Technology Explained

Behind the superior performance of ElFys Photodetectors

photoresponse plot

Nearly Ideal Photoresponse over a Wide Spectral Range

Our photodetectors [1] have nearly ideal photoresponse from 200 nm to 950 nm, with ≥ 96% external quantum efficiency (certified by PTB, The National Metrology Institute of Germany).

The collection efficiency is enhanced by employing a surface nano-structuring technique combined with an atomic layer deposited coating. The certified photoresponse curve and comparison to other state-of-the-art pn-junction silicon photodiodes is shown on the side. Ideal photoresponse corresponding to 100% EQE is also shown for reference. Our technology is protected by the U.S. and elsewhere for ElFys Oy.

eqe plot

Exceptional Photoresponse in the Ultraviolet

The highly effective surface passivation technology eliminates surface recombination. In combination with suppression of the dead layer, it significantly boosts the collection efficiency of signal charges generated really close to the photodiode top surface, yielding an exceptional over 100% quantum efficiency for ultraviolet light.

The photoresponse is 2 times higher than other state-of-the-art technologies at 240 nm, as seen by the certified photoresponse in ultraviolet region and its comparison to state-of-the-art pn-junction silicon photodiodes shown on the side. The ideal photoresponse corresponding to 100% EQE is also shown for reference. See also References [1-7] or contact us for further details.

extra low reflectance

Ultra-Wide Sensing Angle with Extremely High Absorbance (> 95% @ 60°)

The black silicon surface combined with a tailored atomic layer deposited coating layer greatly enhances the surface absorbance for an extended range of sensing angles, with single-digit reflectance up to 1000 nm and 60° incident angle.

The angle-dependent surface reflectance of our photodetectors is shown on the side, for sensing angles from 10° to 70°.

Virtual Patent Marking

The following products are protected by patents in the U.S. and elsewhere for ElFys Oy. This website is provided to satisfy the virtual patent marking provisions of various jurisdictions including the virtual patent marking provisions of the America Invents Act and provide notice under 35 U.S.C. §287(a). The following list of products and patents may not be all inclusive. For example, some products listed here may be covered by patents in the United States and elsewhere that are not listed, and other products not listed here may be protected by one or more patents in the United States and elsewhere.

Product Name

Patent Number

PD1sM, PD1sH, PD4sM, PD4sH, PD25sM, PD25sH, PD100sM, PD100sH

US9882070, US10950737, FI127794, CN110326116B, JP7110213B2

PD4sMG, PD4sHG, PD5sMG, PD5sHG, PD25sMG, PD25sHG, PD100sMG, PD100sHG

US9882070, US10950737, FI127794, CN110326116B, JP7110213B2

SM322, SM446

US9882070, US10950737, FI127794, CN110326116B, JP7110213B2

References

[1] M. A. Juntunen, J. Heinonen, V. Vähänissi, P. Repo, D. Valluru, and H. Savin, “Near-unity quantum efficiency of broadband black silicon photodiodes with an induced junction”. Nature Photonics, 2016

[2]  M. A. Juntunen, J. Heinonen, H. S. Laine, V. Vähänissi, P. Repo, A. Vaskuri and H. Savin, ”N-type Induced junction Black Silicon photodiode for UV detection”.Proc. SPIE 10249, Integrated Photonics: Materials, Devices, and Applications IV, 2017

[3]  T. Tsang, A. Bolotnikov, A. Haarahiltunen and J. Heinonen, "Black Silicon Photodiodes for VUV Detection," 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), Manchester, UK, 2019

[4] M. Garin, J. Heinonen, L. Werner, T.P. Pasanen, V. Vähänissi, A. Haarahiltunen, M. Juntunen and H. Savin, “Black-silicon ultraviolet photodiodes achieve external quantum efficiency above 130%”, Physical Review Letters 125, 2020

[5] T. Tsang, A. Bolotnikov, A. Haarahiltunen, J. Heinonen, "Quantum efficiency of black silicon photodiodes at VUV wavelengths", Optics Express 28, 2020

[6] J. Heinonen, C. Modanese, A. Haarahiltunen, H. Kettunen, M. Rossi, J. Jaatinen, M. A. Juntunen, "Results on radiation hardness of black silicon induced junction photodetectors from proton and electron radiation", IEEE Transactions on Electron Devices, 2020

[7] J. Heinonen, C. Modanese, A. Haarahiltunen, H. Kettunen, M. Rossi, J. Jaatinen, M. A. Juntunen, "Results on radiation hardness of black silicon induced junction photodetectors from proton and electron radiation", Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 977, 2020

[8] J. Heinonen, A. Haarahiltunen, M. Dov Serue, V. Vähänissi, T. P. Pasanen, H. Savin, L. Werner, M. A. Juntunen, "High-sensitivity NIR photodiodes using black silicon", Proceedings Volume 11276, Optical Components and Materials XVII; 112760G, 2020

[9] T. Tsang, A. Bolotnikov, A. Haarahiltunen, J. Heinonen, “Quantum efficiency of black silicon photodiodes at VUV wavelengths”, Optics Express 28, 2020

[10] J. Heinonen, Pasanen Toni P., Vähänissi Ville, M.A. Juntunen, Savin  “Modeling field-effect in black silicon and its impact on device performance”  EEE Transactions on Electron Devices, 2020 

[11] J. Heinonen, A. Haarahiltunen, H. Kettunen, J. Jaatinen, M. Rossi, J. Heino, H. Savin, M. A. Juntunen, "Improved stability of black silicon detectors using aluminum oxide surface passivation," Proc. SPIE 11852, International Conference on Space Optics, 2021

[12] J. Heinonen, A. Haarahiltunen, M. Serué, D. Kriukova, V. Vähänissi, T. Pasanen, H. Savin, M. Juntunen,  ”Temperature dependency of responsivity and dark current of nearly ideal black silicon photodiodes”  Proceedings of SPIE 11682, Optical Components and Materials XVIII,  2021

[13] J. Heinonen, A. Haarahiltunen, V. Vähänissi, T. Pasanen, H. Savin, M.A. Juntunen, ”Effect of anode sheet resistance on rise time of black silicon induced junction photodiodes”  Proceedings of SPIE 11997, Optical Components and Materials XIX, 2022

[14] J. Heinonen, “High-sensitivity photodiodes using black silicon and induced junction”, Aalto University publication series DOCTORAL THESES, 36/2022

[15] J. Heinonen, A. Haarahiltunen, V. Vähänissi, T. Pasanen, H. Savin, J. Toivanen, M.A. Juntunen, ”Spatial uniformity of black silicon induced junction photodiode responsivity”  Proceedings of SPIE 12417, Optical Components and Materials XX, 2023

[16] T. Pasanen, J. Heinonen, M. Serué, A. Haarahiltunen, ”Speed and responsivity optimization for near-infrared silicon photodetectors with black surface” Proceedings of OPTRO24, 11th International Symposium on Optronics in Defence and Security, 2024