Concerns report: 'Vapour–liquid–solid–solid growth of two-dimensional non-layered β-Bi2O3 crystals with high hole mobility' (Nature Materials, 2025)

Academic fraud report · Geng Detector

Summary

Verdict: Questionable (🟡). The report raises four concerns regarding the 2025 Nature Materials article (DOI: 10.1038/s41563-025-02141-w) on 2D β-Bi2O3 growth. (1) The stated elemental composition of the intermediate droplet (40% O, 35% Bi, 15% Cl, 5% Na) sums to 95%, an arithmetic inconsistency that undermines confidence in the underlying EDS/XPS analysis. (2) The main text claims 'no Na/Cl elemental residue' after growth, while the Methods section describes soaking the as-grown sample in 60 °C DI water for 40 min to 'remove residual salt', an internal contradiction. (3) Five CVD-grown non-layered 2D devices show a hole mobility of 130.4 ± 6.2 cm² V⁻¹ s⁻¹ at 2.4 nm thickness, a ~4.7% relative error unusually small for hand-selected 2D oxide FETs and suggestive of cherry-picking. (4) The submission-to-acceptance timeline spans 2 July 2022 to 15 January 2025 (~2.5 years), atypical for the journal and potentially consistent with extended revisions or multiple rejections. No image-level duplication analysis was performed. Confidence is moderate; all findings are text- and arithmetic-based and warrant raw-data verification.

Verdict

Questionable (🟡). Multiple textual, arithmetic, and methodological inconsistencies were identified. No image-level (pixel) duplication analysis was performed; conclusions are limited to logical and statistical scrutiny.

Key findings

Arithmetic inconsistency in elemental composition: 40% O + 35% Bi + 15% Cl + 5% Na = 95%, not 100%; either rounding not disclosed or fabricated values.
Internal contradiction on Na/Cl residue: main text asserts 'no Na/Cl elemental residue'; Methods prescribes a 40 min, 60 °C DI-water soak 'to remove residual salt'.
Implausibly low device-to-device variance: five 2.4 nm-thick devices yield 130.4 ± 6.2 cm² V⁻¹ s⁻¹, a relative error of ~4.7%, atypical for hand-selected CVD-grown 2D non-layered oxide FETs and suggestive of cherry-picking.
Abnormal review timeline: Received 2 July 2022; Accepted 15 January 2025 (~2.5 years), unusual for Nature Materials and consistent with multiple major revisions or transfers.

Evidence highlights

Elemental composition (Page 689): "40% O, 35% Bi, 15% Cl and 5% Na elements" → sum = 95%.
Main text (Page 692): "a pure and monocrystalline 2D β-Bi2O3 crystal and no Na/Cl elemental residue will be obtained on the SiO2/Si substrate."
Methods (Transfer of 2D β-Bi2O3): "the SiO2/Si substrates with 2D β-Bi2O3 were soaked in 60 °C DI water for 40 min to remove residual salt."
Figure 4d / Supplementary Table 2: hole mobility 130.4 ± 6.2 cm² V⁻¹ s⁻¹ at 2.4 nm thickness (n = 5); relative error ≈ 6.2 / 130.4 ≈ 4.8%.
Article header: Received 2 July 2022; Accepted 15 January 2025.
DOI: 10.1038/s41563-025-02141-w.

Notes

All quantitative concerns are derived from text and reported numbers; no pixel-level image analysis was conducted.
The 4.7% device variance is flagged by analogy to typical 2D-material FET variability (commonly 20–50%); a definitive assessment would require raw transfer-curve data and statistics from all measured (not only selected) devices.
The 2.5-year timeline alone is not evidence of misconduct and may reflect normal major-revision cycles; combined with the other findings, it warrants scrutiny.
Recommended follow-up: request original EDS/XPS spectra with quantification settings, raw transfer characteristics for all measured devices, and TEM/EDS evidence of Na/Cl absence on the as-grown crystal surface prior to any rinsing step.
This is an AI-assisted text analysis for academic discussion; formal determination of misconduct requires institutional investigation.