LAYER-BY-LAYER NANOMETER SCALE ETCHING OF 2-DIMENSIONAL SUBSTRATES USING THE SCANNING TUNNELING MICROSCOPE

The scanning tunneling microscope can be used to sequentially etch single molecular layers from the surface of two-dimensional materials (i.e., SnSe2, TiSe2, and NbSe2). Etching occurs by the nucleation and growth of holes in the region of the sample rastered by the tip under normal conditions of tunneling bias and current. In the case of etching NbSe2, triangular etch pits are formed in the initial etching stages. The mechanism for the etching process is unknown at this point although four reasonable mechanisms are proposed. Several submicron complex structures have been prepared as well as a structure as small as 25 ⨯ 25 ⨯ 1.2 nm. © 1990, American Chemical Society. All rights reserved.