Silicon photodiodes are widely used in applications that require the measurement of the intensity, colour and position of visible light. Silicon is an attractive material for these systems owing to its low cost, low noise, and easy on-chip integration with read-out electronics. However, silicon cannot effectively be used to detect near-infrared (NIR, at wavelengths of 700–1,000 nm) light and short-wave infrared (SWIR, 1,000–1,700 nm) light because of its bandgap of 1.12 eV, which is equivalent to a wavelength of 1,100 nm. Here, we report silicon photodiodes based on hourglass-shaped silicon nanowires that use whispering-gallery-mode resonances to enhance their photoresponse in the NIR–SWIR region of the spectrum. The upper, inverted nanocone of the nanowires increases absorption probability by extending the dwell time of NIR–SWIR photons via the generation of whispering-gallery-mode resonances, whereas the lower nanocone with its low reflectance reabsorbs the light incident from surrounding nanowires. Our devices exhibit a higher responsivity and external quantum efficiency than existing silicon photodiodes at 700–1,100 nm. Furthermore, the responsivity at 1,000 nm is similar to that of commercial InGaAs photodiodes and light at 1,400 nm can also be detected. Using our devices, we demonstrate a heart-rate measurement system that offers performance comparable to commercial setups.
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
Carey, J. E., Crouch, C. H., Shen, M. & Mazur, E. Visible and near-infrared responsivity of femtosecond-laser microstructured silicon photodiodes. Opt. Lett. 30, 1773–1775 (2005).
Juntunen, M. A. et al. Near-unity quantum efficiency of broadband black silicon photodiodes with an induced junction. Nat. Photon. 10, 777–781 (2016).
Michel, J., Liu, J. & Kimerling, L. C. High-performance Ge-on-Si photodetectors. Nat. Photon. 4, 527–534 (2010).
Chaisakul, P. et al. Integrated germanium optical interconnects on silicon substrates. Nat. Photon. 8, 482–488 (2014).
Luo, L.-B. et al. Light trapping and surface plasmon enhanced high-performance NIR photodetector. Sci. Rep. 4, 3914 (2014).
Sundararajan, S. P., Grady, N. K., Mirin, N. & Halas, N. J. Nanoparticle-induced enhancement and suppression of photocurrent in a silicon photodiode. Nano Lett. 8, 624–630 (2008).
Kelzenberg, M. D. et al. Enhanced absorption and carrier collection in Si wire arrays for photovoltaic applications. Nat. Mater. 9, 239–244 (2010).
Kim, S.-K. et al. Tuning light absorption in core/shell silicon nanowire photovoltaic devices through morphological design. Nano Lett. 12, 4971–4976 (2012).
Garin, M. et al. All-silicon spherical-Mie-resonator photodiode with spectral response in the infrared region. Nat. Commun. 5, 3440 (2014).
Yao, Y. et al. Broadband light management using low-Q whispering gallery modes in spherical nanoshells. Nat. Commun. 3, 664 (2012).
Song, B., Noda, S., Asano, T. & Akahane, Y. Ultra-high-Q photonic double heterostructure nanocavity. Nat. Mater. 4, 207 (2005).
Ko, M. et al. Periodically diameter-modulated semiconductor nanowires for enhanced optical absorption. Adv. Mater. 28, 2504–2510 (2016).
Fan, Z. et al. Ordered arrays of dual-diameter nanopillars for maximized optical absorption. Nano Lett. 10, 3823–3827 (2010).
Hua, B., Wang, B., Yu, M., Leu, P. W. & Fan, Z. Rational geometrical design of multi-diameter nanopillars for efficient light harvesting. Nano Energy 2, 951–957 (2013).
Konstantatos, G. Current status and technological prospect of photodetectors based on two-dimensional materials. Nat. Commun. 9, 5266 (2018).
Desiatov, B. et al. Plasmonic enhanced silicon pyramids for internal photoemission Schottky detectors in the near-infrared regime. Optica 2, 335–338 (2015).
