1. Antenna-enhanced and polarization sensitive photoresponse in arrays of silicon P–i–N nanowires
- Author
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J Salfi, C Stewart, S V Nair, C Y Chen, S Yongshun, E Rusli, F K Lin, M Yu, N Singh, C F de Sousa, and H E Ruda
- Subjects
Science ,Physics ,QC1-999 - Abstract
We analyze a novel antenna effect that resonantly enhances the photocurrent response of end-contacted P–i–N junction nanowire gratings, due to coupling of incident radiation into the grating's multiple-scattering electromagnetic modes. Quantitative characterization of these resonances was performed by spectral and polarization-resolved photocurrent measurements on gratings with N = 500, 200 and 100 nanowires, aided by electron beam-induced current measurements, and in excellent agreement with electromagnetic scattering theory. Despite the small scattering cross-section of each nanowire, with triangular cross-section (height 8 nm, width 6 nm), the measured quality factor of the resonances Q ≈ 10 exceeds that of the empty SiO _2 cavity without degradation for gratings of as few as 100 nanowires. Photoresponse retains sinusoidal polarization anisotropy characteristic of single nanowires. We discuss strategies for improving Q and present a grating design tailoring resonant field enhancement at red, green or blue wavelengths, for three different grating periods of ℓ = 460, 400 and 320 nm.
- Published
- 2013
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