TY - JOUR
T1 - Evolution of ternary AuAgPd nanoparticles by the control of temperature, thickness, and tri-layer
AU - Kunwar, Sundar
AU - Pandey, Puran
AU - Sui, Mao
AU - Bastola, Sushil
AU - Lee, Jihoon
N1 - Publisher Copyright:
© 2017 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2017/11/4
Y1 - 2017/11/4
N2 - Metallic alloy nanoparticles (NPs) possess great potential to enhance the optical, electronic, chemical, andmagnetic properties for various applications by the control ofmorphology and elemental composition. This work presents the fabrication of ternary AuAgPd alloy nanostructures on sapphire (0001) via the solid-state dewetting of sputter-deposited tri-metallic layers. Based on the systematic control of temperature, thickness, and deposition order of tri-layers, the composite AuAgPd alloy nanoparticles (NPs) with various shape, size, and density are demonstrated. The metallic tri-layers exhibit various stages of dewetting based on the increasing growth temperatures between 400 and 900 °C at 15 nm tri-layer film thickness. Specifically, the nucleation of tiny voids and hillocks, void coalescence, the growth and isolated nanoparticle formation, and the shape transformation with Ag sublimation are observed. With the reduced film thickness (6 nm), tiny alloy NPs with improved structural uniformity and spatial arrangement are obtained due to enhanced dewetting. The growth trend of alloy NPs is drastically altered by changing the deposition order of metallic tri-layers. The overall evolution is governed by the surface diffusion and inter-mixing of metallic atoms, Rayleigh-like instability, surface and interface energy minimization, and equilibrium state of the system. The UV-VIS-NIR reflectance spectra reveal the formation of an absorption band and reflectance maxima at specific wavelengths based on the morphology and composition of AuAgPd alloy NPs. In addition, Raman spectra analysis shows the modulation of intensity and peak position of natural vibration modes of sapphire (0001).
AB - Metallic alloy nanoparticles (NPs) possess great potential to enhance the optical, electronic, chemical, andmagnetic properties for various applications by the control ofmorphology and elemental composition. This work presents the fabrication of ternary AuAgPd alloy nanostructures on sapphire (0001) via the solid-state dewetting of sputter-deposited tri-metallic layers. Based on the systematic control of temperature, thickness, and deposition order of tri-layers, the composite AuAgPd alloy nanoparticles (NPs) with various shape, size, and density are demonstrated. The metallic tri-layers exhibit various stages of dewetting based on the increasing growth temperatures between 400 and 900 °C at 15 nm tri-layer film thickness. Specifically, the nucleation of tiny voids and hillocks, void coalescence, the growth and isolated nanoparticle formation, and the shape transformation with Ag sublimation are observed. With the reduced film thickness (6 nm), tiny alloy NPs with improved structural uniformity and spatial arrangement are obtained due to enhanced dewetting. The growth trend of alloy NPs is drastically altered by changing the deposition order of metallic tri-layers. The overall evolution is governed by the surface diffusion and inter-mixing of metallic atoms, Rayleigh-like instability, surface and interface energy minimization, and equilibrium state of the system. The UV-VIS-NIR reflectance spectra reveal the formation of an absorption band and reflectance maxima at specific wavelengths based on the morphology and composition of AuAgPd alloy NPs. In addition, Raman spectra analysis shows the modulation of intensity and peak position of natural vibration modes of sapphire (0001).
KW - Alloy nanoparticles
KW - AuAgPd alloys
KW - Plasmonics
KW - Sapphire (0001)
KW - Solid-state dewetting
UR - http://www.scopus.com/inward/record.url?scp=85033576199&partnerID=8YFLogxK
U2 - 10.3390/met7110472
DO - 10.3390/met7110472
M3 - Article
AN - SCOPUS:85033576199
SN - 2075-4701
VL - 7
JO - Metals
JF - Metals
IS - 11
M1 - 472
ER -