Area-Selective MOCVD Synthesis of VO2(B) and VO2(M) Phases on a Si Substrate

Vanadium dioxide (VO
2
) has a wide range of physical properties due to the existence of polymorphs. The most interesting ones for practical applications are the M- and B- phases of VO
2
. The M-phase exhibits a reversible structural and ultrafast (26 fs) electronic semiconductor-metal phase transition, and the B-phase offers a promising semimetal for electronics. For controlling the properties of VO
2
, it is important to be able to selectively synthesize structures containing a given phase of the deposited material. In the present study, the possibility of area-selective synthesis of VO
2
films with M- and B-phases on silicon substrates was discovered for the first time. It was found that only the B-phase grew on the substrate area treated with polyvinyl alcohol (PVA), and only the M-phase of VO
2
was synthesized on the initial (virgin) surface of the substrate. The dependence of the morphology of the VO
2
films on the thickness of the PVA layer was revealed. The ability to control the growth of various phases of polymorphic materials under identical synthesis conditions opens up prospects for the formation of laterally arranged heterostructures with new functional properties.