Thermoelectric bolometers based on silicon membranes

Aapo Varpula, Andrey V. Timofeev, Andrey Shchepetov, Kestutis Grigoras, Jouni Ahopelto, Mika Prunnila

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

    1 Citation (Scopus)

    Abstract

    State-of-the-art high performance IR sensing and imaging systems utilize highly expensive photodetector technology, which requires exotic and toxic materials and cooling. Cost-effective alternatives, uncooled bolometer detectors, are widely used in commercial long-wave IR (LWIR) systems. Compared to the cooled detectors they are much slower and have approximately an order of magnitude lower detectivity in the LWIR. We present uncooled bolometer technology which is foreseen to be capable of narrowing the gap between the cooled and uncooled technologies. The proposed technology is based on ultra-thin silicon membranes, the thermal conductivity and electrical properties of which can be controlled by membrane thickness and doping, respectively. The thermal signal is transduced into electric voltage using thermocouple consisting of highly-doped n and p type Si beams. Reducing the thickness of the Si membrane improves the performance (i.e. sensitivity and speed) as thermal conductivity and thermal mass of Si membrane decreases with decreasing thickness. Based on experimental data we estimate the performance of these uncooled thermoelectric bolometers.
    Original languageEnglish
    Title of host publicationSmart Sensors, Actuators, and MEMS VIII
    EditorsMika Prunnila, Luis Fonseca, Erwin Peiner
    PublisherInternational Society for Optics and Photonics SPIE
    Volume10246
    ISBN (Electronic)9781510609938
    ISBN (Print)9781510609938
    DOIs
    Publication statusPublished - 1 Jan 2017
    MoE publication typeA4 Article in a conference publication
    EventSmart Sensors, Actuators, and MEMS VIII - Barcelona, Spain
    Duration: 8 May 201711 May 2017

    Publication series

    SeriesProceedings of SPIE
    Volume10246
    ISSN0277-786X

    Conference

    ConferenceSmart Sensors, Actuators, and MEMS VIII
    CountrySpain
    CityBarcelona
    Period8/05/1711/05/17

    Keywords

    • bolometers
    • silicon
    • thermoelectric materials
    • long wavelength infrared
    • sensors
    • photodetectors
    • doping
    • imaging systems
    • infrared detection
    • membrane
    • thermal detector
    • long-wave infrared
    • thermocouple
    • thermoelectric
    • OtaNano

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    Varpula, A., Timofeev, A. V., Shchepetov, A., Grigoras, K., Ahopelto, J., & Prunnila, M. (2017). Thermoelectric bolometers based on silicon membranes. In M. Prunnila, L. Fonseca, & E. Peiner (Eds.), Smart Sensors, Actuators, and MEMS VIII (Vol. 10246). [102460L] International Society for Optics and Photonics SPIE. Proceedings of SPIE, Vol.. 10246 https://doi.org/10.1117/12.2266554