Direct Growth of Al(2)O(3) on Black Phosphorus by Plasma-Enhanced Atomic Layer Deposition

Growing high-quality and uniform dielectric on black phosphorus is challenging since it is easy to react with O(2) or H(2)O in ambient. In this work, we have directly grown Al(2)O(3) on BP using plasma-enhanced atomic layer deposition (PEALD). The surface roughness of BP with covered Al(2)O(3) film can reduce significantly, which is due to the removal of oxidized bubble in BP surface by oxygen plasma. It was also found there is an interfacial layer of PO(x) in between amorphous Al(2)O(3) film and crystallized BP, which is verified by both X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) measurements. By increasing temperature, the PO(x) can be converted into fully oxidized P(2)O(5).