Elbersen, R., Vijselaar, W., Tiggelaar, R. M., Gardeniers, H. & Huskens, J. Fabrication and doping methods for silicon nano- and mircopillar arrays for solar-cell applications: a review. Adv. Mater. 27, 6781–6796 (2015).
Garnett, E. & Yang, P. Light trapping in silicon nanowire solar cells. Nano Lett. 10, 1082–1087 (2010).
Solanki, C. S. Solar Photovoltaics: Fundamentals, Technologies and Applications Ch. 5 (PHI Learning, 2015).
Schmitt, S. W., Sarau, G. & Christiansen, S. Observation of strongly enhanced photoluminescence from inverted cone-shaped silicon nanostructures. Sci. Rep. 5, 17089 (2015).
Pala, R. A., White, J., Barnard, E., Liu, J. & Brongersma, M. L. Design of plasmonic thin-film solar cells with broadband absorption enhancements. Adv. Mater. 21, 3504–3509 (2009).
Brongersma, M. L., Cui, Y. & Fan, S. Light management for photovoltaics using high-index nanostructures. Nat. Mater. 13, 451–460 (2014).
Mokkapati, S., Beck, F. J., Polman, A. & Catchpole, K. R. Designing periodic arrays of metal nanoparticles for light-trapping applications in solar cells. Appl. Phys. Lett. 95, 053115 (2009).
Diedenhofen, S. L., Janssen, O. T. A., Grzela, G., Bakkers, E. P. A. M. & Rivas, J. G. Strong geometrical dependence of the absorption of light in arrays of semiconductor nanowires. ACS Nano 5, 2316–2323 (2011).
Zhou, L., Yu, X. & Zhu, J. Metal-core/semiconductor-shell nanocones for broadband solar absorption enhancement. Nano Lett. 14, 1093–1098 (2014).
Cho, Y., Gwon, M., Park, H.-H., Kim, J. & Kim, D.-W. Wafer-scale nanoconical frustum array crystalline silicon solar cells: promising candidates for ultrathin device applications. Nanoscale 6, 9568–9573 (2014).
Yin, J. et al. Self-assembled hollow nanosphere arrays used as low Q whispering gallery mode resonators on thin film solar cells for light trapping. Phys. Chem. Chem. Phys. 15, 16874–16882 (2013).
Yin, G., Manley, P. & Schmid, M. Light absorption enhancement for ultra-thin Cu(In1−xGax)Se2 solar cells using closely packed 2-D SiO2 nanosphere arrays. Sol. Energ. Mat. Sol. C. 153, 124–130 (2016).
Bosschaart, N., Edelman, G. J., Aalders, M. C. G., van Leeuwen, T. G. & Faber, D. J. A literature review and novel theoretical approach on the optical properties of whole blood. Lasers Med. Sci. 29, 453–479 (2014).
Palik, E. D., Handbook of Optical Constants of Solids (Academic, San Diego, 1998)
We acknowledge financial support from the Ministry of Science and ICT, Korea, under the ‘ICT Consilience Creative program’ (IITP-2019-2011-1-00783) and ‘Development of highly sensitive Si photodetector and optimization technique of its characterization of Nd:YAG laser’ (grant number 2018-0-01283) supervised by the Institute for Information and communications Technology Promotion (IITP), under the ‘Smart Industrial Energy ICT Convergence Consortium’ (NIPA-C1601-17-1007) supervised by the National IT Industry Promotion Agency (NIPA), and under the ‘Nano·Material Technology Development Program’ (2009-0082580) and ‘Development of high responsivity and high resolution silicon near-infrared sensor for autonomous vehicles using hourglass nanowire resonator structure’ (NRF-2019R1C1C1005692) supervised by the National Research Foundation of Korea (NRF). This work was also supported by MSS & TIPA under ‘Development of mass productive mid-temperature thermoelectric module based on top-down process technology’ (S2714114).
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Kim, K., Yoon, S., Seo, M. et al. Whispering gallery modes enhance the near-infrared photoresponse of hourglass-shaped silicon nanowire photodiodes. Nat Electron 2, 572–579 (2019). https://doi.org/10.1038/s41928-019-0317-z