Lundi 23 mai 2022 à 11 h.
Kaycee Underwood – Université de St. Andrews
NbSe2 is one of the broad family of transition-metal dichalcogenides (TMD). With this work we investigated the growth dynamics of monolayer TMD films grown via molecular beam epitaxy and determined three growth regimes; dendritic, fractal and compact. Through atomic force microscopy of the films, grown under a variety of conditions, this work identifies that a high adatom mobility and a slower growth rate are required to stabilise the preferred compact growth regime. With this information we investigate the polymorph control of monolayer NbSe2 which is found to grow in the 1T and 1H polymorph which display insulating and metallic properties respectively. Our results suggest that island area determines the resulting polymorph with smaller islands leading to preferential growth of the 1T polymorph and larger islands the 1H polymorph.