Growth kinetics and atomistic mechanisms of native oxidation of ZrSₓSe₂₋ₓ and MoS₂ crystals
Summary¶
This entry registers an alternate corpus PDF path (papers/Others/Jo_MoS2_ZrS2_oxidation_acs.nano_2020.pdf) for the Nano Letters article DOI 10.1021/acs.nanolett.0c03263. Spectroscopic ellipsometry follows native oxide growth on cleaved bulk ZrSₓSe₂₋ₓ alloys vs MoS₂; ReaxFF reactive MD (with first-principles checks summarized in the Supporting Information) interprets O₂ chemisorption, Zr–O network formation, chalcogen redox, and late-stage SO₂ evolution. Zr-based alloys oxidize rapidly in air with rate increasing in Se content, whereas MoS₂ basal surfaces stay essentially non-reactive on laboratory timescales under the reported conditions. Canonical full write-up: [[2020seong-soon-jo-nano-lett-0-nl0c03263]]. The comparative Zr vs Mo storyline highlights early-stage oxygen uptake as metal–chalcogen chemistry-controlled: Zr oxides form readily from cleaved surfaces, while MoS₂ basal planes present unfavorable O₂ activation in both experiment and simulation.
Methods¶
Experiments: ambient oxidation of cleaved crystals; ellipsometry for sub-nm oxide thickness evolution (see article). Atomistics: ReaxFF for Mo/Zr/S/O with development and benchmarks in SI; reactive MD at representative temperatures (including 800 K short runs and 1500 K longer runs for SO₂ egress in the main text). Validation: authors reference first-principles QMD comparisons for key ZrS₂ oxidation steps (SI). File-specific note: two PDFs share one DOI—use primary page for figure/table alignment if paths differ.
Trajectory analysis: authors monitor oxide thickness proxies, gas species counts, and chalcogen oxidation state evolution to connect ellipsometry slopes to elementary steps in MD.
MD application (ReaxFF). ReaxFF reactive molecular dynamics on 3D PBC TMD slabs (full atom counts in pdf_path and SI); ~800 K vs ~1500 K stages with ps–ns total durations as on [[2020seong-soon-jo-nano-lett-0-nl0c03263]]. Timestep: N/A — femtosecond-scale integrator settings are not duplicated in this duplicate-path note; read pdf_path. Ensemble: NVT-style thermostated ramped-T windows in the published text. Pressure in MD: N/A — 1 bar-scale ambient (ellipsometry) vs O₂ (MD); see pdf_path. This file is a duplicate corpus path for the same DOI; reproduce all settings from pdf_path. Barostat: N/A — Electric field: N/A — Umbrella / replica: N/A — as on the primary sibling page above.
Findings¶
ZrSₓSe₂₋ₓ oxidation begins with favorable O₂ adsorption, Zr–O bond switching and vdW gap collapse, and successive chalcogen redox; SO₂ formation/egress is the slow step in the mechanism narrative, with 1500 K simulations showing SO₂ escape where 800 K runs are too short. MoS₂ shows unfavorable basal O₂ chemisorption in the model, consistent with slow oxidation in experiment. Numbers and trajectory discussion: [[2020seong-soon-jo-nano-lett-0-nl0c03263]].
Alloy trend: increasing Se content in ZrSₓSe₂₋ₓ correlates with faster ambient oxidation in ellipsometry, interpreted via weaker metal–chalcogen bonding and favorable O incorporation pathways relative to sulfide-rich compositions.
Corpus honesty: canonical protocol narrative and figure-pointed repro steps are on [[2020seong-soon-jo-nano-lett-0-nl0c03263]] with papers/ReaxFF_others/Jo_Sungwook_acs.nanolett_2020_ZrSSe_MoS2.pdf. This pdf_path is an alternate duplicate of the same DOI only.
Limitations¶
High-temperature MD accelerates chemistry; mapping to room-temperature kinetics requires care. Two corpus PDFs for one DOI—prefer consistent citation to one file for locators. Ambient ellipsometry rates also depend on humidity, defect density, and edge exposure not fully encoded in ideal basal slab models. Plasma enhanced CVD impurities may introduce catalytic oxidation pathways beyond those captured in pristine surface models.
Relevance to group¶
ReaxFF_others corpus reference; no van Duin authorship—comparative context for TMD oxidation.