Efficient MoWO/VO/MoS/Si UV Schottky photodetectors; MoS optimization and monoclinic VO surface modifications.

The distinctive properties of strongly correlated oxides provide a variety of possibilities for modulating the properties of 2D transition metal dichalcogenides semiconductors; which represent a new class of superior optical and optoelectronic interfacing semiconductors. We report a novel approach to scaling-up molybdenum disulfide (MoS) by combining the techniques of chemical and physical vapor deposition (CVD and PVD) and interfacing with a thin layer of monoclinic VO. MoWO/VO/MoS photodetectors were manufactured at different sputtering times by depositing molybdenum oxide layers using a PVD technique on p-type silicon substrates followed by a sulphurization process in the CVD chamber. The high quality and the excellent structural and absorption properties of MoWO/VO/MoS/Si with MoS deposited for 60 s enables its use as an efficient UV photodetector. The electronically coupled monoclinic VO layer on MoS/Si causes a redshift and intensive MoS Raman peaks. Interestingly, the incorporation of VO dramatically changes the ratio between A-exciton (ground state exciton) and trion photoluminescence intensities of VO/(30 s)MoS/Si from < 1 to > 1. By increasing the deposition time of MoS from 60 to 180 s, the relative intensity of the B-exciton/A-exciton increases, whereas the lowest ratio at deposition time of 60 s refers to the high quality and low defect densities of the VO/(60 s)MoS/Si structure. Both the VO/(60 s)MoS/Si trion and A-exciton peaks have higher intensities compared with (60 s) MoS/Si structure. The MoWO/VO/(60 s)MoS/Si photodetector displays the highest photocurrent gain of 1.6, 4.32 × 10 Jones detectivity, and ~ 1.0 × 10 quantum efficiency at 365 nm. Moreover, the surface roughness and grains mapping are studied and a low semiconducting-metallic phase transition is observed at ~ 40 °C.