Surface structures of tellurium on Si(111)-(7 x 7) studied by low-energy electron diffraction and scanning tunneling microscopy
Abstract
The Te-covered Si(111) surface has received recent interest as a template for the epitaxy of van der Waals (vdW) materials, e.g. Bi2Te3.
Here, we report the formation of a Te buffer layer on Si(111)-(7 x 7) by low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). While deposition of several monolayer (ML) of Te on the Si(111)-(7 x 7) surface at room temperature results in an amorphous Te layer, increasing the substrate temperature to 770 K results in a weak (7 x 7) electron diffraction pattern.
Scanning tunneling microscopy of this surface shows remaining corner holes from the Si(111)-(7 x 7) surface reconstruction and clusters in the faulted and unfaulted halves of the (7 x 7) unit cells. Increasing the substrate temperature further to 920 K leads to a Te/Si(111)-(2 root 3 x 2 root 3)R30 degrees surface reconstruction.
We find that this surface configuration has an atomically fiat structure with threefold symmetry.