  Cited 2
• 12. Xu CX, Sun XW, Chen BJ Field emission from
  gallium-doped zinc oxide nanofiber array APPLIED
  PHYSICS LETTERS 84 (9) 1540-1542 MAR 1 2004
  Times Cited 7
• 13. Jo SH, Lao JY, Ren ZF, et al. Field-emission
  studies on thin films of zinc oxide
  nanowires APPLIED PHYSICS LETTERS 83 (23)
  4821-4823 DEC 8 2003 Times Cited 8 14.
• Xu CX, Sun XW Field emission from zinc oxide
  nanopins APPLIED PHYSICS LETTERS 83 (18)
  3806-3808 NOV 3 2003 Times Cited 13
• 15. Tseng YK, Huang CJ, Cheng HM, et al.
  Characterization and field-emission properties of
  needle-like zinc oxide nanowires grown vertically
  on conductive zinc oxide films ADVANCED
  FUNCTIONAL MATERIALS 13 (10) 811-814 OCT 2003
  Times Cited 16
• 16. Zhu YW, Zhang HZ, Sun XC, et al. Efficient
  field emission from ZnO nanoneedle
  arrays APPLIED PHYSICS LETTERS 83 (1) 144-146
  JUL 7 2003 Times Cited 30
• 17. Dong LF, Jiao J, Tuggle DW, et al. ZnO
  nanowires formed on tungsten substrates and their
  electron field emission properties APPLIED
  PHYSICS LETTERS 82 (7) 1096-1098 FEB 17 2003
  Times Cited 22
• 18. Lee CJ, Lee TJ, Lyu SC, et al. Field emission
  from well-aligned zinc oxide nanowires grown at
  low temperature APPLIED PHYSICS LETTERS 81 (19)
  3648-3650 NOV 4 2002 Times Cited 82
• 19. Ohkawara Y, Naijo T, Washio T, et al. Field
  emission property of Al ZnO whiskers modified
  by amorphous carbon and related films JAPANESE
  JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS
  SHORT NOTES REVIEW PAPERS 40 (12) 7013-7017
  DEC 2001 Times Cited 13
• 20. Mao DS, Wang X, Li W, et al. Electron field
  emission from hydrogen-free amorphous
  carbon-coated ZnO tip array JOURNAL OF VACUUM
  SCIENCE TECHNOLOGY B 20 (1) 278-281 JAN-FEB
  2002 Times Cited 0

19
DCU papers on ZnO/ZnO nanostructures (past 2
years)

• Refereed
• E. de Posada, G. Tobin, E. McGlynn, J. G. Lunney,
  Pulsed laser deposition of ZnO and Mn-doped ZnO
  thin films, Applied Surface Science, 208209
  (2003) 589593.
• C. Roy, S. Byrne, E. McGlynn, J-P Mosnier, E. de
  Posada, D. OMahony, J. G. Lunney, M. Henry, B.
  Ryan, A.A. Cafolla, Correlation of Raman and
  X-Ray Diffraction Measurements of Annealed Pulsed
  Laser Deposited ZnO Thin Films, Thin Solid Films,
  436 (2003) 273276.
• Enda McGlynn, James Fryar, Martin O. Henry,
  Jean-Paul Mosnier, James G. Lunney, Donagh O
  Mahony, Eduardo dePosada, Exciton-Polariton
  Behaviour in Bulk and Polycrystalline ZnO,
  Physica B, 340-342C (2003), 230 234.
• G. Tobin, E. McGlynn, M.O. Henry, J.P. Mosnier,
  J.G. Lunney, D. O Mahony, E. dePosada,
  Ultraviolet Stimulated Emission from Bulk and
  Polycrystalline ZnO Thin Films with Varying Grain
  Sizes, Physica B, 340-342C (2003), 245 249.
• D. McCabe, K. Johnston, M.O. Henry, E. McGlynn,
  E. Alves, J.J. Davies, Optical Absorption of a
  Li-Related Impurity in ZnO, Physica B, 340-342C
  (2003), 225 229.
• J. Fryar, E. McGlynn, M.O. Henry, A.A. Cafolla,
  C.J. Hanson, Excitonic Properties of the Polar
  Faces of Bulk ZnO after Wet Etching, Physica B,
  340-342C (2003), 210 215.
• E. McGlynn, J. Fryar, G. Tobin, C. Roy, M.O.
  Henry, J-P. Mosnier, E. dePosada, J.G. Lunney,
  Effect of Polycrystallinity on the Optical
  Properties of Highly Oriented ZnO Grown by Pulsed
  Laser Deposition, Thin Solid Films, 458 (2004),
  330335.
• D. McCabe, K. Johnston, M.O. Henry, E. McGlynn,
  E. Alves, J.J. Davies, Erratum to Optical
  Absorption of a Li-Related Impurity in ZnO,
  Physica B, 351 (2004), 227.
• J. Fryar, E. McGlynn, M. O. Henry, A. A. Cafolla,
  C.J. Hanson, Dominant role of adsorbed fluid
  layers on the polar surfaces of ZnO in ambient
  atmospheric conditions, Nanotechnology, 15 (2004)
  1797-1801.

