Two-Dimensional Growth of Free-Standing Nanosheets and Heterostructures by Ionic Layer Epitaxy
Technical Report,01 May 2016,30 Apr 2019
University of Wisconsin - Madison Madison United States
Pagination or Media Count:
Major Goals Task 1 Understand the kinetics that controls the thickness and monocrystalline size. Two governing factors GFs that control the nanosheet thickness will be studied 1 the strength of the electric field built by the ionic surfactant monolayer and 2 the ionic strength in the bulk phase. A relationship between the two GFs and the thicknesses of the amorphous and monocrystalline nanosheets will be established and advanced to a generic model that describes ILE and predicts the growth outcomes. Ex-situ and in-situ TEM study will be conducted to reveal how the large number of nuclei align and grow into large monocrystalline sheets, which determines the monocrystalline size. Task 2 Explore the growth of nanosheets of other materials by ILE. Guided by the rich library of aqueous solution synthesis recipes of inorganic nanomaterials in literature, the ILE technique will be applied to the growth of freestanding ultrathin nanosheets from broader material systems, including oxides, chalcogenides, and metals. Existing recipes in literature will be integrated with ionic surfactant monolayer systems to alter the morphology of the products from these recipes producing ultrathin nanosheets. Task 3 Growth of nanosheet heterostructures by ILE. Following the success of ILE growth of a number of materials, we will investigate the growth of nanosheet heterostructures with either side-by-side lateral junctions or face-to-face vertical junctions. Multilayer nanosheets vertical heterostructures will be synthesized by integrating ILE with liquid phase epitaxy. Lateral nanosheet homo-heterojunctions will be synthesized by constructing two ILE systems in the same aqueous solution using a monolayer consisting of two immiscible ionic surfactants.
- Physical Chemistry