Triangular structures on tungsten diselenide induced and observed by scanning tunneling microscopy

摘要

By applying voltage pulses of about minus;5 V at the tip of a scanning tunneling microscope triangular structures have been created on the atomically flat WSe2surface. The evolution from a clusterhyphen;like structure directly after the pulse to an equilateral triangle occurs within minutes. The growth of the triangles has been investigated for times up to 1 h. For a given orientation of the substrate all the triangles have the same orientation thereby reducing the sixfold symmetry at the atomic Se surface to the threefold symmetry of a full molecular WSe2layer.