Microwave treatment in 2D-layered molybdenum diselenide (MoSe2) nanoflakes effectively changed structural, optical and charge transport characteristics at the nanoscale level due to the formation of MoO3-MoSe2 dual-phase. The co-existing MoO3-MoSe2 dual-phase, enabled by microwave treatment in pristine MoSe2, was highly sensitive to microwave thermal energy which caused significant shifts in Raman characteristic peaks due to the formation of dual phase which further confirmed in X-ray diffraction. It was also asserted by X-ray photoelectron spectroscopic studies which showed the effects of microwave induced changes on surface chemical characteristics of pristine MoSe2. Specifically, the loosely packed van der Waals sheet-like layers in pristine MoSe2 were engineered by microwave treatment and resulted in platelet-like nanostructures as evidenced in scanning electron microscopic studies. Further, charge transport characteristics in MoSe2 films were examined under dark, AM1.5, blue and green laser illuminations. Microwave treated MoSe2 showed a greater enhancement in photo-response than pristine MoSe2 due to the co-existing MoO3-MoSe2 dual-phase. Thus, microwave treatment can be considered for the development of 2D-optoelectronics as a feasible method to tune the physical properties according to requirements.
A. Vasanth, Shantikumar V Nair, and Dr. Mariyappan Shanmugam, “Microwave Engineered Structural, Nano-morphological and Photo-responsive Characteristics in 2D-layered Dual-phase MoO3-MoSe2 Films”, Applied Surface Science, vol. 519, p. 146263, 2020.