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Since the demonstration of the unique properties of single-layer graphene and transition metal dichalcogenides (TMDs), research on two-dimensional (2D) materials has become one of the hottest topics, with the family of 2D materials quickly expanding. This expansion is mainly attributable to the development of new synthesis methods to create new materials. This review will summarize and critically analyze topochemical synthesis methods for synthesizing novel 2D materials. For example, the emerging family of 2D transition metal carbides, nitrides and carbonitrides (MXenes) are synthesized primarily by selective etching of “A” (metal) elements from MAX phases. Another 2D material, hydrogenated germanene is produced by selective etching of calcium digermanide (CaGe 2 ). The topochemical transformation of one dichalcogenide into another and 2D oxides into 2D carbides or nitrides have attracted great attention because materials with many useful and diverse properties can be obtained by these methods. Topochemical synthesis methods provide alternative ways of synthesizing 2D materials not requiring van der Waals bonded solid precursors or vapor phase deposition, but they have not been comprehensively reviewed. In this review, we describe common principles of topochemical synthesis of 2D materials, explain synthesis mechanisms and offer an outlook for future research.
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Micro‐Scale Device—An Alternative Route for Studying the Intrinsic Properties of Solid‐State Materials: The Case of Semiconducting TaGeIr
An efficient application of a material is only possible if we know its physical and chemical properties, which is frequently obstructed by the presence of micro‐ or macroscopic inclusions of secondary phases. While sometimes a sophisticated synthesis route can address this issue, often obtaining pure material is not possible. One example is TaGeIr, which has highly sample‐dependent properties resulting from the presence of several impurity phases, which influence electronic transport in the material. The effect of these minority phases was avoided by manufacturing, with the help of focused‐ion‐beam, a μm‐scale device containing only one phase—TaGeIr. This work provides evidence for intrinsic semiconducting behavior of TaGeIr and serves as an example of selective single‐domain device manufacturing. This approach gives a unique access to the properties of compounds that cannot be synthesized in single‐phase form, sparing costly and time‐consuming synthesis efforts.
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- PAR ID:
- 10149193
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/anie.202002693
