PMID- 37812500 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20231025 IS - 1936-086X (Electronic) IS - 1936-0851 (Linking) VI - 17 IP - 20 DP - 2023 Oct 24 TI - Toward High-Performance p-Type Two-Dimensional Field Effect Transistors: Contact Engineering, Scaling, and Doping. PG - 19709-19723 LID - 10.1021/acsnano.3c03060 [doi] AB - n-type field effect transistors (FETs) based on two-dimensional (2D) transition-metal dichalcogenides (TMDs) such as MoS(2) and WS(2) have come close to meeting the requirements set forth in the International Roadmap for Devices and Systems (IRDS). However, p-type 2D FETs are dramatically lagging behind in meeting performance standards. Here, we adopt a three-pronged approach that includes contact engineering, channel length (L(ch)) scaling, and monolayer doping to achieve high performance p-type FETs based on synthetic WSe(2). Using electrical measurements backed by atomistic imaging and rigorous analysis, Pd was identified as the favorable contact metal for WSe(2) owing to better epitaxy, larger grain size, and higher compressive strain, leading to a lower Schottky barrier height. While the ON-state performance of Pd-contacted WSe(2) FETs was improved by approximately 10x by aggressively scaling L(ch) from 1 mum down to approximately 20 nm, ultrascaled FETs were found to be contact limited. To reduce the contact resistance, monolayer tungsten oxyselenide (WO(x)Se(y)) obtained using self-limiting oxidation of bilayer WSe(2) was used as a p-type dopant. This led to approximately 5x improvement in the ON-state performance and approximately 9x reduction in the contact resistance. We were able to achieve a median ON-state current as high as approximately 10 muA/mum for ultrascaled and doped p-type WSe(2) FETs with Pd contacts. We also show the applicability of our monolayer doping strategy to other 2D materials such as MoS(2), MoTe(2), and MoSe(2). FAU - Oberoi, Aaryan AU - Oberoi A AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Han, Ying AU - Han Y AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Stepanoff, Sergei P AU - Stepanoff SP AD - Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, United States. AD - Applied Research Laboratory, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Pannone, Andrew AU - Pannone A AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Sun, Yongwen AU - Sun Y AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Lin, Yu-Chuan AU - Lin YC AD - Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, 1001 University Road, Hsinchu City 300093, Taiwan. FAU - Chen, Chen AU - Chen C AD - 2D Crystal Consortium Materials Innovation Platform, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Shallenberger, Jeffrey R AU - Shallenberger JR AD - Materials Characterization Laboratory, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Zhou, Da AU - Zhou D AUID- ORCID: 0000-0002-7189-5222 AD - Department of Physics, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Terrones, Mauricio AU - Terrones M AUID- ORCID: 0000-0003-0010-2851 AD - Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Physics, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Redwing, Joan M AU - Redwing JM AUID- ORCID: 0000-0002-7906-452X AD - Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, United States. AD - 2D Crystal Consortium Materials Innovation Platform, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Electrical Engineering, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Robinson, Joshua A AU - Robinson JA AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, United States. AD - 2D Crystal Consortium Materials Innovation Platform, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Physics, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Chemistry, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Wolfe, Douglas E AU - Wolfe DE AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, United States. AD - Applied Research Laboratory, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Yang, Yang AU - Yang Y AUID- ORCID: 0000-0002-0025-5914 AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. FAU - Das, Saptarshi AU - Das S AUID- ORCID: 0000-0002-0188-945X AD - Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802, United States. AD - Department of Electrical Engineering, Penn State University, University Park, Pennsylvania 16802, United States. LA - eng PT - Journal Article DEP - 20231009 PL - United States TA - ACS Nano JT - ACS nano JID - 101313589 SB - IM OTO - NOTNLM OT - 2D materials OT - WSe2 OT - p-type doping OT - scaling OT - strain OT - transistors EDAT- 2023/10/09 18:41 MHDA- 2023/10/09 18:42 CRDT- 2023/10/09 12:02 PHST- 2023/10/09 18:42 [medline] PHST- 2023/10/09 18:41 [pubmed] PHST- 2023/10/09 12:02 [entrez] AID - 10.1021/acsnano.3c03060 [doi] PST - ppublish SO - ACS Nano. 2023 Oct 24;17(20):19709-19723. doi: 10.1021/acsnano.3c03060. Epub 2023 Oct 9.