Fig. 2: Ab initio molecular dynamics (AIMD) simulations of HfSe2 and HfSe2/TMD (HfSe2, MoS2, and WSe2) interface oxidations. | Nature Communications

Fig. 2: Ab initio molecular dynamics (AIMD) simulations of HfSe2 and HfSe2/TMD (HfSe2, MoS2, and WSe2) interface oxidations.

From: High-κ dielectric van der Waals integration on 2D semiconductors for three-dimensional complementary logic systems

Fig. 2: Ab initio molecular dynamics (AIMD) simulations of HfSe2 and HfSe2/TMD (HfSe2, MoS2, and WSe2) interface oxidations.

a A sequence of microcanonical (NVE) and canonical ensemble (NVT) dynamics (highlighted by the light green box) is performed to simulate the oxidation of a monolayer HfSe2. Oxygen atoms are inserted at the start of NVE dynamics (red box), followed by NVT dynamics (blue box) after the removal of floating Se atoms. The striped arrow represents repeated application of the NVE–NVT cycle. b A partially oxidised HfSe2 (O36 model)/pristine HfSe2 structure undergoes further oxidation under the same NVE–NVT scheme, resulting in layer-by-layer oxidation and retention of a vdW gap. c A comparative analysis of O36 model/TMD interfaces within a single NVE dynamics step, where oxygen atoms are directed toward the bottom TMD layer. In HfSe2 (top), oxidation proceeds at the bottom layer, while in MoS2 (middle) and WSe2 (bottom), oxygen atoms primarily passivate the bottom surface of the upper oxide layer.

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