Transformation of MoSe2 to MoSe2-xOy via controlled oxidation for high-performance resistive switching

Abstract

The current study shows an improvised resistive switching in oxygenated MoSe2 (MoSe2-xOy) thin film. 2D nanosheets assembled nanoflower morphology of MoSe2 was synthesized with hydrothermal route and then treated with thermal oxidation process at 300⁰C in presence of 0, 0.5, 5 and 20 % of oxygen. The coexistence of MoSe2 and MoOx in each samples was investigated with various spectroscopic techniques. The conversion to MoOx was maximum in 20 % O2 treated sample while other samples were converted partially. Au/MoSe2-xOy/Au structured devices were fabricated on SiO2/p-Si substrate and tested for resistive switching study. Among all four devices, 5 % O2 treated MoSe2-xOy exhibited excellent filamentary type bipolar resistive switching with very low SET and RESET voltages of + 0.84 V and −0.79 V, respectively. The device showed ION/IOFF ratio ∼50 (at read voltage: 0.5 V) with excellent retention (106 s) and endurance (100 cycles) characteristics with minimum cycle-to-cycle variation. The resistive switching mechanism was explained with valance change conducting filament formation/rupture model and the trap-controlled space charge limited current behavior. Rich transport properties of 2D-chalcogenide (MoSe2) and classic oxygen vacancy migrated switching of metal oxide (i.e. MoOx), were simultaneously important for achieving high performance memristive behavior in 5 % O2 treated MoSe2.