Ferroelectric Gating of Narrow Band-Gap Nanocrystal Arrays with Enhanced Light Matter Coupling
Résumé
As narrow band gap nanocrystals become a viable building block for the design of infrared sensors, device design needs to match with their actual operating conditions. While in the near IR and shortwave infrared room temperature operation have been demonstrated, longer wavelengths still require low temperature operation requiring specific design. Here, we discuss how field-effect transistors (FETs) can be compatible with low temperature detection. To reach this goal two key developments are proposed. First, we report gating of nanocrystal films from SrTiO3 used as a ferroelectric material leading to high gate capacitance with leakage and breakdown free operation in the 4-100 K range. Secondly, we demonstrate that this FET is compatible with a plasmonic resonator which role is to achieve strong light absorption from a thin film used as the channel of the FET. Combining three resonances, broad band absorption from 1.5 to 3 µm reaching 30% is demonstrated. Finally combining gate and enhanced light matter coupling, we show that detectivity can be as high as 10 12 jones for a device presenting a 3 µm cutoff wavelength and 30 K operation.
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