Microscopic growth mechanism and edge states of monolayer 1T'-MoTe2

Abstract

Transition metal ditellurides (TMTDs) have versatile physical properties, including non-trivial topology, Weyl semimetal states and unique spin texture. Controlled growth of high-quality and large-scale monolayer TMTDs with preferred crystal phases is crucial for their applications. Here, we demonstrate the epitaxial growth of 1T'-MoTe2 on Au (111) and graphitized silicon carbide (Gr/SiC) by molecular beam epitaxy (MBE). We investigated the morphology of the grown 1T'-MoTe2 at the atomic level by scanning tunnelling microscopy (STM) and revealed the corresponding microscopic growth mechanism. We found that the unique ordered Te structures preferentially deposited on Au (111) regulated the growth of monolayer single crystal 1T'-MoTe2, while the Mo nucleation sites deposited on Gr/SiC substrate firstly instead of Te structures impeded the ordered growth of monolayer MoTe2. We confirm that the size of single crystal 1T'-MoTe2 grown on Au (111) is nearly two orders of magnitude larger than that on Gr/SiC. By scanning tunnelling spectroscopy (STS), We observe that the STS spectrum of the monolayer 1T'-MoTe2 nano-island at the edge is different from that at the interior, which exhibits enhanced conductivity.