Previous research in infrared sensing mainly focused on narrow bandgap semiconductor materials, tunable bandgap two-dimensional (2D) materials. However, it is challenging to integrate them with silicon electronics due to lattice mismatch with silicon. To address this challenge, this work proposes a concept of infrared detection different from that of narrow bandgap semiconductors and 2D materials. In this study, thin metal/semiconductor Schottky devices were fabricated to realize mid-infrared light detection by collecting thermal signals generated by hot carriers with energy lower than the Schottky barrier. Experimental results demonstrate successful detection of mid-infrared light signals at wavelengths of 3.22 μm, 4.28 μm, and 4.83 μm, surpassing the cutoff wavelength corresponding to Schottky barrier. Such Schottky devices exhibit a maximum responsivity of 0.680 mA/W, which confirms their efficiency and application potential in application of mid-infrared optical detection.
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