(AGENPARL) – LONDON (UNITED KINGDOM), ven 18 settembre 2020
The surfaces of some IIB-VI semiconductors (ZnX, X=O, S, Se) were metallized by neighboring highly polar and atomically vertically aligned (VA) liquid crystal (LC) molecules. Due to polar catastrophe, the charge carriers swarmed in an extremely thin layer and the density can achieve at 4.86×1028 m-3 near the LC layer, which can be regarded as 2-dimensional electron gas (2DEG). The modified layer dielectric functions fall into negative in the visible region from density function theory (DFT). This marks the semiconductor/LC platform as ideal active plasmonic candidate, apart from lossy metal constituents. Experimentally, mediated with the phase gratings written in the LC system, surface plasmon polaritons (SPPs) can be excited at the semiconductor surface and localized charges are gathered in adjacent LC layer. With the help of enhanced static electric field by metallic surface, much more 2D diffraction orders in many rows and columns and huge energy transferring between laser beams and SPPs were observed, which consistent nicely with the metallization picture and bidirectional coupling between SPPs and incident lights. The generalization of II-VI semiconductors makes the system very promising in practical applications owing to ultra-low loss. The new insight regarding this combination with LC will be beneficial to the real-time holographic display and tunable epsilon near zero points studying.
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