Formation of monolayer V5Se8 from multilayer VSe2 films via V- and Se-desorption

Two-dimensional van derWaals vanadium selenide compounds are expected to be a key platform for searching the new emergent phenomena by forming the artificial heterostructures. Here, we systematically investigated the electronic properties of monolayer and multilayer vanadium selenide films grown with different conditions using in situ angle-resolved photoemission spectroscopy and first-principles calculations. We observed the band dispersions of pristine VSe2 in a sample grown at substrate temperature (T-sub) of 250 degrees C, whereas the significant modulations of the Se-derived bands can be seen at T-sub = 380 degrees C. For T-sub = 420 degrees C, we found that the V self-intercalated V5Se8 was formed. As a simple and convenient way, we also demonstrate that the monolayer V5Se8 can be fabricated by annealing from the multilayer VSe2 film, and the possible formation mechanism is discussed. The establishment of the growth methods of the V5Se8 film and verifying its electronic properties provide the substantial step for the creation of the two-dimensional van der Waals heterostructures.

Automated summary

We systematically investigated the electronic properties of two-dimensional van der Waals vanadium selenide films grown under different conditions. The results revealed the importance of growth temperature and provided insights into the formation mechanism of the films.