Ferroelectric Gating of Narrow Band-Gap Nanocrystal Arrays with Enhanced Light–Matter Coupling

Abstract

As narrow band gap nanocrystals become a considerable building block for the design of infrared sensors, device design needs to match their actual operating conditions. While in the near and shortwave infrared, room-temperature operation has been demonstrated, longer wavelengths still require low-temperature operations and thus 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 the gating of nanocrystal films from SrTiO3 which leads to high gate capacitance with leakage and breakdown free operation in the 4–100 K range. Second, we demonstrate that this FET is compatible with a plasmonic resonator whose role is to achieve strong light absorption from a thin film used as the channel of the FET. Combining three resonances, broadband 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 1012 Jones for a device presenting a 3 μm cutoff wavelength and 30 K operation.