High-Performance Lossy-Mode Resonance Sensor Based on Few-Layer Black Phosphorus

Surface plasmon resonance (SPR) can be excited only by the transverse magnetic (TM)-polarized light in the conventional SPR sensor, whereas the lossy-mode resonance (LMR) can be achieved with both transverse electric (TE)- and TM-polarized lights. In this work, we propose a high-performance LMR sensor based on few-layer black phosphorus (BP), and the high quality factor (<i>Q</i>) of this BP-based LMR sensor for TE- and TM-polarized lights has been discussed. In comparison with that for the conventional SPR sensor, the <i>Q</i> factor for the proposed BP-based LMR sensor with both TE- and TM-polarized lights has been greatly improved. In particular, the highest <i>Q</i> factor as high as 2 × 10⁵ RIU^–1 can be obtained for the TM-polarized mode

Fabry–Perot Cavity-Enhanced Optical Absorption in Ultrasensitive Tunable Photodiodes Based on Hybrid 2D Materials

Monolayer two-dimensional (2D) transition metal dichalcogenides (TMDs) show interesting optical and electrical properties because of their direct bandgap. However, the low absorption of atomically thin TMDs limits their applications. Here, we report enhanced absorption and optoelectronic properties of monolayer molybdenum disulfide (MoS₂) by using an asymmetric Fabry–Perot cavity. The cavity is based on a hybrid structure of MoS₂/ hexagonal boron nitride (BN)/Au/SiO₂ realized through layer-by-layer vertical stacking. Photoluminescence (PL) intensity of monolayer MoS₂ is enhanced over 2 orders of magnitude. Theoretical calculations show that the strong absorption of MoS₂ comes from photonic localization on the top of the microcavity at optimal BN spacer thickness. The n/n⁺ MoS₂ homojunction photodiode incorporating this asymmetric Fabry–Perot cavity exhibits excellent current rectifying behavior with an ideality factor of 1 and an ultrasensitive and gate-tunable external photo gain and specific detectivity. Our work offers an effective method to achieve uniform enhanced light absorption by monolayer TMDs, which has promising applications for highly sensitive optoelectronic devices