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Abstract The transition metal selenides M1+ySe2(M = V, Ti) have intriguing quantum properties, which make them target materials for controlling properties by thinning them to the ultrathin limit. An appropriate approach for the synthesis of such ultrathin films is by molecular beam epitaxy. Here, it is shown that such synthesized V‐ and Ti‐Se2films can undergo a compositional change by vacuum annealing. Combined scanning tunneling and photoemission spectroscopy is used to determine compositional and structural changes of ultrathin films as a function of annealing temperature. Loss of selenium from the film is accompanied by a morphology change of monolayer height islands to predominantly bilayer height. In addition, crystal periodicity and atomic structure changes are observed. These changes are consistent with a transition from a layered transition metal dichalcogenide (TMDC) to ordered intercalation compounds with V or Ti intercalated in between two layers of their respective TMDCs. These observations may clear up misconception of the nature of previously reported high‐temperature grown transition metal selenides. More significantly, the demonstrated control of the formation of intercalation compounds is a key step toward modifying properties in van der Waals systems and toward expanding material systems for van der Waals heterostructures.
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Cephalopods as a Natural Sensor-Display Feedback System Inspiring Adaptive Technologies
Nature is full of exemplary species that have evolved personalized sensors and actuating systems that interface with and adapt to the world around them. Among them, cephalopods are unique. They employ fast-sensing systems that trigger structural changes to impart color changes through biochemical and optoelectronic controls. These changes occur using specialized optical organs that receive and respond to signals (light, temperature, fragrances, sound, and textures) in their environments. We describe features that enable these functions, highlight engineered systems that mimic them, and discuss strategies to consider for future cephalopod-inspired sensor technologies.
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- Award ID(s):
- 1945207
- PAR ID:
- 10423795
- Publisher / Repository:
- The Electrochemical Society
- Date Published:
- Journal Name:
- ECS Sensors Plus
- Volume:
- 2
- Issue:
- 2
- ISSN:
- 2754-2726
- Page Range / eLocation ID:
- Article No. 023601
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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