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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Resonant Cavity–Enhanced Photodiodes for Spectroscopy of C-H Bonds
AU - Bainbridge, Andrew
AU - Craig, Adam
AU - Al-Saymari, Furat
AU - Krier, Anthony
AU - Marshall, Andrew
PY - 2021/9/30
Y1 - 2021/9/30
N2 - Resonant cavity-enhanced photodiodes targeted within the spectral region of absorption by C-H bonds are demonstrated. The 3.0 – 3.3 μm region of the infrared spectrum contains many substances that are useful to measure spectroscopically. However, the measurement of individual substances requires a high spectral specificity, that is achieved by the resonant cavity photodiodes with spectral response widths of <40 nm . Two material systems are investigated for detection at this wavelength range—an InAs absorber on an InAs substrate and an InAsSb absorber lattice-matched to a GaSb substrate. The resonance wavelength of the InAs-based device responds at ≈3.3 μm, closely tuned to an absorption peak of methane to allow precise sensing of this gas. At 300 K a quantum efficiency of 52% is achieved, with a specific detectivity of 2.5×1010 cm√Hz/푊. The InAsSb-based device is sensitive at ≈3.7 μm, but the structure could be tuned to the methane absorption peak. Devices could be simply created to target other substances in the C−H absorption region by altering the layer thicknesses in the structure. Both structures can be used for spectrally specific gas sensing in this region of the infrared.
AB - Resonant cavity-enhanced photodiodes targeted within the spectral region of absorption by C-H bonds are demonstrated. The 3.0 – 3.3 μm region of the infrared spectrum contains many substances that are useful to measure spectroscopically. However, the measurement of individual substances requires a high spectral specificity, that is achieved by the resonant cavity photodiodes with spectral response widths of <40 nm . Two material systems are investigated for detection at this wavelength range—an InAs absorber on an InAs substrate and an InAsSb absorber lattice-matched to a GaSb substrate. The resonance wavelength of the InAs-based device responds at ≈3.3 μm, closely tuned to an absorption peak of methane to allow precise sensing of this gas. At 300 K a quantum efficiency of 52% is achieved, with a specific detectivity of 2.5×1010 cm√Hz/푊. The InAsSb-based device is sensitive at ≈3.7 μm, but the structure could be tuned to the methane absorption peak. Devices could be simply created to target other substances in the C−H absorption region by altering the layer thicknesses in the structure. Both structures can be used for spectrally specific gas sensing in this region of the infrared.
KW - gas sensing
KW - photodiodes
KW - resonant cavities
KW - spectroscopy
U2 - 10.1002/pssa.202100056
DO - 10.1002/pssa.202100056
M3 - Journal article
VL - 218
JO - physica status solidi (a)
JF - physica status solidi (a)
SN - 1862-6300
IS - 17
M1 - 2100056
ER -