ELECTRICAL-FIELD INDUCED GROWTH OF TRIANGULAR NANOMETER STRUCTURES ONWSE2

We report on the conditions for the growth of triangular structures on WSe2 surfaces in scanning tunneling experiments with a vertical dimen sion of one layer (Se-W-Se) and up to 200 nm in horizontal direction. Experiments carried out in different atmospheres (ambient air, dry N-2 , dry O-2) suggest that the growth is directly related to the presence of a thin physisorbed water layer on the surface of WSe2. Furthermore examinations under different scanning and bias conditions show that t he electric field of the tip induces the growth of these nanometer str uctures.