Room temperature operated short-wave infrared phototransistor optimized via MXene-based metamaterial absorber structure.

Abstract

Recent advances in nanostructured photodetectors have enabled precise control over light absorption while minimizing photon losses. In this work, we demonstrate a plasmonic metamaterial absorber based on two-dimensional MXene (Ti₃C₂Tₓ) featuring geometrically tunable tetragram-shaped arrays. Through finite-difference time-domain (FDTD) simulations and structural optimization, we achieved over 90% photon absorption across the broadband spectral range of 1000-2500 nm, representing a significant enhancement in operational bandwidth. By incorporating HgTe quantum dots (QDs) as an intermediate spacer layer, we developed a hybrid plasmonic-QD phototransistor that leverages gap surface plasmon resonance effects to enhance low-energy photon absorption. This configuration resulted in substantial improvements in current density and achieved a detectivity of 1.46 × 10¹¹ Jones at room temperature. Our findings demonstrate a scalable platform for high-sensitivity broadband photodetection with promising applications in advanced optical sensing systems.