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Smyth CM, Cain JM, Boehm A, Ohlhausen JA, Lam MN, Yan X, Liu SE, Zeng TT, Sangwan VK, Hersam MC, Chou SS, Ohta T, Lu TM. Direct Characterization of Buried Interfaces in 2D/3D Heterostructures Enabled by GeO 2 Release Layer. ACS APPLIED MATERIALS & INTERFACES 2024; 16:2847-2860. [PMID: 38170963 DOI: 10.1021/acsami.3c12849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Inconsistent interface control in devices based on two-dimensional materials (2DMs) has limited technological maturation. Astounding variability of 2D/three-dimensional (2D/3D) interface properties has been reported, which has been exacerbated by the lack of direct investigations of buried interfaces commonly found in devices. Herein, we demonstrate a new process that enables the assembly and isolation of device-relevant heterostructures for buried interface characterization. This is achieved by implementing a water-soluble substrate (GeO2), which enables deposition of many materials onto the 2DM and subsequent heterostructure release by dissolving the GeO2 substrate. Here, we utilize this novel approach to compare how the chemistry, doping, and strain in monolayer MoS2 heterostructures fabricated by direct deposition vary from those fabricated by transfer techniques to show how interface properties differ with the heterostructure fabrication method. Direct deposition of thick Ni and Ti films is found to react with the monolayer MoS2. These interface reactions convert 50% of MoS2 into intermetallic species, which greatly exceeds the 10% conversion reported previously and 0% observed in transfer-fabricated heterostructures. We also measure notable differences in MoS2 carrier concentration depending on the heterostructure fabrication method. Direct deposition of thick Au, Ni, and Al2O3 films onto MoS2 increases the hole concentration by >1012 cm-2 compared to heterostructures fabricated by transferring MoS2 onto these materials. Thus, we demonstrate a universal method to fabricate 2D/3D heterostructures and expose buried interfaces for direct characterization.
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Affiliation(s)
| | - John M Cain
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Alex Boehm
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - James A Ohlhausen
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Mila Nhu Lam
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Xiaodong Yan
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Stephanie E Liu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Thomas T Zeng
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Vinod K Sangwan
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Stanley S Chou
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Taisuke Ohta
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Tzu-Ming Lu
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
- Center for Integrated Nanotechnologies (CINT), Sandia National Laboratories, Albuquerque, New Mexico 87123, United States
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Boehm A, Fonseca JJ, Thürmer K, Sugar JD, Spataru CD, Robinson JT, Ohta T. Engineering of Nanoscale Heterogeneous Transition Metal Dichalcogenide-Au Interfaces. NANO LETTERS 2023; 23:2792-2799. [PMID: 37010816 DOI: 10.1021/acs.nanolett.3c00080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Engineering the transition metal dichalcogenide (TMD)-metal interface is critical for the development of two-dimensional semiconductor devices. By directly probing the electronic structures of WS2-Au and WSe2-Au interfaces with high spatial resolution, we delineate nanoscale heterogeneities in the composite systems that give rise to local Schottky barrier height modulations. Photoelectron spectroscopy reveals large variations (>100 meV) in TMD work function and binding energies for the occupied electronic states. Characterization of the composite systems with electron backscatter diffraction and scanning tunneling microscopy leads us to attribute these heterogeneities to differing crystallite orientations in the Au contact, suggesting an inherent role of the metal microstructure in contact formation. We then leverage our understanding to develop straightforward Au processing techniques to form TMD-Au interfaces with reduced heterogeneity. Our findings illustrate the sensitivity of TMDs' electronic properties to metal contact microstructure and the viability of tuning the interface through contact engineering.
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Affiliation(s)
- Alex Boehm
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Jose J Fonseca
- Jacobs Technology Contractor at the U.S. Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Konrad Thürmer
- Sandia National Laboratories, Livermore, California 94550, United States
| | - Joshua D Sugar
- Sandia National Laboratories, Livermore, California 94550, United States
| | - Catalin D Spataru
- Sandia National Laboratories, Livermore, California 94550, United States
| | | | - Taisuke Ohta
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
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Xiao Y, Xiong C, Chen MM, Wang S, Fu L, Zhang X. Structure modulation of two-dimensional transition metal chalcogenides: recent advances in methodology, mechanism and applications. Chem Soc Rev 2023; 52:1215-1272. [PMID: 36601686 DOI: 10.1039/d1cs01016f] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Together with the development of two-dimensional (2D) materials, transition metal dichalcogenides (TMDs) have become one of the most popular series of model materials for fundamental sciences and practical applications. Due to the ever-growing requirements of customization and multi-function, dozens of modulated structures have been introduced in TMDs. In this review, we present a systematic and comprehensive overview of the structure modulation of TMDs, including point, linear and out-of-plane structures, following and updating the conventional classification for silicon and related bulk semiconductors. In particular, we focus on the structural characteristics of modulated TMD structures and analyse the corresponding root causes. We also summarize the recent progress in modulating methods, mechanisms, properties and applications based on modulated TMD structures. Finally, we demonstrate challenges and prospects in the structure modulation of TMDs and forecast potential directions about what and how breakthroughs can be achieved.
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Affiliation(s)
- Yao Xiao
- Collaborative Innovation Centre for Advanced Organic Chemical Materials Co-Constructed by the Province and Ministry, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, P. R. China.
| | - Chengyi Xiong
- Collaborative Innovation Centre for Advanced Organic Chemical Materials Co-Constructed by the Province and Ministry, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, P. R. China.
| | - Miao-Miao Chen
- Collaborative Innovation Centre for Advanced Organic Chemical Materials Co-Constructed by the Province and Ministry, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, P. R. China.
| | - Shengfu Wang
- Collaborative Innovation Centre for Advanced Organic Chemical Materials Co-Constructed by the Province and Ministry, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, P. R. China.
| | - Lei Fu
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan 430072, P. R. China. .,College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China.
| | - Xiuhua Zhang
- Collaborative Innovation Centre for Advanced Organic Chemical Materials Co-Constructed by the Province and Ministry, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, P. R. China.
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Schram T, Sutar S, Radu I, Asselberghs I. Challenges of Wafer-Scale Integration of 2D Semiconductors for High-Performance Transistor Circuits. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109796. [PMID: 36071023 DOI: 10.1002/adma.202109796] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Large-area 2D-material-based devices may find applications as sensor or photonics devices or can be incorporated in the back end of line (BEOL) to provide additional functionality. The introduction of highly scaled 2D-based circuits for high-performance logic applications in production is projected to be implemented after the Si-sheet-based CFET devices. Here, a view on the requirements needed for full wafer integration of aggressively scaled 2D-based logic circuits, the status of developments, and the definition of the gaps to be bridged is provided. Today, typical test vehicles for 2D devices are single-sheet devices fully integrated in a lab environment, but transfer to a more scaled device in a fab environment has been demonstrated. This work reviews the status of the module development, including considerations for setting up fab-compatible process routes for single-sheet devices. While further development on key modules is still required, substantial progress is made for MX2 channel growth, high-k dielectric deposition, and contact engineering. Finally, the process requirements for building ultra-scaled stacked nanosheets are also reflected on.
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Affiliation(s)
- Tom Schram
- Imec, kapeldreef 75, Heverlee, B7001, Belgium
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