Optothermal and electrical properties of ultrathin alloys of mixed dichalcogenides

Two-dimensional transition metal dichalcogenides are fascinating materials whose properties are tunable with the number of layers and stoichiometry. Ameliorated properties can be realized in ternary and quaternary chalcogenides. Herein, we report composition-tunable optothermal properties of MoS2(1- x)Se2x alloys monolayers (x = 0.25, 0.5 and 0.75) using optothermal Raman spectroscopic method. The temperature and incident laser power-dependent Raman spectroscopic studies of single-layer MoS2(1- x)Se2x alloys yield thermal conductivity value which is found to be maximum for the composition containing the same content of sulfur and selenium (MoS1.0Se1.0) while on either side (S-rich and Se-rich phases), the thermal conductivity decreases. Field effect transistors (FETs) show impressive device characteristics with n-type transport behavior and high on/off current ratio values around 10(8) for MoS2(1- x)Se2x alloy monolayers-based FETs. The mobility values are found to be tunable with composition and the highest value of similar to 40 cm(2) V-1 s(-1) is achieved for a composition containing equal contents of S and Se. FET devices with MoS1.0Se1.0 flakes of different thicknesses reveal transport characteristics that are thickness tunable. The present study provides an insight into the selection of MoSSe, as a suitable composition for electronic device studies. [GRAPHICS] .