Atomic and electronic structure of two-dimensional Mo_(1? _x )W _x S₂ alloys

Abstract Alloying enables engineering of the electronic structure semiconductors for optoelectronic applications. Due to their similar lattice parameters, two-dimensional semiconducting transition metal dichalcogenides MoWSeS group (MX 2 where M = Mo or W and X S Se) can be grown as high-quality materials with low defect concentrations. Here we investigate atomic (1? x ) alloys using a combination high-resolution experimental techniques simulations. Analysis positions in these alloys, by chemical vapour transport, shows that they are randomly distributed, consistent Monte Carlo simulations use interaction energies determined from first-principles calculations. Electronic parameters directly angle resolved photoemission spectroscopy measurements. These show spin–orbit splitting at valence band edge increases linearly content MoS WS , agreement linear-scaling density functional theory predictions. The conduction is predicted reduce zero intermediate compositions. Despite this, polarisation-resolved photoluminescence spectra on monolayer 0.5 significant circular dichroism, indicating spin-valley locking retained. results demonstrate alloying an important tool controlling MX spintronic valleytronic