PREPARATION OF WSE2 SURFACES WITH HIGH PHOTOACTIVITY

Layered dichalcogenide semiconductors (LS) are studied intensively for photovoltaic applications. It is generally accepted that the smooth van der Waals face (perpendicular-to c) is most suitable for this purpose. Recombination centers have been associated with surface steps (exposing parallel-to c facets) or near-surface dislocations. Efforts to passivate the recombination centers had, until now, only limited success. In contrast to this approach, a method of surface preparation of LS, leading to rough surfaces that exhibit high photoactivity with high reproducibility, is presented. The physical principles underlying this technique are discussed in detail.