On the importance of safe practices of mobility evaluation in field-effect transistor and Hall effect measurements of novel materials.

This is a pre-review version of a Matters Arising article written in connection with A. Liu, H. Zhu, S. Bai, Y. Reo, T. Zou, M.-G. Kim, Y.-Y. Noh, "High-performance inorganic metal halide perovskite transistors", Nat. Electron. 5, 78-83 (2022). This Matters Arising shows that the main conclusions of this paper are not supported by the experimental data. In brief, it appears that the charge carrier mobility of the investigated perovskite FETs was extracted incorrectly, and the correct estimates yield much lower values. In addition, replotting the authors' original data on double-linear plots reveals a large hysteresis, significant nonlinearities and noise, showing that the main message of the paper (achieving "high-performance" perovskite transistors) is misleading. Furthermore, we have discovered a huge (three orders of magnitude) inconsistency between the Hall and FET measurements in this paper, strongly suggesting that the Hall measurements are faulty. This Matters Arising can serve as a reminder of the importance of save practices of mobility extraction in FETs and Hall effect measurements of novel materials.* 

*DISCLAIMER: 

This Report is 100% based on the publicly verifiable information, including data, claims, and conclusions published in the paper being commented on, as well as some well-known scientific texts on the subject (textbooks, book chapters, or papers published in peer-review journals). The discussion in this Report is 100% focused on the facts and the science. All concerns expressed in this Report are a factual description and analysis of the published work, presented in a factual manner. The truthfulness and meaningfulness of each comment of this Report can be verified by independent experts in the relevant fields (solid-state and materials physics, semiconductor electronics, semiconductor physics, physics of semiconductor devices, and, specifically, field-effect transistors). Each comment of the Report is fully supported by the careful and detailed analysis of the published data and claims. The Report does not contain any allegations of misconduct, fraud, or any other wrongdoing by the authors. The Report does not contain any personal comments about the authors or any other speculations regarding their actions, motives, intentions, level of intelligence, level of expertise, social or academic statue, or their state of mind.