20
DCU papers on ZnO/ZnO nanostructures (past 2
years)

• Book Chapters
• E. McGlynn, J.Fryar, G.Tobin, C. Roy, S. Byrne,
  J-P Mosnier, E. de Posada, D. OMahony, J. G.
  Lunney, M.O. Henry, Optical Properties of
  Nanocrystalline ZnO Thin Films Grown using Pulsed
  Laser Deposition. Accepted for publication as an
  invited submission to the series Progress in
  Condensed Matter Physics, edited by F. Columbus,
  Nova Science Publishers.
• In press/submitted
• J.-R. Duclère, R. OHaire, A. Meaney, K.
  Johnston, I. Reid, G. Tobin, J.-P. Mosnier, M.
  Guilloux-Viry, E. McGlynn, M.O. Henry,
  Fabrication of P-type doped ZnO thin films using
  pulsed laser deposition for device applications,
  accepted for publication in Journal of Materials
  Science Materials in Electronics.
• J. Grabowska, K. K. Nanda, E. McGlynn, J.-P.
  Mosnier, M. O. Henry, Studying the growth
  conditions, the alignment and structure of the
  ZnO nanorods, accepted for publication in Surface
  and Coatings Technology.
• J. Grabowska, A. Meaney, K.K. Nanda, J.-P.
  Mosnier, M.O. Henry, J.-R. Duclère, E.McGlynn,
  Surface excitonic emission and quenching effects
  in ZnO nanowire/nanowall systems limiting
  effects on device potential, accepted for
  publication in Physical Review B.
• Th. Agne, M. Dietrich, H. Wolf, Th. Wichert, K.
  Johnston, D. McCabe, M.O. Henry, E. McGlynn,
  ISOLDE Collaboration, The Origin of the Green
  Band in Zinc Oxide. Submitted to Physical Review
  Letters.
• J. Grabowska, K.K. Nanda, E. McGlynn, J.-P.
  Mosnier, M.O. Henry, A. Beaucamp, A. Meaney,
  Synthesis and photoluminescence of ZnO nanowires
  / nanorods, submitted to Journal of Materials
  Science Materials in Electronics.
• Karl Johnston, Martin O. Henry, Deirdre McCabe,
  Enda McGlynn, Marc Dietrich, ISOLDE
  collaboration, Matthew Xia, Identifcation of
  Donor-Related Impurities in ZnO using Radiotracer
  Techniques, submitted to Physical Review B.
• J.-R. Duclère, C. Mc Loughlin, J. Fryar, R.
  OHaire, M. Guilloux-Viry, A. Meaney, A. Perrin,
  E. McGlynn, M.O. Henry, J.-P. Mosnier, High
  optical quality of ZnO thin films grown on Pt
  (111) epitaxial electrodes by pulsed laser
  deposition, submitted to Thin Solid Films.