Diffraction efficiency of plasmonic gratings fabricated by electron beam lithography using a silver halide film

• Published in: Journal of applied physics 2016-07, Vol.120 (4)
• Main Authors: Sudheer, Porwal, S., Bhartiya, S., Rao, B. T., Tiwari, P., Srivastava, Himanshu, Sharma, T. K., Rai, V. N., Srivastava, A. K., Naik, P. A.
• Format: Article
• Language: English
• Subjects: ABSORPTION; Applied physics; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DEPTH; DIFFRACTION; Diffraction efficiency; Diffraction theory; EFFICIENCY; Electron beam lithography; ELECTRON BEAMS; ELECTRONS; FABRICATION; GRATINGS; Gratings (spectra); KEV RANGE 10-100; Morphology; NANOPARTICLES; PEAKS; PLASMONS; RAMAN EFFECT; SCANNING ELECTRON MICROSCOPY; SILVER; SILVER HALIDES; SUBSTRATES; SURFACES; WAVELENGTHS
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4956438

The silver nanoparticle surface relief gratings of ∼10 μm period are fabricated using electron beam lithography on the silver halide film substrate. Morphological characterization of the gratings shows that the period, the shape, and the relief depth in the gratings are mainly dependent on the number of lines per frame, the spot size, and the accelerating voltage of electron beam raster in the SEM. Optical absorption of the silver nanoparticle gratings provides a broad localized surface plasmon resonance peak in the visible region, whereas the intensity of the peaks depends on the number density of silver nanoparticles in the gratings. The maximum efficiency of ∼7.2% for first order diffraction is observed for the grating fabricated at 15 keV. The efficiency is peaking at 560 nm with ∼380 nm bandwidth. The measured profiles of the diffraction efficiency for the gratings are found in close agreement with the Raman-Nath diffraction theory. This technique provides a simple and efficient method for the fabrication of plasmonic nanoparticle grating structures with high diffraction efficiency having broad wavelength tuning.