Speakers - 2026

Title: Enhanced photodetection in intermixed TMD nanodiscs graphene heterostructure nanohybrids

Abstract

Nanohybrids based on van der Waals (vdW) heterostructures of 2D atomic materials have recently emerged as a unique scheme for designing high-performance quantum sensors. This work explores vdW nanohybrids for photodetection, which consist of graphene decorated with intermingled transition-metal dichalcogenide (TMDC) nanodiscs (TMDC-NDs) obtained using wafer-size, layer-by-layer growth. The obtained TMDC-NDs/graphene nanohybrids take advantages of a strong quantum confinement in graphene for high charge mobility and hence high photoconductive gain, and localized surface plasmonic resonance (LSPR) enabled on the TMDCNDs for enhanced light absorption. Since the LSPR depends on the nanostructure's size and density, intermingled TMDC-NDs of different kinds of TMDCs, such as WS2 (W) and MoS2 (M), have been found to allow small-size, high concentration TMDC-NDs to be achieved for high photoresponse. Remarkably, high photoresponsivity up to 31 A/W (550 nm wavelength and 20 W/cm2 light intensity) has been obtained on the WMW-NDs/graphene nanohybrids photodetectors made using three consecutive coatings of WS2 (1st and 3rd coating) and MoS2 (2nd coating), which is considerably higher by a factor of ~4 than that of the counterparts MoS2- ND/graphene or WS2-NDs/graphene devices. This result provides a facile approach to control the size and concentration of the TMDC-NDs for high-performance, low-cost optoelectronic device applications.