Black silicon n-Type photodiodes with high response over wide spectral range

Juha Heinonen, Mikko A. Juntunen, Hannu S. Laine, Ville Vähänissi, Päivikki Repo, Timo Dönsberg, Hele Savin*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

3 Citations (Scopus)
217 Downloads (Pure)


Commercial photodiodes suffer from reflection losses and different recombination losses that reduce the collection efficiency of photogenerated charge carriers. Recently, we realized a near-ideal silicon photodiode, which steps closer to the physical performance limits of silicon photodiodes than any other silicon photodiode realized before. Our device exhibits an external quantum efficiency above 95% over the wavelength range of 235-980 nm, and provides a very high response at incident angles of up to 70 degrees. The high quantum efficiency is reached by 1) virtually eliminating front surface reflectance by forming a "black silicon" nanostructured surface having dimensions in the range of wavelength of optical light and 2) using an induced junction for signal collection, formed by negatively charged alumina, instead of a conventional doped p-n junction. Here, we describe the latest efforts in further development of the photodiode technology. In particular, we report improvements both in the short wavelength response via better control of the surface quality, and superior response to photons with energies close to the silicon bandgap.

Original languageEnglish
Title of host publicationOptical Sensors 2017
ISBN (Electronic)978-1-5106-0964-8
Publication statusPublished - 2017
MoE publication typeA4 Conference publication
EventSPIE Optics + Optoelectronics - Prague, Czech Republic
Duration: 24 Apr 201727 Apr 2017

Publication series

NameSPIE Conference Proceedings
ISSN (Print)0277-786X


ConferenceSPIE Optics + Optoelectronics
Country/TerritoryCzech Republic


  • Alumina
  • Black Silicon
  • Broadband Photodiode
  • Ideal Photodiode
  • Induced Junction
  • Nanostructure
  • Photodiode
  • Quantum Efficiency
  • Silicon


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