Figure 5.

Sublimation of Mo oxide layers. (A) shows an initial MoS₂ flake obtained by AFM imaging in non-contact mode. (B) presents additional build-ups, likely MoO₃ layers, deposited on various portions of the flake after its short oxidation at 370 °C followed by one month stay in humid desiccator. A marked cross-sectional line (in red) shows that a typical thickness of an oxide layer is ca. 5 nm. Inset: corresponding AFM phase imaging, which seems to differentiate roughly oxidized (white) vs. non-oxidized (gray) portions of the flake, at least on a top part of the flake. (C) shows that the entire oxide layer sublimated after the sample was heated at 320 °C for only 4 minutes. Z-scale in (A) was 132 nm, in (B) 129 nm and in (C) 90 nm.