Van der Waals Coupled Organic Molecules with Monolayer MoS₂ for Fast Response Photodetectors with Gate-Tunable Responsivity

Abstract

As a direct-band-gap transition metal dichalcogenide (TMD), atomic thin MoS has attracted extensive attention in photodetection, whereas the hitherto unsolved persistent photoconductance (PPC) from the ungoverned charge trapping in devices has severely hindered their employment. Herein, we demonstrate the realization of ultrafast photoresponse dynamics in monolayer MoS by exploiting a charge transfer interface based on surface-assembled zinc phthalocyanine (ZnPc) molecules. The formed MoS/ZnPc van der Waals interface is found to favorably suppress the PPC phenomenon in MoS by instantly separating photogenerated holes toward the ZnPc molecules, away from the traps in MoS and the dielectric interface. The derived MoS detector then exhibits significantly improved photoresponse speed by more than 3 orders (from over 20 s to less than 8 ms for the decay) and a high responsivity of 430 A/W after AlO passivation. It is also demonstrated that the device could be further tailored to be 2-10-fold more sensitive without severely sacrificing the ultrafast response dynamics using gate modulation. The strategy presented here based on surface-assembled organic molecules may thus pave the way for realizing high-performance TMD-based photodetection with ultrafast speed and high sensitivity.

The influence of two-dimensional organic adlayer thickness on the ultralow frequency Raman spectra of transition metal dichalcogenide nanosheets

“…Two-dimensional (2D) materials have quite large surface to volume ratio and thus their properties are inevitably affected by various physisorbed adsorbates on their top surface at ambient condition [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. For instance, the adsorbed hydrogen atoms were demonstrated to open the zero bandgap of graphene [1].…”

Design of Single‐Molecule Multiferroics for Efficient Ultrahigh‐Density Nonvolatile Memories

“…[30] In any case, the intercalated MP may bind to one S atom of either layer such that a vertical polarization can be produced. Note that similar coupled MP-MoS 2 systems have already been experimentally explored as photodetectors.…”

Design strategies for two‐dimensional material photodetectors to enhance device performance

“…Over the years, great progress has been made in organic photodetectors with the promotion of organic solar cells (OSCs), which is applied to many aspects . Incorporating 2D materials with organic materials to design large‐area scalability, tunable, high responsivity device due to the prominent properties of organic semiconductor . Jariwala et al fabricated a MoS 2 /pentacene vdW p‐n photodetector (shown in Figure A), with a remarkable performance.…”