TY - JOUR
T1 - Optical properties and interparticle coupling of plasmonic bowtie nanoantennas on a semiconducting substrate
AU - Schraml, K.
AU - Spiegl, M.
AU - Kammerlocher, M.
AU - Bracher, G.
AU - Bartl, J.
AU - Campbell, T.
AU - Finley, J. J.
AU - Kaniber, M.
PY - 2014/7/23
Y1 - 2014/7/23
N2 - We present the simulation, fabrication, and optical characterization of plasmonic gold bowtie nanoantennas on a semiconducting GaAs substrate as geometrical parameters such as size, feed gap, height, and polarization of the incident light are varied. The surface-plasmon resonance was probed using white light reflectivity on an array of nominally identical, 35-nm-thick gold antennas. To elucidate the influence of the semiconducting, high-refractive- index substrate, all experiments were compared using nominally identical structures on glass. Besides a linear shift of the surface-plasmon resonance from 1.08 to 1.58 eV when decreasing the triangle size from 170 to 100 nm on GaAs, we observed a global redshift by 0.25 ± 0.05 eV with respect to nominally identical structures on glass. By performing polarization-resolved measurements and comparing results with finite-difference time-domain simulations, we determined the near-field coupling between the two triangles composing the bowtie antenna to be ∼8 times stronger when the antenna is on a glass substrate compared to when it is on a GaAs substrate. The results obtained have strong relevance for the integration of lithographically defined plasmonic nanoantennas on semiconducting substrates and therefore for the development of novel optically active plasmonic-semiconducting nanostructures.
AB - We present the simulation, fabrication, and optical characterization of plasmonic gold bowtie nanoantennas on a semiconducting GaAs substrate as geometrical parameters such as size, feed gap, height, and polarization of the incident light are varied. The surface-plasmon resonance was probed using white light reflectivity on an array of nominally identical, 35-nm-thick gold antennas. To elucidate the influence of the semiconducting, high-refractive- index substrate, all experiments were compared using nominally identical structures on glass. Besides a linear shift of the surface-plasmon resonance from 1.08 to 1.58 eV when decreasing the triangle size from 170 to 100 nm on GaAs, we observed a global redshift by 0.25 ± 0.05 eV with respect to nominally identical structures on glass. By performing polarization-resolved measurements and comparing results with finite-difference time-domain simulations, we determined the near-field coupling between the two triangles composing the bowtie antenna to be ∼8 times stronger when the antenna is on a glass substrate compared to when it is on a GaAs substrate. The results obtained have strong relevance for the integration of lithographically defined plasmonic nanoantennas on semiconducting substrates and therefore for the development of novel optically active plasmonic-semiconducting nanostructures.
UR - https://www.scopus.com/pages/publications/84904864167
U2 - 10.1103/PhysRevB.90.035435
DO - 10.1103/PhysRevB.90.035435
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AN - SCOPUS:84904864167
SN - 1098-0121
VL - 90
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 3
M1 - 035435
ER -