Thin Nanostructured n-WSe2 Films and Their Application in Semiconductor p-Si Photocathodes for Hydrogen Production by Water Splitting

The possibilities of controlling the structure and type of conductivity of WSe2 films formed on p-type silicon by thermal treatment of a thin-film precursor, which was preliminary obtained using pulsed laser deposition, are studied. Pulsed laser ablation of WSe2 and rhenium targets make it possible to obtain amorphous films WSex (x > 2) containing rhenium atoms and inclusions of β-W nanoparticles. During heat treatment at 450°C, the amorphous matrix crystallization occurs, and a layered shell of 2H-WSe2 is formed around the metal nanoparticles. Doping with rhenium leads to the production of n-type WSe2 semiconductor films, which, in terms of their combination of properties (band gap ~1.2 eV, high catalytic activity, and low resistance to current flow), represent a promising material for creating p-Si photocathodes for efficient light-activated production of hydrogen in an acid solution. Theoretical calculations are carried out, which make it possible to identify local areas of the surface of the formed WSe2 films with enhanced catalytic activity in the reaction of hydrogen evolution.