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High-mobility van der Waals ambipolar semiconductors are promising in logic and reconfigurable circuits, integrated optoelectronic circuits, due to the excellent gate-controlled capability and effectively tunability of major charge carriers by electrostatic field. Controllable growth of high-quality ambipolar semiconductors with high mobility and stability is highly glamorous and indispensable for further research. Here, we demonstrate a straightforward space-confined chemical vapor deposition (CVD) method to synthesize high-quality quasi-one-dimensional (1D) tellurium (Te) nanoribbons (NRs). By introducing H2 into the gas flow, endothermic compound H2Te was generated from the reaction of liquid Te with H2, and consequently decomposed into elemental Te at low temperature. Further, the Te NRs have been utilized for in-situ fabrication of field-effect transistors (FETs) without transferring process. Ambipolar features are achieved using nickel (Ni) as an ohmic contact. More importantly, the mobilities of the Te NR transistor for hole/electron are as high as 1755/28.6 cm2V−1s−1 and 4024/278 cm2V−1s−1 at room temperature and under a temperature below 20 K, respectively. Our findings confirm the novel strategy for synthesizing 1D elemental semiconductors and their applications with ambipolar behaviors. Agency for Science, Technology and Research (A*STAR) National Research Foundation (NRF) Submitted/Accepted version The authors gratefully acknowledge financial support by National Key Research and Development Program of China (2020YFB2008501), the National Natural Science Foundation of China (61974120 and 11904289), Key Research and Development Program of Shaanxi Province (2020ZDLGY04-08, 2020GXLH-Z-027, and 2021JZ-43), the Natural Science Foundation of Shaanxi Province (2023-JC-YB-495 and 2022JQ-659), the Key Program for International Science and Technology Cooperation Projects of Shaanxi Province (2018KWZ-08), the Natural Science Foundation of Ningbo (202003N4003), the Fundamental Research Funds for the Central Universities (3102019PY004, 31020190QD010, and 3102019JC004), the start-up funds from Northwestern Polytechnical University, and open research fund of the State Key Laboratory of Organic Electronics and Information Displays. This work was also supported by National Research Foundation–Competitive Research Program NRF-CRP22-2019-0007 and NRF-CRP21-2018-0007, and supported by A*STAR under its AME IRG Grant (Project No. A2083c0052).

Rational design of noble metal catalysts with the potential to leverage efficiency is vital for industrial applications. Such an ultimate atom-utilization efficiency can be achieved when all noble metal atoms exclusively contribute to catalysis. Here, we demonstrate the fabrication of a wafer-size amorphous PtSe film on a SiO substate via a low-temperature amorphization strategy, which offers single-atom-layer Pt catalysts with high atom-utilization efficiency (~26 wt%). This amorphous PtSe (1.2 < x < 1.3) behaves as a fully activated surface, accessible to catalytic reactions, and features a nearly 100% current density relative to a pure Pt surface and reliable production of sustained high-flux hydrogen over a 2 inch wafer as a proof-of-concept. Furthermore, an electrolyser is demonstrated to generate a high current density of 1,000 mA cm. Such an amorphization strategy is potentially extendable to other noble metals, including the Pd, Ir, Os, Rh and Ru elements, demonstrating the universality of single-atom-layer catalysts. [Figure not available: see fulltext.], This work was supported by the Singapore National Research Foundation Singapore programme (NRF-CRP21-2018-0007, NRF-CRP22-2019-0060, NRF-CRP18-2017-02 and NRF–CRP19–2017–01) and the Singapore Ministry of Education via AcRF Tier 3 (MOE2018-T3-1-002), AcRF Tier 2 (MOE2017-T2-2-136, MOE2019-T2-2-105 and MOE2018-T2-1-176) and AcRF Tier 1 (RG7/18 and 2019-T1-002-034). It was also supported by the National Key Research and Development Program of China (2019YFA0705400, 2021YFE0194200), the National Natural Science Foundation of China (11772153, 22073048, 21763024, 22175203, 22006023), the Natural Science Foundation of Jiangsu Province (BK20190018), the National Key R&D Program of China (2021YFA1500900), the Fundamental Research Funds for Central Universities (531119200209, NE2018002, NJ2020003) and the High-Performance Computing Center of Nanjing Tech University. Catalan Institute of Nanoscience and Nanotechnology (ICN2) acknowledges funding from Generalitat de Catalunya 2017SGR327 and the project NANOGEN (PID2020-116093RB-C43), funded by MCIN/AEI/10.13039/501100011033/. ICN2 is supported by the Severo Ochoa programme from Spanish MINECO (grant no. SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 823717-ESTEEM3.

Reducing the lateral scale of two-dimensional (2D) materials to one-dimensional (1D) has attracted substantial research interest not only to achieve competitive electronic applications but also for the exploration of fundamental physical properties. Controllable synthesis of high-quality 1D nanoribbons (NRs) is thus highly desirable and essential for further study. Here, we report the implementation of supervised machine learning (ML) for the chemical vapor deposition (CVD) synthesis of high-quality quasi-1D few-layered WTe2 NRs. Feature importance analysis indicates that H2 gas flow rate has a profound influence on the formation of WTe2, and the source ratio governs the sample morphology. Notably, the growth mechanism of 1T' few-layered WTe2 NRs is further proposed, which provides new insights for the growth of intriguing 2D and 1D tellurides and may inspire the growth strategies for other 1D nanostructures. Our findings suggest the effectiveness and capability of ML in guiding the synthesis of 1D nanostructures, opening up new opportunities for intelligent materials development. Ministry of Education (MOE) The authors gratefully acknowledge financial support by National Key Research and Development Program of China (2020YFB2008501 and 2019YFC1520900), the National Natural Science Foundation of China (61974120, 11904289, 61701402, and 61804125), Key Research and Development Program of Shaanxi Province (2020ZDLGY04-08, 2020GXLH-Z-027, 2021JZ-43), the Key Program for International Science and Technology Cooperation Projects of Shaanxi Province (2018KWZ-08), the Natural Science Foundation of Shaanxi Province (2019JQ-613), the Natural Science Foundation of Ningbo (202003N4003), the Fundamental Research Funds for the Central Universities (3102019PY004, 31020190QD010, and 3102019JC004), and the start-up funds from Northwestern Polytechnical University. The authors also acknowledge the support from Ministry of Education, Singapore, under its AcRF Tier 3 Programme "Geometrical Quantum Materials" (MOE2018-T3-1-002) and AcRF Tier 1 RG161/19.