Research progress and findings as presented at the International Conference on the Application of Accelerators in Research and Industry (CAARI 2016).

1. Synthesis and Characterization of
Au-Zn Nanoparticle Implants in
Sapphire
Daniel Scott, Emmanuel Epie, Wei-Kan Chu
Department of Physics, Texas Center for Superconductivity
University of Houston
Presented at CAARI 2016

2. Background
● Abundant ongoing research in nanomaterials
○ Many factors affect nanoparticle properties (size, structure, material, distribution)
● Applications
○ Sensors, imagers, optical switches
● Little to no material on Au-Zn NP alloys
● Can a Au-Zn NP alloy be synthesized via dual ion implantation in
sapphire? What mechanisms exist to alter the optical properties of these
NP?

3. Background (continued)
● Surface Plasmon Resonance (SPR)
○ Oscillation of conduction electrons
○ Impacted by dielectric (particle & ambient), structure, size
● Track formation may impact nanoparticle growth1
○ Implantation order (Au+Zn or Zn+Au) may lead to different results
● Annealing may offer control of optical responses:
○ Alloy (phase and structure)
○ NP size
1
Wang, Jun, et al. (See References)

4. Method
● Implantation of Au- and ZnO- ions in sapphire (Al2
O3
)
● Samples for: Au, Zn, Au+Zn, Zn+Au
● Optical measurements via spectrophotometer
○ Cary 5000 UV-vis-23 NIR spectrophotometer
● Annealings under Ar in a quartz tube
● NP size estimates by GIXRD
○ D/Max-RA X-ray spectrometer (Rigaku)

5. Parameters
● 60 keV (Au and ZnO)
● For adequate track formation:1
○ Au (Fluence 3x1016
/ cm2
)
○ Zn (Fluence 2.5x1016
/ cm2
)
● SRIM2
(range, sputtering, etc.)
● Two hour annealings at:
○ 400°C & 600°C
Concentration vs depth created using formula from 1 Wang, Jun, et al.

6. Unannealed Samples
Absorbance peaks:
Zn N/A
Au 552 nm
Au+Zn 530 nm
Zn+Au 434 nm

7. Annealing (Zn+Au)
SPR Peaks:
Unannealed 434 nm
400°C 514 nm
600°C 549 nm

8. Annealing (Au+Zn)
SPR Peaks:
Unannealed 530 nm
400°C 530 nm
600°C 531 nm

9. Data
SPR Peaks Au Au+Zn Zn+Au
Unannealed 552 nm 530 nm 434 nm
400°C 553 nm 530 nm 514 nm
600°C 558 nm 531 nm 549 nm

10. Analysis
● Possible explanations of shift:
○ Change in ambient dielectric
○ Crystalline stress
○ NP size
○ Alloy formation

11. Dielectric/Stress?
Could these account for the results?
○ In both cases, look towards differences
in Zn+Au and Au+Zn
Peak
Au 552 nm
Au+Zn 530 nm
Zn+Au 434 nm

12. Size?
Approximate nanoparticle sizes (diameter) as determined
by GIXRD and Debye-Scherrer Formula
Diameters Au Au+Zn Zn+Au
Unannealed 2.7 nm 1.7 nm 2.2 nm
400°C 2.7 nm 1.9 nm 3.1 nm
600°C 2.8 nm 2.2 nm 3.8 nm
*Note: Machine broadening not accounted for. Sizes are taken as approximations, not exact, and are most
useful in showing the relative differences in size between samples. Diameters are lower bounds.

13. DDSCAT3
Simulated Peak Absorbance Au in Sapphire
r = 1 nm 558 nm
r = 2 nm 559 nm
r = 4 nm 560 nm
Recall:
Experimental absorbance peak of Au Sample: 552 nm

14. Conclusion:
Key Results:
● Optical responses manipulatable through annealing
● Implantation order affects material synthesized
● Synthesis of Au-Zn metallic nanoparticle alloy
○ Dielectric, size, and stress do not explain results
Future Research:
● TEM
● Nanoparticle structural analysis
● Attempt at confirming alloy formation and identifying particular alloy
Peak
Au 552 nm
Au+Zn 530 nm
Zn+Au 434 nm

15. References
1
Wang, Jun, Guangyi Jia, Bei Zhang, Huixian Liu, and Changlong Liu. "Formation and Optical Absorption Property of Nanometer Metallic
Colloids in Zn and Ag Dually Implanted Silica: Synthesis of the Modified Ag Nanoparticles." J. Appl. Phys. Journal of Applied Physics
113.3 (2013): 034304.
2
SRIM, the stopping and range of ions in matter (2008) by J. F. Ziegler, J. P. Biersack, Matthias D. Ziegler
3
Draine, B.T., & Flatau, P.J., "Discrete dipole approximation for scattering calculations", J. Opt. Soc. Am. A, 11, 1491-1499 (1994)

16. Acknowledgements
Department of Physics & Texas Center for Superconductivity
(University of Houston)
Faculty Mentor: Dr. Wei-Kan Chu
Co-author: Emmanuel Epie