Geng Integrity Report — Vapour–liquid–solid–solid growth of two-dimensional non-layered β-Bi2O3 crystals with high hole mobility (Nature Materials, 2025; DOI: 10.1038/s41563-025-02141-w)

Academic fraud report · Geng Detector

Summary

Verdict: Highly suspicious (orange). Two principal concerns are flagged against the paper, with corroborating but unconfirmed issues remaining. (1) A statistical coincidence is observed between the abstract's claimed peak hole mobility of 136.6 cm² V⁻¹ s⁻¹ and the main text's reported mean ± SD of 130.4 ± 6.2 cm² V⁻¹ s⁻¹ at 2.4 nm thickness, since 136.6 = 130.4 + 6.2 exactly, suggesting the peak value may have been constructed by adding one standard deviation to the mean rather than being independently measured. (2) The authors report direct CVD growth of non-layered β-Bi2O3 (c = 5.634 Å) down to 0.3 nm — a half unit cell — which is thermodynamically anomalous for a non-van-der-Waals 3D covalently bonded oxide, raising doubts that this thickness reflects genuine crystalline material rather than AFM artefacts (substrate contamination, hydration layers). Image-based checks could not be performed on the text-only submission. Submission timeline (received 2 July 2022, accepted 15 January 2025) is internally consistent. Confidence is moderate; no fabricated finding is asserted without further raw-data verification.

Verdict

🟠 Highly suspicious. Two issues of concern are identified, one statistical and one physical, both meriting author response and raw-data disclosure.

Key findings

Statistical coincidence between peak and mean ± SD: The abstract's headline mobility 136.6 cm² V⁻¹ s⁻¹ equals the body-text value 130.4 + 6.2 cm² V⁻¹ s⁻¹ exactly, a "max = mean + 1σ" pattern that is mathematically too clean to be a typical independent measurement.
Thermodynamically anomalous ultrathin limit: Reported CVD growth of non-layered β-Bi2O3 down to 0.3 nm (half the unit cell along c = 5.634 Å) on SiO2/Si is physically unusual for a non-van-der-Waals, 3D-bonded oxide; risk of AFM misidentification of contamination/hydration layers as crystalline film.
Timeline is internally consistent: Received 2 July 2022 → accepted 15 January 2025 → published May 2025 (online 7 March 2025); ~30 months is long but plausible for a Nature Materials revision cycle, and instrumentation (FEI Titan3 G2 60-300, Keysight B1500A, Sigma-Aldrich reagents) is consistent with the submission window.
Image forensics not performed: Only the text PDF was available; no pixel-level reuse, splicing, or PS-trace analysis was possible for Figures 1, 2, or 4.

Evidence highlights

Abstract: peak hole mobility reported as 136.6 cm² V⁻¹ s⁻¹.
Page 694 (FET performance of 2D β-Bi2O3): "average hole mobility of 2D β-Bi2O3 FETs increased … to a maximum of 130.4 ± 6.2 cm² V⁻¹ s⁻¹ at 2.4 nm".
Arithmetic identity: 130.4 + 6.2 = 136.6 (exact).
Synthesis section: minimum thickness 0.3 nm, described by the authors as a half-unit-cell thickness with symmetry breaking; unit cell parameter c = 5.634 Å = 0.5634 nm, so 0.3 nm ≈ c/2.
Reported surface roughness Ra = 0.17 nm (cited as supporting the ultrathin flatness claim).
Timeline: Received 2 July 2022; Accepted 15 January 2025; Published May 2025 (online 7 March 2025).

Notes

The "max = mean + 1σ" coincidence is a red-flag pattern but not proof of fabrication; independent confirmation requires the raw transfer-curve data and the full per-device mobility table.
The 0.3 nm half-unit-cell claim should be cross-checked with cross-sectional HAADF-STEM, thickness mapping across multiple flakes, and AFM phase imaging to rule out adsorbate/hydration artefacts.
Image-level analysis (Figures 1d/e, 2g, 4) is recommended via Forensically/ImageJ on a lossless PDF once obtainable; this report explicitly does not assert image manipulation.
DOI preserved as given: 10.1038/s41563-025-02141-w.
Recommended actions: (a) request per-device raw mobility data and the origin of 136.6; (b) post targeted PubPeer comments on the 136.6 derivation and on the thermodynamic plausibility of a 0.3 nm non-layered oxide; (c) defer journal editorial notification pending author response.