A room-temperature mid-infrared photodetector for on-chip molecular vibrational spectroscopy
Applied Physics Letters
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Zheng, B., Zhao, H., Cerjan, B., Yazdi, S., Ringe, E., Nordlander, P., & Halas, N. (2018). A room-temperature mid-infrared photodetector for on-chip molecular vibrational spectroscopy. Applied Physics Letters, 113 (10) https://doi.org/10.1063/1.5045663
Infrared (IR) photodetection is of major scientific and technical interest since virtually all molecules exhibit characteristic vibrational modes in the mid-infrared region of the spectrum, giving rise to molecular spectroscopy and chemical imaging in this wavelength range. High-resolution IR spectroscopies, such as Fourier Transform IR spectroscopy, typically require large, bulky optical measurement systems and expensive photodetector components. Here, we present a high-responsivity photodetector for the mid-IR spectral region which operates at room temperature. Fabricated from silicon and aluminum, the photodetection mechanism is based on free carrier absorption, giving rise to a photoresponse rivalling commercially available cooled IR photodetectors. We demonstrate that infrared spectra of molecules deposited on this detector can be obtained by a direct electrical read-out. This work could pave the way for simple, fully integrated chemical sensors and other applications, such as chemical imaging, which would benefit from the combination of mid-IR detection, room-temperature operation, and ultracompact portability.
External DOI: https://doi.org/10.1063/1.5045663
This record's URL: https://www.repository.cam.ac.uk/handle/1810/285519
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