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Abstract The structural integrity of atomically thin two-dimensional molybdenum disulfide (MoS2) is crucial for high-temperature applications, including nanoelectronics and optoelectronics. This study explores the structural stability and electrical performance, under extended thermal exposure in air, of MoS2flakes synthesized via chemical vapor deposition (CVD) and mechanical exfoliation. The MoS2flakes, both CVD-grown and mechanically exfoliated, were subjected to heating at 200 °C with a relative humidity of 60(±5)% for a prolonged period and investigated with atomic force microscopy and Raman spectroscopy. This study shows that CVD-grown flakes developed noticeable cracks after prolonged heating, whereas mechanically exfoliated flakes mostly retained their structural integrity. Also, both types of flakes showed a decrease in layer thickness and lateral size over time, with mechanically exfoliated flakes exhibiting a comparatively smaller reduction in substrate coverage area. In addition, MoS2-based two-terminal devices were subjected to heating at 150 °C for approximately 1100 h, and their electrical characterization revealed a steady rise in current during constant voltage (5 V) conditions. This study enhances our understanding of MoS2stability and provides guidance for improving the reliability of MoS2-based devices in high-temperature electronic applications.
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Physical adsorption and oxidation of ultra-thin MoS 2 crystals: insights into surface engineering for 2D electronics and beyond
Abstract The oxidation mechanism of atomically thin molybdenum disulfide (MoS2) plays a critical role in its nanoelectronics, optoelectronics, and catalytic applications, where devices often operate in an elevated thermal environment. In this study, we systematically investigate the oxidation of mono- and few-layer MoS2flakes in the air at temperatures ranging from 23 °C to 525 °C and relative humidities of 10%–60% by using atomic force microscopy (AFM), Raman spectroscopy and x-ray photoelectron spectroscopy. Our study reveals the formation of a uniform nanometer-thick physical adsorption layer on the surface of MoS2, which is attributed to the adsorption of ambient moisture. This physical adsorption layer acts as a thermal shield of the underlying MoS2lattice to enhance its thermal stability and can be effectively removed by an AFM tip scanning in contact mode or annealing at 400 °C. Our study shows that high-temperature thermal annealing and AFM tip-based cleaning result in chemical adsorption on sulfur vacancies in MoS2, leading to p-type doping. Our study highlights the importance of humidity control in ensuring reliable and optimal performance for MoS2-based electronic and electrochemical devices and provides crucial insights into the surface engineering of MoS2, which are relevant to the study of other two-dimensional transition metal dichalcogenide materials and their applications.
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- Award ID(s):
- 2006127
- PAR ID:
- 10487419
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Nanotechnology
- Volume:
- 34
- Issue:
- 40
- ISSN:
- 0957-4484
- Format(s):
- Medium: X Size: Article No. 405701
- Size(s):
- Article No. 405701
- Sponsoring Org:
- National Science Foundation
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