{"title":"Low-resistivity Ohmic contacts of Ti/Al on few-layered 1T’-MoTe2/2H-MoTe2 heterojunction grown by chemical vapor deposition","authors":"Ping Fing Chi, Jing-Jie Wang, Jing-Wen Zhang, Yung-Lan Chuang, Ming-Lun Lee, Jinn-Kong Sheu","doi":"10.1039/d4nh00347k","DOIUrl":null,"url":null,"abstract":"This study explores the phase-controlled growth of few-layered 2H-MoTe<small><sub>2</sub></small>, 1T’-MoTe<small><sub>2</sub></small>, and 2H-/1T’-MoTe<small><sub>2</sub></small> heterostructures and their impacts on metal contact properties. Cold-wall chemical vapor deposition (CW-CVD) with varying growth rates of MoOx and reaction temperatures with Te vapors enabled the growth of continuous thin films of either 1T’-MoTe2 or 2H-MoTe2 phases on two-inch sapphire substrates. This methodology facilitates the meticulous optimization of chemical vapor deposition (CVD) parameters, enabling the realization of phase-controlled growth of few-layered MoTe2 thin films and their subsequent heterostructures. The study further investigates the influence of a 1T’-MoTe<small><sub>2</sub></small> intermediate layer on the electrical properties of metal contacts on few-layered 2H-MoTe<small><sub>2</sub></small>. Bi-layer Ti/Al contacts directly deposited on 2H-MoTe<small><sub>2</sub></small> exhibited a Schottky behavior, indicating inefficient carrier transport. However, introducing a few-layered 1T’-MoTe2 intermediate layer between the metal and 2H-MoTe2 layers improved the contact characteristics significantly. The resulting Al/Ti/1T’-MoTe<small><sub>2</sub></small>/2H-MoTe<small><sub>2</sub></small> contact scheme demonstrates Ohmic behavior with a specific contact resistance of around 1.7x10<small><sup>-4</sup></small> Ω-cm<small><sup>2</sup></small>. This substantial improvement is attributed to the high carrier concentration of the 1T’-MoTe<small><sub>2</sub></small> intermediate layer, facilitating increased tunneling events across the van der Waals gap and enhancing carrier transport between the metal and 2H-MoTe<small><sub>2</sub></small>.","PeriodicalId":93,"journal":{"name":"Nanoscale Horizons","volume":null,"pages":null},"PeriodicalIF":8.0000,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nanoscale Horizons","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1039/d4nh00347k","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
This study explores the phase-controlled growth of few-layered 2H-MoTe2, 1T’-MoTe2, and 2H-/1T’-MoTe2 heterostructures and their impacts on metal contact properties. Cold-wall chemical vapor deposition (CW-CVD) with varying growth rates of MoOx and reaction temperatures with Te vapors enabled the growth of continuous thin films of either 1T’-MoTe2 or 2H-MoTe2 phases on two-inch sapphire substrates. This methodology facilitates the meticulous optimization of chemical vapor deposition (CVD) parameters, enabling the realization of phase-controlled growth of few-layered MoTe2 thin films and their subsequent heterostructures. The study further investigates the influence of a 1T’-MoTe2 intermediate layer on the electrical properties of metal contacts on few-layered 2H-MoTe2. Bi-layer Ti/Al contacts directly deposited on 2H-MoTe2 exhibited a Schottky behavior, indicating inefficient carrier transport. However, introducing a few-layered 1T’-MoTe2 intermediate layer between the metal and 2H-MoTe2 layers improved the contact characteristics significantly. The resulting Al/Ti/1T’-MoTe2/2H-MoTe2 contact scheme demonstrates Ohmic behavior with a specific contact resistance of around 1.7x10-4 Ω-cm2. This substantial improvement is attributed to the high carrier concentration of the 1T’-MoTe2 intermediate layer, facilitating increased tunneling events across the van der Waals gap and enhancing carrier transport between the metal and 2H-MoTe2.
期刊介绍:
Nanoscale Horizons stands out as a premier journal for publishing exceptionally high-quality and innovative nanoscience and nanotechnology. The emphasis lies on original research that introduces a new concept or a novel perspective (a conceptual advance), prioritizing this over reporting technological improvements. Nevertheless, outstanding articles showcasing truly groundbreaking developments, including record-breaking performance, may also find a place in the journal. Published work must be of substantial general interest to our broad and diverse readership across the nanoscience and nanotechnology community.