Supplemental Materials
Surface Plasmon Resonances of Ga Nanoparticle Arrays
M. Kang,1 T. W. Saucer,2 M. V. Warren,1 J. H. Wu,1 H. Sun,1 V. Sih,2 and R. S. Goldman1*
1
Department of Materials Science and Engineering
2
Department of Physics
University of Michigan, Ann Arbor, MI 48109-2136, USA
*rsgold@umich.edu
For transmission electron microscopy (TEM) studies, cross–sectional specimens of Ga
nanoparticle (NP) arrays on GaN surfaces were prepared by ion milling followed by lift-out
processing in a FEI Helios Nanolab 650 FIB. The sample was then mounted on a Mo grid and
ion polished to ~ 100 nm. TEM imaging and selected area diffraction (SAD) were carried out in
a JEOL 3011 operating at 300 kV.
Figure 1 presents (a) a bright-field TEM image and corresponding selected area diffraction
(SAD) patterns collected from (b) a FIB-patterned Ga NP and (c) the GaN substrate, in the
vicinity of the Ga NP. The SAD pattern from the Ga NP, shown in Fig. 1(b), presents a diffuse
ring corresponding to a mean interatomic distance of 2.79 Å, similar to the first nearest neighbor
Ga separation reported for α-Ga, 2.78 Å.1 For the GaN region, Fig. 1(c) reveals a single crystal
1
pattern with R1/R2 = 1.778 and θR1-R2 = 90°, similar to the [ 1 100] zone axis of a-plane wurtzite
GaN, with R(11 2 0)/R(0001) = 1.779 and θ(11 2 0)-(0001) = 90°.2
2
Supplemental Figure Caption
Supplemental Fig. 1 (a) Bright-field transmission electron micrograph of a FIB-fabricated Ga
nanoparticle (NP) on a GaN surface; corresponding SAD pattern collected from (b) a Ga NP and
(c) the GaN substrate, in the vicinity of the Ga NP.
3
Supplemental Fig. 1
4
References
1
A. Bererhi, L. Bosio, and R. Cortes, J. Non-Crystalline Solids 30, 253 (1979).
2
C. H. Shih, T. H. Huang, R. Schuber, Y. L. Chen, L. Chang, I. Lo, M. M. Chou, and D. M.
Schaadt, Nanoscale Res. Lett. 6, 425 (2011).
5