Unveiling Composition-Properties Relationships in Mo1-xWxSe2 Alloys: A Theoretical and Experimental Study.

Two-dimensional transition metal dichalcogenide (TMD) alloys have emerged as a versatile platform for electronic, optoelectronic, and quantum applications due to their tunable crystal structure and unique electronic properties. In this study, we investigate the influence of atomic composition on the structural, electronic, and optical properties of the Mo1-xWxSe2 alloy, combining experimental and theoretical approaches. Samples with different Mo and W ratios were synthesized and characterized using Raman and photoluminescence (PL) spectroscopies, and atomic force microscopy (AFM). Local anodic oxidation (LAO) was employed to manipulate monolayers within the alloy flakes, revealing significant luminescence enhancement in the engineered islands, suggesting structural and electronic modifications. Additionally, density functional theory (DFT) calculations indicated that oxidation stability strongly depends on atomic composition, with the Mo0.5W0.5Se2 and Mo0.75W0.25Se2 alloys exhibiting the highest resistance to vacancy formation. These findings highlight the potential for structural and electronic engineering of Mo1-xWxSe2 alloys, paving the way for advanced applications in nanotechnology and quantum computing.