Abstract

The performance of infrared (IR) sensing bimaterial cantilevers depends upon the thermal, mechanical and optical properties of the cantilever materials. This paper presents bimaterial cantilevers that have a layer of black silicon nanocone arrays, which has larger optical absorbance and mechanical compliance than single crystal silicon. The black silicon consists of nanometer-scale silicon cones of height 104-336 nm, fabricated using a three-step O 2-CHF3-Ar + Cl2 plasma process. The average cantilever absorbance was 0.16 over the 3-10 μm wavelength region, measured using a Fourier transform infrared (FTIR) microspectrometer. The measured cantilever responsivity to incident IR light compares well to a model of cantilever behavior that relate the spectral absorbance, heat transfer, and thermal expansion. The model also provides further insights into the influence of the nanocone height on the absorbance and responsivity of the cantilever. Compared to a cantilever with smooth single crystal silicon, the cantilever with black silicon has about 2× increased responsivity. The nanocone array fabrication technique for silicon bimaterial cantilevers presented here could be applied to other IR sensors.

Original languageEnglish (US)
Pages (from-to)143-148
Number of pages6
JournalSensors and Actuators, A: Physical
Volume199
DOIs
StatePublished - Jul 5 2013

Keywords

  • Absorbance
  • Bimaterial
  • Black silicon
  • Fourier transform infrared (FTIR)
  • Infrared
  • Microcantilever
  • Nanocone arrays
  • Thermomechanical

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials
  • Metals and Alloys
  • Surfaces, Coatings and Films
  • Instrumentation

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