STM-study of triangular defect structures induced on WSe2

With short voltage pulses, applied between sample and tip of a scanning tunnelling microscope, it is possible to generate a variety of defects on the surface of layered transition metal dichalcogenides. In the case of WSe₂ triangular holes can be induced with a depth of a single Se-W-Se layer that grow in lateral size during scanning. We present measurements of the time evolution of the growth and its dependence on parameters of the scanning process. Furthermore, we draw attention to the peculiar shape of the edges of such triangles where several distinct rims are found. As a possible interpretation we suggest that these are caused by an oscillating workfunction or density of states due to electron interference.